CHEMICAL CONTROL 
OF TEA PESTS 
< 
* 
a 
V S Sidhakaran 
Tea Research Institute of Sri Lanka 
CHEMICAL CONTROL OF 
TEA PESTS 
VSSidhakaran 
B.Sc. (Agri.), M.Sc. (Agri.) 
Published by 
Tea Research Institute of Sri Lanka 
2006 
© The Tea Research Institute of Sri Lanka, 
All rights reserved. No part of this publication may be produced, stored in 
a retrieval system, or transmitted in any form or by any means, electronic, 
mechanical, photocopying, recording or otherwise, without the prior 
permission of the Director, The Tea Research Institute of Sri Lanka, 
Talawakelle, Sri Lanka. 
First Published 1997 
Second Edition 2006 
Tea Research Institute of Sri Lanka 
Talawakelle 
Sri Lanka 
www.tri.lk 
E-mail: postmast@tri.ac.lk 
Preface 
This book on "Chemical Control of Tea Pests" is the second edition 
and was first published in 1997. The book was brought out with a 
view to provide ready made information on all the pesticides 
currently recommended by the TRI mainly for various levels of 
practitioners such as Plantation Managers, Supervisors and Small 
Holders. The book will serve as an efficient reference to find out 
precise information about the pesticides and its usage in tea 
particularly for busy practitioners, who do not find time to go 
through a bulk of literature. During the revision I have attempted 
to improve the user friendliness of this edition based on the valuable 
comments received from the users of the previous edition. 
The names of the pesticides mentioned in the book are common 
names. Their trade names are given within brackets. 
In addition to revised recommendations of pesticides, this book 
includes some useful information regarding pest management and 
pesticide use. It is expected that such information will help the 
grower to use pesticides judiciously in view of food safety aspects 
and environment aspects which are important issues in the present 
day context. The additional information included in this edition 
covers the areas such as basics of tea pest management, various 
strategies of tea pest management, judicious use of pesticides in 
tea, proper timing of chemical control (particularly in case of tea 
tortrix), guide to identify common pests in tea and damage 
symptoms of insect and mite pests, nematodes, diseases and 
weeds. 
VSSidhakaran 
Advisory Officer 
Tea Research Institute of Sri Lanka 
vsidha @yahoo .com August 2006 
Acknowledgement 
The author sincerely thanks Dr. M T Ziyad Mohamed, Director, 
TRI for his prompt initiative to revise this book and all necessary 
support in completing the revision. 
The author wishes to place on record the invaluable contributions 
by several TRI Scientists by giving valuable comments on their 
respective subject areas namely; Dr. A Balasooriya/Head, Plant 
Pathology Division, Dr. A M T Amarakoon/ Senior Research Officer, 
Biochemistry Division, Dr. K G Prematilake/ Senior Research Officer, 
Agronomy Division, Dr. K Mohotti /Senior Research Officer, 
Entomology Division, Mr. B A D Samansiri/Head, Advisory and 
Extension Division, Mr. S Walgama/Actg. Officer in Charge, 
Entomology Division, and Mrs. M S D Luxmei de Silva/Senior 
Research Officer, Agronomy Division. 
The editorial support rendered by Dr. A. K. N. Zoysa, 
Chairperson / Publications and Presentations Panel of the TRI is 
highly valued. 
Many of the photographs of diseases and weeds were provided 
by Dr. Balasooriya and Mrs. Luxmei de Silva respectively to whom 
the author is grateful. Assistance rendered by the Photography 
Unit of the TRI for taking quality photographs is greatly 
acknowledged. 
i-
Finally the author is thankful to Ms Kumari Kiribathgoda for her 
unstinted assistance in typing the text and, to the colleagues of 
the Advisory Division, Talawakelle, for their cooperation. 
Basics of tea pest management 01 
A brief look at the management strategies of tea pests 
recommended by the TRI 07 
Judicious use of pesticides in tea 11 
Recommended pesticides for tea cultivation 15 
Classification of pesticides 17 
Insecticides 24 
Guide to identify major insect pests of tea • 33 
Acaricides/miticides 36 
Guide to identify major mite pests of tea 38 
Nematicides 40 
Guide to identyfy nematode pests of tea 41 
Soil fumigants 42 
Fungicides 47 
Guide to identify common diseases of tea 58 
Herbicides 64 
Miscellaneous 75 
Guide to identify common weeds in tea lands 77 
Herbicide toxicity symptoms in tea plants 83 
Guidelines for the safe use of pesticides 84 
Standard spray equipment 92 
Some useful hints for effective spraying 97 
Useful conversions 100 
Bibiliography 101 
BASICS OF TEA PEST MANAGEMENT 
Crop loss due to pests 
In general agricultural terms, pest can be defined as, a living organism, 
such as an insect, a fungus or a weed, that has a damaging effect on crop 
plants, livestock or stored products. 
In tea cultivation, like in any other crop cultivation, there are number of 
pests that interfere with crop productivity. Tea being a long-term perennial 
crop, a sustainable pest management approach is of paramount importance 
in tea cultivation. The concept of pest management depends on the 
population dynamics of pests and the level of damage caused by them. On 
an agricultural basis, one is concerned whether crop damage caused by 
insects, diseases, etc, lead to a loss in yield or quality, resulting in an income 
loss. When the yield loss reaches a certain proportion, the pest can be 
defined as an economic pest. The value of the crop is of paramount 
importance in this case and it is difficult to generalize, but as a general 
guide for most crops, the pest species reach economic pest status, when 
there is a 5 - 10% loss in yield (Arunachalam, 1995). 
It is necessary to highlight the magnitude of crop losses in plantations due 
to pests to understand the importance of pest control programes. 
Severe infestation by termites and shot hole borer leads not only to crop 
loss but also capital loss resulting from the death of bushes in the long run. 
There have been several assessments of crop loss caused by different tea 
pests. 
1 
CHEMICAL CONTROL OF TEA PESTS 
A crop loss of 8% has been attributed to insect pests on tea in Asia (Cramer, 
1967). Das (1965) estimated it to be in the range of 7-10% on an average, 
with severe outbreaks of certain pests causing 15 - 25% loss of crop. 
This can be even higher in the case of cultivars that are very susceptible 
to the primary pests of tea (Vitarana, 1990, unpublished data). 
Scarlet and red spider mites are reported to cause 0.5 - 5.0 % decrease in 
yield (Danthanarayna and Ranaweera, 1970). 
It has been attributed that 4 to 40% crop loss due to plant parasitic 
nematodes of tea in Sri Lanka (Gnanapragasam,1988). The yield loss had 
been earliar estimated to be in the range of 225 - 350 kg made tea per ha 
per year (Sivapalan, 1972; Visser, 1959). 
Crop loss due to blister blight disease (in western Up country sector), was 
estimated over an entire cycle, the average was found to be in the range 
of 20% - 25%, with no protection measures adopted (Visser et al., 1958). 
Crop loss is greater during the first half of the cycle. 
It has been estimated that crop loss due to weeds in tea land to be 7.5 to 
10 per cent and it is more during the second year of pruning cycle compaired 
to the third year in a three-year cycle (Eden, 1941). Wettasinghe (1970) 
report 5 - 1 5 percent yield loss in VP tea under Low country conditions 
when weeding was delayed for 4 - 6 months. Visser (1961) reported as 
much as 30 percent yield reduction in young tea when there was heavy 
weed infestation. 
In general estimated crop losses due to pests, diseases and weeds are 
given as 8%, 16% and 16% respectively hence, the total crop loss as 40% 
(Hudson et al., 2002). Some times there is capital loss due to death of 
bushes. 
2 
BASICS OF TEA PEST MANAGHMI NT 
Levels of pest damage and the concept of economic threshold level 
and economic injury level 
There are three levels of pest damage, namely Equilibrium position, 
Economic threshold level and Economic injur} level. Equilibrium position 
is where average density of the pest population exist over a long period of 
time without aggravation, and does not warrant spending money to control 
it. 
Economic threshold level is where it is desirable that control measures 
are adopted in order to prevent a pest population from causing actual economic 
injur}'. Economic threshold is the population density of an increasing pest 
population at which level control measures should be started to prevent the 
population reaching the economic injury level. 
Economic injury level is the lowest population density that will cause 
economic damage and will vary among crops, season and areas. Any 
control measure taken at this level will have a cost benefit ratio of 1:1. 
Therefore it is left with the discretion of the manager grower to act, taking 
various factors like weather and marketing aspects into consideration 
particularly in the case of seasonal pests. 
= 
Change in pest population density 
over time 
a 
s 
-
Economic Injury Level 
Economic Threshold 
Time 
3 
CHEMICAL CONTROL OF TEA PESTS 
The concept of economic threshold level and economic injury level is 
indicated by the graph in the previous page. This is a useful concept 
because it quantifies the cost/benefit ratio that underlies pest control 
decisions. In practice, however, it is not always necessary or desirable to 
wait until a population reaches the economic injury level before initiating 
control measures. Once it is determined that a population will reach 
outbreak status, prompt action can maximize the return on a control 
investment. Since there is usually a lag time between the implementation 
of a control strategy and its effect on pest population, it is always desirable 
to begin control measures before the pest actually reaches the economic 
injury level. Consequently, a point below the economic injury level at which 
a decision is made to treat or not to treat. This decision point is called the 
economic threshold, or some times action threshold. It is the decision 
point for action, the pest density at which steps are first taken to ensure 
that a potential pest population never exceeds its economic injury level. 
The economic threshold, like the economic injury level, is usually expressed 
in units of insect density or in terms of an injury measurement. The 
economic threshold is always lower than the economic injury level in 
order to allow for sufficient time to enact control measures. 
Assessment of damage component 
Degree of damage is the monetary value of the crop loss on account of 
the pest. This should be assessed as a prerequisite for decision making. 
Crop loss is directly proportional to the level of infestation of the pest. 
Therefore by assessing the level of pest infestation we can deduce the 
monetary loss that would result. 
Method of assessing pest infestation level is based on the habits of the 
pest e.g. in the case of shot-hole borer we examine parts of stem of a 
particular growth to assess shot-hole borer infestation level, whereas, it is 
the leaf that we examine in the case of tea tortrix infestation. 
4 
BASICS OF TEA PEST MANAGEMENT 
Various methods of pest control 
Cultural : Manipulation of cultural practices to avoid the high impact 
of pests and use of pest-resistant cultivars. Adjusting 
plucking rounds, proper timing of pruning, shade 
management and cover crops are some of the examples. 
Mechanical : This method, the oldest pest control method, involve 
manual collection and destruction of the pest. Some 
insects attracted by light, are trapped in the night by 
keeping lanterns in the field. There are various trapping 
devices designed by Entomologists. Removal of weeds 
manually or mechanically (by means of hand, knife, sickle 
or wire code mounted to a brush cutter). 
Biological : This includes the use of living organisms to control the 
pest. For instance, predators, parasites and pathogens by 
augmentation and introduction. The main advantage of 
biological method is that it obviates the necessity of using 
chemical poisons. Most successful cases have produced 
long-term control from one introduction e.g. parasites and 
pathogens, on tea tortrix and mite control. 
Chemical : This refers to the use of chemicals in controlling pests. 
There are chemicals with different modes of action such 
as contact, stomach and systemic insecticides, insect 
growth regulators, chemosterilants and pheromones for 
trapping and herbicides for weed control. 
Legal : Quarantine measures by which introduction of foreign 
pests are being prevented. 
I.P.M. : Integrated Pest Management: combining of different 
methods of control for best results at a lowest cost and a 
more environmentally friendly way. In case of weed 
management the term IWM (Integrated Weed 
Management) is used. 
5 
CHEMICAL CONTROL OF TEA PESTS 
Integrated Pest Management (IPM) 
In good pest control systems, pests are managed and not eliminated. 
Integrated control is directed at providing treatments that are both economic 
and of least detriment to the environment. 
Integrated control may be defined as an ecological approach to pest control 
based on studies of the life systems of the pests and the ecosystems of 
which they are part. The goal of IPM is to mitigate pest damage while 
protecting human health, the environment and economic viability. 
When pest management decisions are made, diversity of public and private 
values should be taken into consideration. 
Disturbances, to the ecosystem tend to be more violent when a single 
method is applied at maximum force (like being over dependent on 
pesticides). Therefore, integrated control usually involves a combination 
of many treatments, preferably including self-propagative methods, leading 
to greater stability of the system in the long term and preserving the 
environment. 
The objective is not complete displacement of pesticides, but their 
incorporation where necessary into a balanced programme to free the 
undesirable side effects. 
Pesticides continue to play a major part in integrated pest management, 
but their nature will change tending to become more specific and more 
closely related to the existing biological agents such as pheromones, growth 
regulators, parasites, pathogens etc. One reason why integrated control 
usually involves a combination of treatments is that the principle of 
diminishing returns means that, with complete dependence on one type of 
treatment, the cost of further improvements, after a certain level of 
efficiency is reached is disproportionately high compared with the 
introduction of another type of treatment to obtain an equivalent increase. 
6 
A BRIEF LOOK AT THE MANAGEMENT STRATEGIES OF TEA 
PESTS RECOMMENDED BY THE T R I 
Pest/Disease/Weed Occurrence Management strategies 
Pests 
Pests feeding on the leaf 
1 Tea Tortrix 
(Homona coffearia) 
Seasonal Pest • Natural bio-control agents 
(parasites, predators & 
pathogens) 
• Chemical control, if natural 
control fails 
2. Yellow Mite 
(Hemitarsonemus latus) 
Occasional & 
Seasonal Pest 
• Chemical spray in nurseries & 
fields recovering from prune 
• Hard plucking in mature tea 
3 Fringed Nettle Grub 
(Macroplectra nararia 
Syn (Darna nararia) 
Seasonal Pest • Chemical spray early at 
outbreaks/ spot spraying 
4 Red Spider Mite 
(Oligonychus coffeae) 
Seasonal Pest • By natural predators 
• Chemical spray at first signs 
of outbreaks 
5. Scarlet Mite 
(Brevipalpus californicus) 
Seasonal Pest • By natural predators 
• Chemical spray in spot 
applications in outbreaks 
6. Purple Mite 
(Calacarus carinatus) 
Seasonal Pest • By natural predators 
• Chemical spray 
7 Pink Mite 
(Acaphylla theae) Seasonal Pest • Chemical spray 
7 
CHEMICAL CONTROL OF TEA PESTS 
Pest/Disease/Weed Occurrence Management strategies 
Pests feeding on the stem 
8 Shot-hole borer 
(Xyleborus fornicatus) 
Key/Primary Pest • Planting resistant cultivars 
• Maintain a healthy bush frame 
• Bush sanitation at prune 
• Chemical spray 
9. Scavenging Termites 
(there are several species) 
Secondary Pest • Ensure bush health & vigour. 
• Adopt good sanitation practices 
at pruning to keep termites 
away 
• Chemical spray only to contain 
the problem until next 
sanitation prune 
1Q Low-country live wood 
termites 
(Glyptotermis dilatatus) 
(Neotermes greeni). 
Key/Primary Pest • Plant resistant cultivars 
• Adopt bush sanitation at every 
prune 
• Infill with resistant cultivars 
• Replant if damage is heavy 
• Encourage bird & other 
predators by having shade trees 
Pests feeding on roots 
11. The Up-country live wood 
termite 
f Postelectrotermes militaris) 
Key/Primary Pest • Up-root & destroy (burning) 
infested bushes/parts in situ 
• Avoid taking infested parts 
to other places 
• Extend the period of soil 
rehabilitation with grass 
12 While grubs Cockchafers 
(Holotrichia disparilis & 
Microtrichia costata) 
Occasional Pest • Apply chemicals during field 
planting 
• Inhighlywhitegrubpione areas, 
avoid application of organic material 
to the planting hole 
8 
A BRIEF LOOK AT THE MANAGEMENT STRATEGIES OF 
TEA PESTS RECOMMENDED BY THETRI 
Pest/Disease/Weed Occurrence Management strategies 
13. Nematodes: 
Root lesion nematode 
(Pratylenchus loosi) 
Burrowing nematode 
(Radopholus similes) 
Key/Primary Pest • Prevent Infestation during 
nursery stage & in the field 
• Use resistant/tolerant cultivars 
• Rehabilitate soil with grass 
before tea planting 
• Prophylactic chemical treatment 
at field planting 
• Enrich soil with organic matter 
Diseases: 
Leaf diseases 
L Blister Blight 
(Exobasidium vexans) 
Seasonal Disease • Avoid susceptible cultivars 
• Cultural Measures 
• Chemical Spray 
2 Black Blight Disease 
(Rizoctonia solani) 
Seasonal/Occasional 
Disease 
• Cultural Measures 
• Chemical Spray 
Stem diseases 
3 Red Rust Disease 
(Cephaleuros parasiticus) 
Occasional Disease • Cultural Measures 
• Chemical spray 
4 Stem & Branch Canker 
(Macrophoma thekola) 
Secondary Disease • Avoid susceptible cultivars 
• Cultural Measures 
• Chemical Spray 
5 Collar & Branch Canker 
(Phomopsis theae) 
Secondary Disease • Avoid susceptible cultivars' 
• Cultural Measures 
6 Hypoxylon Stem Blight 
(Nemania diffusa) 
Secondary Disease 
Elevation Specific 
• Avoid susceptible cultivars 
• Cultural measures 
7 Thorny Stem Blight 
(Tunstallia aculeate) 
Secondary Disease • Avoid susceptible cultivars 
• Cultural Measures 
9 
CHEMICAL CONTROL OF TEA PESTS 
Pest/Disease/Weed Occurrence Management strategies 
8 General wood rot Secondary Disease • Cultural Measures 
9 Horse-hair Blight 
(also on leaves) 
(Marasmius equicrinis) 
Potential Problem in 
the Low Country 
• Cultural Measures 
• Manual Methods 
• Lime Spray 
• Chemical Spray 
Root diseases 
1Q Red Root Disease 
(Poria hypolateritia) 
Primary Disease • Integrated Management 
• Cultural Measures 
• Chemical use 
11. Black Root Disease 
(Rosellinia arcuata) 
Primary Disease • Cultural Measures 
• Chemical use 
12. Charcoal Root Disease 
(Ustulina deusta) 
Primary Disease • Cultural Measures 
• Chemical use 
13. Brown Root Disease 
(Phellinus noxious) 
Primary Disease • Cultural Measures 
• Chemical use 
14. White Root Disease 
(Rigidoporus microporus) 
Primary Disease • Cultural Measures 
• Chemical use 
15. Weeds • Preventive Measures 
• Cultural Measures 
• Manual Methods 
• Chemical Methods 
• Biological Methods 
10 
JUDICIOUS USE OF PESTICIDES IN TEA 
As discussed above, the best approach of pest management is to combine 
various pest control methods (IPM) including chemicals when they are 
indispensable. Chemical control method remains a powerful tool which is 
quick in action against majority of pest outbreaks. Results through chemical 
control are more predictable. However, the growers should be well aware 
of the limitations of chemical control methods. One should not over depend 
on chemicals. The disadvantages or limitations of pesticide chemicals are 
well known. In a brief review, the disadvantages of over dependence on 
pesticide usage can be listed as follows: 
• Development of strains of pests which are resistant to pesticides. 
• Temporary effects on pest populations necessitating repeated 
treatment/application. 
• Hazards from residues of the pesticide in the harvested crop. 
• Outbreaks of unleashed secondary pests resulting from the 
destruction of their natural enemies. 
Undesirable side-effects on non-target organisms including 
parasites and predators; 
Fish, birds and other wild life; 
Honey bees and other necessary pollinators; 
Man and his domestic animals; and 
The crop 
• Direct hazards in the application of pesticides. 
• Reduction and simplification of the biotic component of the agro-
ecosystem. 
11 
CHEMICAL CONTROL OF TEA PESTS 
Successes depend on the judicious use of pesticides with the view that 
we do not need full elimination of the pest. We have encountered severe 
problems with pesticides when we have tried to achieve full control with 
pesticides alone. 
"Maximum Residue Limits" (MRL s) of pesticides in made tea 
Over dependence on chemical pest control methods/excessive use of 
pesticides can leave exessive residues of pesticides in the harvested crop 
i.e. tea. Demands of health conscious tea consumers all over the world 
desire teas free of or minimally contaminated with chemicals. As our teas 
are mainly exported, judicious use of pesticides is an important issue in 
the present day context. The pesticides recommended by the TRI are 
often reviewed in view of the current international food and safety issues 
particularly on pesticide residues. 
The new European Union regulation (852/2005) on the hygiene of food 
stuff (including tea), has become effective from January 2006. In Japan, 
the Ministry of Health, Labour and Welfare (MHLW) has also enforced 
its food sanitation laws with effect from May 2006. This has listed 430 
chemical pesticides to be tested in any food stuff imported to Japan 
including tea. The table below shows the pesticides recommended by the 
TRI and their MRL's (agreed upon by EU and Japan, as at 2006). 
12 
JUDICIOUS USE OF PESTICIDES IN TEA 
Chemicals recommended for use in tea plantations by TRI and 
its MRLs set out by Japan and EU (as at June, 2006) 
Na Chemical name Type Japanese MRL 
(PPm) 
for made tea 
EUMRL 
(ppm)for 
made tea 
1. 2,4-D H 0.01 0.1 
2. Azadirachtin A , I&N Exempted -
3. Bitertanol F 0.1 0.1 
4. Carbofuran I & N 0.2 0.2 
5. Carbosulfan I 0.1 0.1 
6. Chlorfluazuron I 10.0 -
7. Copper hydroxide F •• Exempted -
8. Copper Oxide F Exempted -
9. Copper Oxychloride F Exempted -
10. Dazomet N 0.1 -
11. Diazinon I 0.1 0.05 
12. Diuron H 1.0 -
13. Fenthion I 0.01 0.1 
14. Glufosinate-Ammonium H 0.5 -
15. Glyphosate H 1.0 2.0 
16. Hexaconazole F 0.05 0.05 
17. Imidachloprid I 10.0 -
18. MCPA H 0.01 -
19. Metam Sodium I & N 0.1 -
20. Oxyfluorfen H 0.01 -
21. Paraquat H 03 0.05 
22. Phenamiphos N 0.05 0.1 
23. Propargite A 5.0 5.0 
24. Propiconazole F 0.1 0.1 
25. Sulfur A Exempted -
26. Tebuconazole F 30 -
27. Tebufenozide I 25 -
A-Acaricide; I-Insecticide; N-Nematicide; F-Fungicide; H-Herbicide 
MRL - Maximum Residue Limit 
ppm- Parts per million (mg/kg of made tea) 
13 
CHEMICAL CONTROL OF TEA PESTS 
Measures to keep the residue levels low in tea 
1. Use only those pesticides that are recommended by the TRI 
following specific guidelines i.e. dosage rates, application intervals, 
pre-harvest intervals, etc. 
2. Use the chemicals in rotation - application should be need-based. 
3. Spray pesticides to the foliage only after plucking. 
4. Do not use pesticides which have crossed shelf life (expired). 
5. Use only conventional sprayers. 
6. Do not harvest until 'Pre Harvest interval' specified for the 
chemical is completed. 
Sri Lankan tea "Cleanest tea in the world" with respect to pesticide 
residues 
The adoption of TRI-recommended Integrated Pest Management (IPM) 
approach by the growers, helped to maintain a very low level of pesticide 
residues in Sri Lankan tea. Independent surveys of origin teas such as EU 
surveillance have shown that Sri Lankan tea have a very low incidence of 
pesticide residues. 
14 
RECOMMENDED PESTICIDES FOR TEA CULTIVATION 
(as at August 2006) 
Target Recommended pesticide/s 
(common name) 
Refer page 
No. 
Shot-hole borer Fenthion 30 
Tea Tortrix 
Nettle Grub 
Looper caterpillar 
Twig caterpillar 
Red Slug 
Chlorfluazuron 
Tebufenozide 
24 
24 
Red Spider Mite 
Yellow Mite 
Scarlet Mite 
Purple Mite 
Propargite 
Sulphur 
36 
37 
White Grub 
Scavenging Termites 
Cut worms 
Carbosulfan 32 
Ants Diazinon 31 
Leaf miner 
Thrips 
Scale insects 
Aphids 
Mealy Bug 
Lygus Bug 
Fenthion 30 
Nematodes Phenamiphos 
Carbofuran 
Dazomet 
40 
40 
42 
15 
CHEMICAL CONTROL OF TEA PESTS 
Blister blight Copper oxide 
Copper oxychloride" 
Copper hydroxide 
Bitertanol 
Propiconazole 
Hexaconazole 
Tebuconazole 
47 
4 8 
Black blight Copper Oxide 
Copper Oxychloride 
Copper Hydroxide 
56 
Red root disease Bitertanol 
Propiconazole 
Tebuconazole 
54 
Stem & branch 
canker 
Bitertanol 55 
Horse-hair blight Hydrated lime 
Copper fungicides 
Systemic fungicides 
57 
Wood rot in prune 
cuts 
Bitertanol paint 
Copper Oxychloride/ Sulphur 
with Linseed oil 
Kandasan 
57 
Broad-leaved weeds 
. & grass weeds 
Paraquat 
Glyphosate 
Glufosinate ammonium 
67 
70 
72 
Broad-leaved weeds 2,4D 
MCPA 
68 
69 
Weed seeds Diuron 
Oxiflurorfen 
70 
71 
Moss and lichens on 
the frames 
Hydrated lime 75 
16 
CLASSIFICATION OF PESTICIDES 
A substance or mixture of substances used to control pests such as insects, 
mites, nematodes, fungi, weeds, and other pests, is called a pesticide. 
These are toxic substances. Depending on their use and effectiveness, 
the commonly used pesticides in tea cultivation are grouped as follows: 
Insecticides l l l l Act on insects 
Acaricides l l l l 
Nematicides mi 
Act on mites 
Act on nematodes 
f u n g i c i d e s I I I H ^ Act on fungi 
Herbicides mi Act on weeds 
Soil Fumigants I I I H ^ Act on soil pest 
1" 
CHEMICAL CONTROL OF TEA PESTS 
It is therefore important to identify the pest correctly before choosing an 
appropriate pesticide. For instance, spraying fenthion (an insecticide) to 
control mites is of no use. Some pesticides are effective against more 
than one kind of pest e.g. Carbofuran is effective against several insects 
and nematodes. 
G r o u p i n g of pesticides based on how they act on p lan ts o r soil 
Contact pesticides: 
When applied to the 
plant soil, the) remain 
on the applied surface 
and act on the pest. 
Contact pesticides are 
not translocated within 
the plant. 
Systemic or 
translocated pesticides: 
These are absorbed by 
plants through their foliage 
or roots and translocated 
within the plant. Systemic 
pesticides are applied to 
either the foliage or to the 
soil. 
18 
CLASSIFICATION OF PESTICIDES 
Residual pesticides: 
These are applied to either plants or soil. Under favourable conditions 
they remain active in the soil or plant over a period of time. 
G r o u p i n g of pesticides based on how they act on the ta rge t pests 
(mode of action) 
Mode of action means, the way that a pesticide enters the pest and how 
it acts on it. Insecticides and acaricides may be classified according to the 
mode of entry or the effect on the pest as explained below. 
Contact poisoning: 
The pesticide enters the body as a 
result of contact with legs or other 
external parts of the body. Contact 
may occur directly during spraying or 
through contact with the sprayed 
leaves. 
Stomach poisoning: 
The pesticide enters the body through 
the mouth during feeding and is 
absorbed through the digestive tract. 
These are effective on chewing and 
biting insects. 
Respiratory poisoning: 
These are volatile pesticides. The} 
enter the body through the respirator} 
openings (spiracles) of the pest. 
19 
CHEMICAL CONTROL OF TEA PESTS 
Systemic toxicant: 
These type of pesticides are readily 
absorbed by the plant through its 
leaves/stems/roots after application. 
They enter the body when the pest 
feeds on the plant. Especial ly 
effective against sucking, boring and 
mining pests and nematodes. 
Composition of pesticides 
Pesticides contain mainly two components named as active ingredient 
and inert material. Active ingredient is the chemical which has the pesticidal 
property. Inert material is the chemically inactive substances such as fillers, 
solvents, diluents, carriers, and surface acting agent etc. Inert matters 
mainly ease application of the pesticide and minimize application hazards. 
Pesticide formulations are manufactured in various forms. Some of the 
common pesticide formulations are described below. There is an 
internationally accepted coding system for different pesticide formulation 
types. 
20 
CLASSIFICATION OF PESTICIDES 
Formulation Coding system 
Dustable powder 
Granules 
Wettable powder 
Emulsifiable concentrate 
WP 
EC 
D 
GR 
Soluble concentrate SL 
Gas generating products/Gas 
Encapsulated granules 
Control release concentrate 
Dry flowable 
Dry prilled 
DF 
DP 
CR 
GE/GA 
EG 
Dustable powder: These are generally with a low concentration of 
the active ingredient and directly applied to the target as a dust. 
Dustable Powder is made by adding the active ingredients to a fine 
inert powder or talc. They are generally used dry. 
Granules: Granular formulations are readily usable. Active ingredient 
is released when applied. Unlike dusts and spray solutions, granules 
do not cause drift hence safer to use. 
Wettable powder: These are made by combining the active ingredient 
with a fine powder. They look like dust, and is made to mix with 
water. These formulations need continuous agitation to maintain a 
suspension. The powder should be first mixed with a small amount of 
water, forming a slurry, then is added to additional water in the spray 
tank. 
Emulsifiable concentrate: The active ingredient is mixed with an 
oil base (often petroleum derivatives) forming an emulsion which is 
diluted with water for application. An emulsion is formed when diluted 
with water. 
21 
CHEMICAL CONTROL OF TEA PESTS 
Soluble concentrate: These are highly water soluble concentrates. 
Unlike the EC formulations, they do not form an emulsion when 
sprayed with water. 
Gas generating products: These are available in the form of liquid, 
tablets or granules. Produce, poisonous gas after application. 
Encapsulated granules: Is a flowable formulation and the active 
ingredient is in the micro capsules. After application the active 
ingredient diffuses through the capsule wall covering the outer surface 
with a thin film of pesticide. As a result, effective life of the active 
ingredient is extended. 
Controlled release concentrate: The active ingredient is enclosed 
together with a release control agent inside a permeable cover. When 
applied, the active ingredient is released under control to the 
environment during a specified period. 
Dry flowable: Dry flowables is a powder that can be mixed with 
water to form a suspension in a spray tank. Flowables are available 
in liquid form as well. 
Dry prilled: The formulation is made into tiny granules and can be 
mixed with water. It is dust free, hence more safer than powder 
formulation in handling. 
The amount of active ingredient in a pesticide formulation is always given 
in the label. For instance in " Lebaycid 50% EC", 50 indicates that the 
active ingredient percentage of this formulation is 50%. 
22 
CLASSIFICATION OF PESTICIDES 
A pesticide may come under different trade names but with the same 
active ingredient. 
eg-
Common name Trade names/brand names 
Carbofuran 
Copper Oxide 
Glyphosate 
Sulphur 
Furadan 3 % G, Curaterr 3 % G, etc. 
Copper Sandoz, Perenox etc. 
Counter, Glyphosate, Destroy, Round up, etc., 
Haymite 80 WP, Kumulus S 80 WP, Sofril 81 % 
etc. 
It is therefore necessary to look for the common name and the 
percentage of the active ingredient before purchasing a pesticide 
formulation. 
23 
INSECTICIDES 
Chlorfluazuron (Atabron 5 EC) 
This is a growth inhibitor which acts specifically on lepidopteran insects 
by disrupting their growth, thereby killing them. It controls Tea Tortrix, 
Nettle grubs, Tea Looper caterpillar and other caterpillars feeding on tea. 
Dosage and spray volume: 1 L per hectare in 900 L water (14 fl oz per 
acre in 80 gal water) using knapsack sprayer. 
Dilution rate for tank mixing 1.1 ml of chlorfluazuron in 1 L water. 
1 L per hectare in 250 Lwater (14 fl oz per acre in 22 gal water) using 
mist blowers. Dilution rate for tank mixing 4 ml of chlorfluazuron in 
1 L water. 
Frequency of application: In case of tea tortrix, when overlapping 
generations occur, as in the case with major outbreak periods, spraying is 
repeated at 2-week intervals. 
Pre-harvest interval/resting period: One week 
Tebufenozide (Mimic 20 F) 
Tebufenozide is a growth inhibitor. It acts on lepidopteron insects by 
disrupting their growth. It controls leaf eaters. It controls the Tea Tortrix, 
Nettle grubs, Tea Looper caterpillar and other caterpillars feeding on tea. 
Dosage and spray volume: 750 ml per hectare in 900 Lwater ( 11 fl oz. 
per acre in 80 gal. water) for knapsack sprayers. 
24 
INSECTICIDES 
Dilution rate for tank mixing, 0.8 ml of tebufenozide in 1 Lwater. 
750 ml per hectare in 250 L water ( 11 fl oz per acre in 22 gal water) for 
mist blowers. 
Dilution rate for tank mixing, 3 ml of Tebufenozide in 1 L water. 
Frequency of application: In case of tea tortrix, when overlapping 
generations occur, as in the case with major outbreak periods, spraying is 
repeated at 2-week intervals. 
Pre-harvest interval/resting period: One week 
Implementation of chemical control measures for tea tortrix: 
It is particularly important to maintain close vigilance in known 'tOrtrix-
prone fields'. The "Pheromone traps" can be employed to monitor adult 
moth activity and predict outbreaks. 
Timing of insecticidal applications should be done precisely. 
It is best to avoid blanket spraying of the whole fields. 
If proper vigilance is maintained, and if pockets of infestation are observed 
at the early stages, it may only be necessary to carry out spot-spraying. 
Areas as small as one acre could be selected for spot treatment, i.e. an 
area of about one acre in extent could be sprayed around the centre of 
the pocket observed to be affected by the pest. 
Spraying large areas should only be considered when several infested. 
pockets are observed in the field. 
Chemical control should not be attempted when the attack has advanced to 
a stage where the plucking table is totally damaged and when, seen from a 
25 
CHEMICAL CONTROL OF TEA PESTS 
distance, the tea looks severely scorched. By this time, majority of the 
caterpillars have either stopped feeding prior to pupation or perhaps, pupated. 
The insecticides recommended are the stomach poisons which have a 
short period of efficacy. Therefore, it is essential that spraying should 
be attempted only when the majority of caterpillars are fresh green 
in colour and actively feeding early instars (less than 2 cm in length) 
With the onset of rains, disease causing organisms spread rapidly to healthy 
caterpillars and natural control by the diseases becomes adequate. 
Precise timing of insecticide application becomes necessary and the 
chemical must be sprayed when Tea Tortrix caterpillars are actively feeding 
and not when the caterpillars are about to pupate or when other stages 
like moths, eggs and pupae are abundant. A chemical that falls into the 
category of "growth inhibitors" like chitin-synthesis inhibitors must be 
applied when the stages that undergo moulting are abundant. That is, 
when the different instars of the caterpillar both actively feeding and 
pupating are abundant. 
Pheromone traps for population monitoring of tea tortrix 
The emission of pheromone by the tea tortrix female moth to lure the 
males can be made use of for monitoring the build up of moth populations 
in the field and to forecast tortrix outbreaks. Such a pheromone has been 
isolated, identified and is available in synthetic form. 
The pheromone that is impregnated into a suitable material can be set in a 
trapping system to lure male moths and the numbers so trapped can be 
counted. A trapping system must be lined with a sticky surface to trap the 
male moths that are lured into the system (please contact the TRI for 
more details). 
26 
INSECTICIDES 
Timing of chemical control 
A high population of feeding caterpillars can be expected within two to 
three weeks of high moth trapping. An appropriate insecticide may be 
sprayed between two to three weeks of high moth trapping: 
Pattern of outbreaks 
Usually, there is a distinct pattern of spread of the infestation in a given 
estate every season. The first traps can be set up in the field where Tea 
Tortrix is habitually observed to appear first. More traps can be set up in 
the other fields in sequence. Towards the middle of the tortrix season, 
many fields get the infestation simultaneously. 
The small pockets of population noticed in the very early part of the dry 
season (September-November in the South-West and February-May in 
the North-East Quarter) should be left alone for the parasites to depend 
on without any attempt to control them chemically. It is those outbreaks 
occurring during the period when teas fetch high prices (particularly in 
Up-country and Uva) that should be suppressed by means of a chemical 
sprayed at the correct time. 
A m e t h o d of a s se s s ing tea tor tr ix s i tuat ion for d e c i d i n g 
implementation of chemical control 
In the middle of the dry season, there is always a mixed population of 
several generations of Tortrix, live caterpillars of different sizes, carcasses 
of dead caterpillars the pupae, the emerged pupal cases and masses of 
Macrocentrus cocoons. 
27 
CHEMICAL CONTROL OF TEA PESTS 
Tortrix adult Macrocentrus cocoon 
Also, the outbreaks in the middle of dry season are not in small pockets. 
Affected areas are large, spread over a few hundred bushes or whole 
fields. Therefore it is advisable to carry out an assessment before 
attempting to control mid-season outbreaks. The following procedure can 
be adopted to make an assessment before deciding the control measures 
i.e. chemical spraying. This will help in minimizing use of chemicals. 
28 
INSECTICIDES 
Divide the tortrix affected field into blocks in such a way 
each block having uniform visual symptoms 
I 
Select 5 bushes 
randomly per block 
1 
Collect all leaf nests, caterpillars, tortrix egg masses, Pupae, 
Macrocentrus cocoon masses and dead caterpillars of the 5 bushes into one bag 
1 
Sort out the collection and 
count as follows 
1 1 
Group 1 
All Caterpillars 
(larvae) 
Group 2 
Healthy pupae, 
fresh egg masses 
Group 3 
Empty/abandoned nests, 
Macrocentrus 
cocoon masses, 
dead empty pupae. 
1 1 1 
A 
Healthy larvae less than 
2.5 cm long 
D 
Healthy pupae and 
pre - pupal stage 
F 
Empty/abandoned nests 
I I 1 
B 
Healthy larvae more than 
2.5 cm long 
E 
Fresh egg masses 
G 
Macrocentrus cocoon 
masses 
1 1 
C 
Unhealthy and dead larvae 
H 
Dead/empty pupae 
Decision making for chemical control: 
• If Group 3 is in the majority; spraying not necessary. 
• If Group 2 is in the majority; vigilance should be maintained for new/next tortrix 
generations. 
• If Group 1 is in the majority; count A, B and C separately, if A is more than 50% 
of the collection, then chemical control is warranted. 
29 
CHEMICAL CONTROL OF TEA PESTS 
Fenthion (Lebaycid 5 0 % EC) 
Fenthion is a persistent insecticide with systemic/contact/stomach/ 
respiratory poisoning action. It is used against shot-hole borer. Also it 
could be used for the control of leaf miners, mealy bugs, aphids and scales. 
Chemical spray for shot-hole borer is carried out as a prophylactic measure. 
Chemical control of shot-hole borer in new clearings: 
As a prophylactic measure and in order to facilitate good frame 
development, all new clearings located in areas prone to shot-hole borer 
infestation should be annually treated with fenthion 50% during the first 
cycle. Chemical should be sprayed on the frame and stems. 
Spraying is recommended in May/June in the North-East sector and in 
December/January in the South-West sector. 
Dosage and spray volume: 3.5 L of Fenthion 50% EC in 750 L of 
water per hectare per application. (2.5 pint per acre in 67 Vi gal water) 
use only knapsack sprayers. 
Dilution rate for tank mixing: 4.7 ml of Fenthion 50% EC per 1 L of water. 
Frequency of application: A repeat spray is necessary after six to eight 
weeks in fields where borer attack have already been noticed. 
Chemical control of shot-hole borer in mature tea: 
The basal frames of the bushes should be sprayed with Fenthion 50% EC 
using knapsack sprayers after pruning. 
Spray should not be directed on the foliage. 
Dosage and spray volume: 4.5 L of Fenthion 50% EC in 1000 L of 
water per hectare, per application. 
Dilution rate for tank mix: 4.5 ml of Fenthion 50% EC per L of water 
30 
Sector Time of Time of spray Repeat 
pruning application application 
South-West April/May January following year 
(8-9 months after pruning) Not necessary 
South-West September/ January of the year after next 
October (15-16 months after pruning) Not necessary 
North-East March/April May of the following year 25-26 months 
(13-14monthsafterpruning) after pruning 
North-East September/ May of the year after Not necessary 
October the next (19-20) 
Diazinon Flowable 
Diazinon is a non-systemic insecticide with contact, stomach and respiratory 
action. It has acaricidal property as well. "Diazinon Flowable" formulation 
is recommended to control ant pests of tea lands. The formulation contains 
50 micron diameter capsules and can be used at a dilution of 1% a.i. 
spray mix by diluting with water. 
In mature tea, the base of the frame (trunk) including the ground around 
the base (covering a radius of 37 cm/15 inches) should be sprayed. In 
case of black ant species in nurseries, a blanket spray over the bed is 
recommended. Repeat application is not necessary. 
31 
CHEMICAL CONTROL OF TEA PESTS 
Carbosulfan CR/Controlled Release (Suscon Fore or Marshal 
Suscon) 
This is a slow release formulation which remains active in the soil for a 
long period (2 years). It acts on insects by systemic stomach/contact 
action. Controls white grubs in tea. Also, this can be used for the control 
of scavenging termites in fuel wood clearings. 
White grub control in tea: 
Add 1.5-2 g per plant. The granules should be thoroughly mixed with soil 
in the planting hole before planting giving envelope coverage to the root 
system. 
Scavenging termite control in fuel wood clearings: 
10 g should be thoroughly mixed with soil in the planting hole before 
planting. 
Imidachloprid (Admire SL 200, Gaucho 70) 
This is a systemic insecticide with contact and stomach action. It controls 
sucking insects including aphids, thrips and scavenging termites. 
Dosage and spray volume: For scavenging termites, it can be used as 
a short term palliative measure. 1.25 L - 2 L per hectare in 1250L-2000 
L of water (0.1 % dilution), 
32 
GUIDE TO IDENTIFY MAJOR INSECT 
PESTS OF TEA 
af 
id and 
Fringed Nettle Grub Macroplectra nararia 
Syn {Darna nararia) 
• Leaf cater with urticating spines on its 
body. 
• In advanced stage, bushes become 
denuded. 
• I )r\ weather pest common in I \ a. 
• ('an cause a total crop loss. 
33 
CHEMICAL CONTROL OF TEA PESTS 
Shot-hole Borer 
CXyle bonis for meatus) 
• Black colour small beetle wood 
borer. 
• Breakage of primary & secondary 
branches. 
• Shot-hole like galleries inside the 
branches. 
• Prevalent in the Low, Mid and I "p 
country. 
Low-country Live Wood Termites 
(Glyptotermis dilatatus) (Neotermes greeni). 
• Stem wood feeders on mature tea. 
• Galleries start from prune cuts extending 
down to the collar. 
• Hollowing out the bush frame. 
• Wilting browning of branches in dry 
weather. 
• Prevalent in Low country. 
Up-country Live Wood Termite 
(Postelectroterm es m ilitaris) 
• Root and Stem feeder. 
• Excavate galleries from roots up to 
branches. 
• Hollowing out the bush frame. 
• Branches wilt during dry periods. 
• Common in Maskeliya & Dimbula areas 
(Up-country). 
34 
GUIDE TO IDENTIFY MAJOR INSECT PESTS OF TEA 
s 
White Grubs/Cockchafers 
(Holotrichia disparilis and 
Microtrichia costata) 
Root feeders. 
"C'shaped white cream colour body 
with brown head. 
Plants wilt, defoliate and die. 
Absence of feeder roots, ring barked 
collar. 
Common in Up Mid country & in Uva. 
35 
AcARICIDES/MlTICIDES 
Propargite (Omite 57E) 
Propargite acts on mites predominantly by contact action and stomach 
poisoning. Also, it kills mites by fumigant action. It is used for control of 
all mite pests in tea. 
Dosage and Spray Volume: 1 L per hectare in 600 - 900 L water (15 oz 
per acre in 54 - 81 gal water) using knapsack sprayer. 
Dilution rate for tank mixing: 1.7 ml in 1 -1.5 L water. 
1L per hectare in 200 - 250 L water (15 oz per acre in 18-22 Vi gal water) 
using mist blowers. 
Dilution rate for tank mixing: 5 ml in 1 - 1.25 L of water using mist 
blowers. 
In the case of scarlet mite, spray the under surface of the foliage as well. 
Spraying should be done immediately after plucking. 
Frequency of application: Repeated application may be necessary when 
mites reappear. 
Pre harvest interval/resting period: Minimum of 2 weeks. The flush 
collected in the third week should be bulked with 10 times the amount of 
flush from unsprayed areas. 
36 
ACARICIDES/MlTICIDES 
Sulphur (Haymite 80% WP, Kumulus S 80% WP, Sofril 81 % WP, 
Sulphur80% WP,Thiovi t80% WP) 
Sulphur controls all mite pests in tea inclusive of the recently encountered 
pink mite by contact and vapour action. It is recommended for nursery 
plants and young tea areas that are not brought into plucking and also for 
rested tea areas. Sulphur spraying is not advised for tea in plucking, as it 
imparts a taint to made tea. In addition to the acaricidal properties it has 
fungicidal property too. 
Dosage and spray volume: 3- 4.5 kg per hectare in 600-900 L water 
(36 oz in 54 gal water per acre) by using knapsack sprayer. 
1-1.25 kg. per hectare in 200-250 L water (12 oz in 18 gal water per acre) 
using mist blowers. 
Dilution rate for tank mixing is 5 g sulphur 80% WP in 1 L water both for 
knapsack and mist blower spraying. 
Pre-harvest interval/resting period: 2 weeks is necessary. Although 
sulphur is relatively/practically non toxic to humans and animals it can 
taint tea up to 4 weeks of spraying. At the 3 r d week, the flush treated with 
sulphur can be bulked with untreated flush, at the rate of 1 part treated 
flush with 10 parts untreated flush. 
For scarlet mites, spraying should be done on the under surface of the 
leaves as well. 
37 
GUIDE TO IDENTIFY MAJOR MITE 
PESTS OF TEA 
Red Spider Mite 
(Oligonychus coffeae) 
• Leaf sucker, present on the upper side 
of maintenance leaves. 
• Reddish bronzing of upper surface of 
the leaf. 
• White dust & fine web of silken 
threads on the leal'. 
• Diy weather pest in Uva, High & Mid 
elevations. 
• Can cause defoliation & severe crop loss. 
Scarlet Mite 
(Brevipalpus californicus) 
• Leaf sucker, present on under side of 
maintenance leaves, more along petiole and 
midrib. 
• Dark brown necrosis on under side of midrib 
and petiole. 
• Discoloration of foliage and defoliation. 
• Dry weather pest in Up country and Uva. 
Purple Mite (Calacarus carinatus) 
• A leaf sucker on upper leaf surface 
of maintenance foliage. 
• Dull matt appearance of leaves 
followed by purplish tinge. 
• Characteristic dusty appearance of 
leaves. 
• Dry weather pest in Uva and 
Upcountry areas. 
38 
GUIDE TO IDENTIFY MAJOR MITE PESTS OF TEA 
Pink Mite 
(Acaphylla theae) 
• A leaf sucker on young 
maintenance foliage. 
• Affects both sides of leaf, tender 
stem and petiole. 
• Fine dust on the leaf surfaces, veins 
& margins turn pinkish. 
• Dry weather pest in Up Mid 
country and Uva. 
Yellow Mite 
(Hemitarsonemus latus) 
• Leaf sucker, present on underside of 
tender leaves. 
• Fine dust (mites) on underside of leaves. 
• Corky-brown necrotic stripes over and 
on either side of midrib. 
• Prevalent in I "\ a, N lid and I "p elevation. 
39 
NEMATICIDES 
Phenamiphos (Nemacur 5% G) 
Phenamiphos is an organophosphorus nematicide. This is a persistent 
systemic nematicide with contact action. Absorbed by the roots, with 
translocation to the leaves. It controls ectoparasitic, endoparasitic, free-
living, cyst-forming and root knot nematodes. 
Carbofuran (Furadan 3G, Cureturr 3 G) 
Carbofuran has both insecticidal and nematicidal properties. In tea, it is 
recommended as a nematicide. It is a systemic chemical with predominantly 
contact and stomach poisoning action. 
Dosage of the nematicides for nematode control in young tea 
7 g (1/4 oz) of any of the above granular nematicides per plant at the time 
of planting. The granules should be mixed with the soil in the planting hole 
for the roots to get an envelope coverage. 
Quantity required per hectare of new clearing: 88 kg. per hectare 
(78 lb per acre): on the basis of 12500 plants per hectare. 
Azadirachtin (Neemazal 1 % TS) - a natural pesticide 
Azadirechtin is basically an insecticide and also shows nematicidal and 
fungicidal activity. Mode of action is by way of disrupting insect moulting. 
Natural neem extracts can be used for pest control in tea. Neem extracts 
also show anti-feedant and repellent properties. 
Azadirechtin (Neemazal 1% TS) can be used for nematode eradication in 
infested young tea. 
Dosage and Dilution: 1 L per hectare in 600 L of water. 
40 
GUIDE TO IDENTIFY NEMATODE 
PESTS OF TEA 
Root Lesion Nematode (Pratylenchus loosi) 
Burrowing Nematode (Radopholus similes) 
• Eel shaped root parasites 
• S United unthrifty plants with dull pale yellow 
leaves 
• Premature flowering and fruit set 
• Necrotic patches on roots 
• Common in High and Mid elevations 
Affected root 
• * \ 
41 
SOIL FUMIGANTS 
Eradication of nematodes in nursery soils 
(Fumigation of nursery soils) 
Nurseries are the usual focal points of spread of nematode infestation to 
hitherto uninfested areas in the field. Once introduced into a field where 
conditions are conducive for further build up, it is impossible to eradicate 
these pests. Therefore, it is essential to take necessary steps to prevent 
nursery plants getting infested. 
Chemical treatment by soil fumigation is the most effective means of 
eradicating this pest. Therefore, soil collected from all elevations should 
be routinely fumigated. 
Despite marginally escalating the cost of nursery plants, soil fumigation 
that is carried out as a measure of insurance against possible nematode 
contamination, has a further distinct advantage, in that this treatment has 
a boosting effect on the growth of young nursery plants, resulting in healthy 
robust plants that have a good chance of early establishment in the field. 
Dazomet 9 8 % G (Basamid) 
Dazomet 98% G is recommended for fumigation of nursery soils to 
eradicate nematodes as described above. This is a micro granular soil 
fumigant. 
On contact with soil moisture, Basamid Granular is transformed into active 
compounds, mainly MITC (methyl isothiocyanate) which penetrate the 
spaces between soil particles. The gases clean up the soil by destroying 
fungi, bacteria, nematodes and other soil pests, living plants and seeds. 
42 
SOIL FUMIGANTS 
MITC gas possess nematicidal, fungicidal, insecticidal and herbicidal 
properties. 
Dosage: 500 g Dazomet 98% G per 2.8 cubic m (1 cube) of nursery soil. 
Soil heap of 2.8 cubic metre or 1 cube or 100 cubic feet 
Method of Dazomet application (Fumigation): 
Step i Make each cube of the sieved soil (2.8 cubic m) as a flat heap of 
about 0.3 m (1ft) high. 
3.2 m (10 ft) 
43 
CHEMICAL CONTROL OF TEA PESTS 
Step ii Apply Spread 500 g of Dazomet over the heap uniformly. 
Step iii Mix the soil thoroughly with the Dazomet to get a uniform mix. 
Step iv Apply sufficient water to the heap evenly to moist the soil (this is 
to initiate the active gas formation which will act on nematodes). 
44 
SOIL FUNUG ANTS 
Step v Level the top of the heap, cover by thatching with a grass like 
Guatamala Mana and leave it for 2 weeks. 
During this period Dazomet granular is transformed into active 
gases (compounds) which penetrate the spaces between soil 
particles. The gases (MITC) clean up the soil by destroying 
nematodes, fungi, bacteria and other soil pests, living plants and 
seeds. 
Step vi After two weeks, remove the thatch and turn the soil, thereafter 
again turn the soil three times at weekly interval (This is to release 
the toxic gases entrapped in the soil). 
Total duration of fumigating the soil with Dazomet is 5 weeks. Treated 
soil can be used for planting the cuttings after five weeks. 
45 
CHEMICAL CONTROL OF TEA PESTS 
Nursery beds should also be treated with Dazomet 9 8 % g at least two 
weeks before stacking the soil filled polythene sleeves. The granules 
could be broadcasted on nursery beds and dibbled into the soil at the 
rate of 10 g per sq. m. Treated beds are watered and thatched. 
M e t a m Sodium (Metham) 
Metam Sodium is a highly water soluble liquid fumigant which has 
nematicidal, fungicidal, insecticidal and herbicidal properties and used for 
control of certain soil borne pests. When applied into soil it rapidly converts 
to methyl isothiocynate (MITC) upon contacting moist soil. MITC, the 
active ingredient is a highly volatile and poisonous gas that fumigates soil 
borne pests. Metam Sodium can be used for fumigation of nursery soil to 
eradicate nematodes. 
Dosage for fumigation of nursery soil: 400 ml of Metam Sodium per 
1/4 cube (25 cubic feet) of soil. Please contact the TRI for details on 
method of application fumigation. 
46 
FUNGICIDES 
Copper Fungicides 
Copper fungicides are contact in their action. When sprayed, copper 
deposited on the leaf surface prevents the germination of fungal spores, 
thereby preventing infection. Copper will have no effect after fungus has 
penetrated the leaf surface. The main ingredient of copper fungicides is 
metallic copper (Cu) and is available in many forms and for tea, oxides, 
oxychlorides or hydroxides are recommended. Formulations could be either, 
wettable powders (WP) and dry flowable powders (DF). All TRI 
recommendations are based on copper formulations having 50% copper 
(W/W). Following copper fungicides are recommended for the control of 
Blister Blight disease. 
Copper oxide 50% WAV (Copper Sandoz, Perenox) 
It is an inorganic compound (CuO). Reddish in colour, insoluble in water, 
relatively heavier than other copper fungicides. 
Copper oxychloride 50% WAV (Cobox, Coblite, 
Copper oxychloride, Helmoxy) 
It is an inorganic compound (Cu 2Cl (OH) 3. Green to bluish-green colour 
powder. Practically insoluble in water. 
Copper hydroxide 50% WAV (Champion, Kocide 101) 
It is an inorganic compound; Cu(OH) 2 This has bactericide action as well. 
It is blue-green in colour and slightly soluble in water. 
47 
CHEMICAL CONTROL OF TEA PESTS 
Systemic Fungicides 
These are of relatively recent origin. Systemic fungicides have both 
protective and curative properties. Unlike the protectant fungicide, they 
can cure an established infection. Chemically they all belong to the group 
"triazoles". Following are the recommended systemic fungicides for tea. 
1. Bitertanol (Bacor 300 EC) 
2. Propiconazole (Tilt 250 EC, Bumper) 
3. Hexaconazole (Contaf-5E, Shakthi) 
4. Tebuconazole (Folicur 50% WP) 
The disadvantages of these fungicides are the high costs for the chemical, 
potential residues in made tea and the likelihood of the fungus developing 
resistance to the fungicide. But the latter could be overcome by adopting 
the following strategies: 
i. Using the lowest possible concentration of fungicide as 
recommended by the TRI. 
ii. Alternating the use of systemic fungicides with protectant 
copper fungicides. 
iii. Limiting the total number of applications per season to a 
minimum possible. Cumulative total of 20 hours sunshine over 
the previous five days is sufficient to prevent disease reaching 
an economic damage level, thereby one round of spraying 
can be skipped. 
iv. Whenever possible, use fungicides that belong to different 
groups possessing different modes of action. 
Note : Use of systemic fungicides in plucking fields is suspended 
at present. Contact TRI for more details. 
48 
FUNGICIDES 
Chemical control of blister blight in tea nurseries 
Nursery tea plants are maintained under shade and humid conditions and 
as a result, they are susceptible to infection most of the time. Hence, it is 
necessary to apply fungicides frequently to protect young plants. 
Use the following rates for 30,000 nursery plants (approximately 250 m 2 
area): 
Copper fungicides, sprayed at 4-day intervals 
Copper oxide and Copper Oxychloride: 120 g in 45 L of water (4 oz in 10 
gallons of water). 
Copper Hydroxide : 90 g in 45 L of water (3 oz in 10 gallons of water). 
Systemic fungicides, sprayed at 10- day intervals 
Baycor, Folicur, Tilt, Contaf, and Bumper at the rate of 25 ml in 45 L of 
water. 
Chemical control of blister blight in young tea and tea recovering 
from pruning 
Young Tea 
Tender young tea plants are prone to heavy attacks of Blister Blight. 
Repeated heavy infections could seriously damage newly established plants. 
Hence, closer rounds of fungicide spraying are recommended. Use only 
knapsack sprayers in order to better wet all the young foliage and stems 
properly, for maximum protection. 
49 
CHEMICAL CONTROL OF TEA PESTS 
Tea recovering from prune 
During this period, tea plants are very susceptible to blister blight attack 
as all the leaves and stems are young and tender. The loss of newly 
emerging shoots at this stage will cause a serious set back to growth, as 
food reserves in the bush at this period is inadequate for re-generation of 
new shoots. If the pruned bushes are not adequately protected against 
blister blight, it could lead to poor recovery which may even lead to death 
of bushes. 
Dosage, spray volume and spraying schedule for blister blight 
control both in young tea and tea recovering from prune 
Fungicide Dosage Spray volume/dilution Spray 
interval 
Knapsack Mist 
sprayer blower 
Contact fungicides 
Copper Oxide or 420-560*g/ha 170 L water/ha - 4-5 days 
Copper Oxychloride (6-8 oz/ac) (15 gal/ac) 
50% W/W 
(Copper Sandoz, 
Perenox, Cobox, Coblite, 
Copper oxychloride, 
Helmoxy) 
Copper Hydroxide 50% 320-420*g/ha 170 L water/ha 4-5 days 
W/W (5-7 oz/ac) (15 gal/ac) 
(Champion, Kocide 101) 
Systemic fungicides 
Bitertanol, Propiconazole 85 ml ha 170 L water/ha 4-5 days 
Hexaconazole, (1.25 fl oz/ac) (15 gal/ac) 
Tebuconazole 
* Note: The lower rate of copper fungicides are for normal monsoon 
conditions and the higher rates 560 g/ha and 420 g/ha are for heavy misty 
and cloudy weather conditions. 
Use of mist blower is not advised in young tea and tea recovering from prune. 
50 
FUNGICIDES 
Chemical control of blister blight in plucking fields 
Knapsack Sprayers or Mist-Blowers could be used for the spraying of 
fungicides in plucking fields. Spray immediately after plucking or on the 
day following. 
Dosage, spray volume and spraying schedule for blister blight 
control in plucking fields 
Fungicide Dosage Spray volume/dilution Spraying 
interval 
Knapsack Mist 
sprayer blower 
Contact fungicides 
Copper Oxide or 
Copper Oxychloride 
50%W/W 
(Copper Sandoz, 
Perenox,Cobox, 
Coblite, 
Copperoxychloride, 
Helmoxy) 
280420*g/ha 
(4-6oz»ac) 
r70Lwater/ha 
(15gal/ac) 
40 L water/ ha 
(3.5 gal/ac) 
7-10days 
Copper Hydroxide 50% 
TOW 
(Champion, Kocide 101) 
220-320*g/ha 
(3-5ozac) 
nOLwater/ha 
(15galac) 
40 L water/ha 
(3.5 gal ac) 
7-10days 
Svstemic fungicides 
Bitertanol, Propiconazole 
Hexaconazole, 
Tebuconazole 
85 ml/ha 
(1.25floz/ac) 
170 L water/ha 
(15galac) 
40Lwater/ha 
(3.5 gal ac) 
10-14days 
* Note: The lower rate of copper fungicides are for normal monsoon 
conditions and the higher rates 420 g/ha and 320 g/ha are for heavy 
misty and cloudy weather conditions. 
Pre-harvest interval: 7 days for copper fungicides and 14 days for 
systemic fungicides. 
51 
CHEMICAL CONTROL OF TEA PESTS 
Prevention of fungus building up resistance to systemic fungicides 
Due to the continuous use of systemic fungicides, the fungus could develop 
resistance against such fungicide. This can lead to a condition where 
particular fungicide becoming ineffective on the disease any more. 
Therefore, continuous spraying of a given systemic fungicide should be 
avoided. Instead, alternating spraying rounds of the systemic fungicide 
with a copper fungicide or mixing the systemic fungicide and copper 
fungicide each at half recommended dosage and spraying is advised. This 
manner of spraying helps to restrict the systemic fungicide usage. The 
following spraying programme could be adopted to overcome the problem 
of resistance build up. 
In young tea and tea recovering from prune 
1. Alternating the rounds of systemic fungicide with copper fungicide: 
Systemic . 
Fungicide 
10 days Copper 
Fungicide 
4-5 days 
^ 
Systemic 
Fungicide 
10 days 
^ 
Copper 
Fungicide 
• w 
4-5 days 
OR 
2. Mixing half the dose: Mix half the recommended dose of systemic 
fungicide and half the recommended dose of copper fungicide, using 
same amount of spray volume. Apply at 10-day interval. 
52 
In plucking fields 
1. Alternating the rounds of systemic 
fungicide: 
Systemic 
Fungicide 
2 weeks 
Copper 
Fungicide 
1 week 
Systemic 
Fungicide 
2 weeks 
Copper 
Fungicide w w 
1 week 
OR 
2. Mixing half the dose: Mix half the recommended dose of systemic 
fungicide and half the recommended dose of copper fungicide, using 
same amount of spray volume. Apply at 10-day interval. 
Some tips for efficient chemical control of blister blight 
1. Use fungicides that belong to different groups, possessing different 
modes of action. 
2. Limit the total number of applications per season to a minimum 
possible by following sunshine hours. Cumulative total of 20 hr 
sunshine over the previous 5 days is sufficient to prevent disease 
reaching an economic injury level. Thereby it would be possible to 
skip the spraying round that falls next to a 20-hour sun shine period. 
3. Train the spraying gang to acquire necessary knowledge and skill in 
spraying. 
4. Good protection depends on good supervision. 
5. It is important that the recommended amount of fungicides be sprayed 
on to the stipulated area for effective control. 
6. Spraying during continuous heavy rain is not warranted because there 
is less likelihood of infection as the spores too could get washed off 
along with the fungicide sprayed. 
53 
CHEMICAL CONTROL OF TEA PESTS 
7. Cool humid weather with overcast sky is very conducive for infection 
and spraying is best carried out during such periods. During light 
drizzles, spraying could be undertaken when they are not likely to 
wash off the fungicides from leaves. 
8. For better adherence of the chemicals on the leaf surface a sticker 
could be used. 
9. Spray equipment should be periodically checked and maintained in 
good condition. 
10. Wettable powders should be first made into a paste with a little water 
and then diluted to the required volume. 
Systemic fungicides for red root disease (Poria) 
Systemic fungicides could be used for treatment of the peripheral bushes 
of infected area/patches and for the treatment of infills after uprooting 
and clearing the Poria infested bushes. 
Treatment of peripheral bushes 
After the infected area has been thoroughly cleaned, the two rows of 
bushes surrounding the patch should be treated with a soil drench of a 
suitable fungicide directed at the area around the collar of bushes using a 
suitable fungicide at 300-350 ml per bush. They should be applied when 
the soil is sufficiently moist. Repeated applications at 2-3 month intervals 
up to 3-4 times must be undertaken depending on the performance of 
peripheral bushes. Care should be taken to avoid surface run off at the 
time of drenching treatment. The soil around the plants should be loosen 
with a hand fork before treatment. One of the following fungicides is 
recommended. 
Bitertanol (Baycor 300 EC): 0.3% (30 ml in 10 L of water) 
Hexaconazole (Contaf 5EC): 0.2% (20 ml in 10 L of water) 
Propiconazole (Tilt 250 EC): 0.2% (20 ml in 10 L of water) 
Tebuconazole (Folicur 250 EW): 0.2% (20 ml in 10 L of water) 
54 
FUNGICIDES 
Treatment of infills 
At the end of rehabilitation period, the patch could be planted with tea 
immediately followed by drenching fungicide treatment. The rate of 
application in the first two rounds (at 2-3 month intervals) can be at the 
rate of 250 ml per plant which should be increased up to 300-350 ml per 
plant in the subsequent two rounds, using one of the following fungicide 
solutions at the concentrations indicated below; 
Bitertanol (Baycor 300 EC): 0.3% (30 ml in 10 L of water) 
Hexaconazole (Contaf 5EC): 0.2% (20 ml in 10 L of water) 
Propiconazole (Tilt 250 EC): 0.2% (20 ml in 10 L of water) 
Tebuconazole (Folicur 250 EW): 0.2% (20 ml in 10 L of water) 
Clearing of Poria patches should be started two years prior to pruning, so 
that the vacancies can be infilled in the pruning year. 
Systemic fungicides for stem and branch canker in the Low country 
Use of Bitertanol (Bacor 300 EC) together with the recommended cultural 
methods is found to be effective to reduce stem and branch canker 
incidence. 
Dilution rate: 5 ml in 10 L of water (0.05% spray solution) 
In new clearings the fungicides should be applied with a knapsack 
sprayer, from the time of planting, once in 2-3 months, up to the time of 
the first prune. The plants should be given a drenching spray. As the 
plants get bigger, care should be taken to see that the developing branches 
are also sprayed. 
The pruned bushes should be sprayed with a fungicide about three times 
once in 2-3 months, starting soon after the pruning operation. The fungicide 
should be applied with a knapsack sprayer, to wet the frames and 
branches thoroughly. 
55 
CHEMICAL CONTROL OF TEA PESTS 
Chemical control of black blight disease in the Low country 
In nurseries: 
In heavily shaded nurseries, the shade should be thinned out during periods 
of exceptionally high and continuous rainfall. With the first appearance of 
widespread leaf spotting, drench spray the plants with a Copper fungicide 
(50% W/W) at the dilution of 25 g in 10 L (4 oz in 10 gallons) of water, 
using knapsack sprayers. If the rain continues, a second spraying should 
be undertaken after a fortnight. 
In new clearings: 
1 kg of Copper fungicide (50% W/W) in 450 L of water per ha (1 lb in 40 
gal water per acre). Spraying should be carried out only when severe 
expression of the disease i.e. stem infection is noticed. It is not economical 
to spray large extents if only the leaf spotting is noticed. 
Chemical control of red rust disease in the Low country 
The Red Rust Disease is caused by an alga. As Red Rust is more often 
serious on weak plants strengthen the plants by adopting good agricultural 
practices to minimize the damage. 
Spraying is recommended for red rust disease control. Copper fungicides 
have provided very good results. For effective control, spray a Copper 
fungicide (50% W/W) solution of 0.25% (25 g in 10 L of water) about 
three rounds during the year. For young tea, the first spray should be 
applied in late April, the second about four weeks later in May, and the 
third, in June. For good control, it is essential to wet the green stems and 
the older wood with the spray solution, on which the alga is sporulating. 
For old tea, the first spray application should be given soon after pruning, 
the second at tipping and third about four weeks later. It is advisable to 
56 
FUNGICIDES 
remove all trailing peripheral branches during pruning. Full benefits of 
spraying can be achieved only if spraying is continued for two to three 
successive years. 
Chemical sp ray for horse-hai r blight 
After bush sanitation measures, hydrated lime can be sprayed at the rate 
of 10 kg in 50 L water on to the frames after each prune. About 1.000 L 
of spray solution is required for 1 hectare. If the fields are affected by 
floods, it can be sprayed soon after the Hoods recede, with either a copper 
fungicide (20 g in 10 L water) or an appropriate systemic fungicide (10 ml 
in 10 L water). 
Fungicidal wound dressing 
It is important to prevent infection of prune cuts (particularly large cuts 
and cuts with shot-hole borer galleries), wounds caused by stem and branch 
canker and sun-scorched wounds from entry of fungus that cause wood 
rot. If such rots are left neglected, it can gradually invade the primary 
frames leading to a serious debilitation of bushes. 
One of the following fungicidal wound dressing paints pastes can be used 
to treat the wounds (for stem and branch canker, Bitertanol can be applied); 
• Bitertenol Paint (Baycor 3PA) 
• Copper Oxychloride Sulphur + Linseed oil at 1:1 ratio 
• Kandasan 
These paints pastes are applied after pruning and cleaning the frame with 
a brush. 
57 
GUIDE TO IDENTIFY COMMON DISEASES 
OF TEA 
(ii IDE TO IDENTIFY COMMON DISEASES OF TEA 
Collar and Branch Canker 
(Phoiii ops is theae) 
• (Hulling of bark at the collar. 
• Plants turn yellowish and die. 
• New clearings arc affected. 
• Prevalent in I "p country. 
Stem and Branch Canker 
(Macrophoma theicola) 
• Sunken dark patches on branches, 
dead bark separates from wood. 
• Callus around the patches. 
• Weaken kill the branches. 
• Prevalent in I o\\ elevations. 
Red Rust Disease 
(Cephaleuros parasiticus) 
• Brick red orange colour patches, 
longitudinal cracks on steins. 
• Characteristic variegation with 
yellow white patches on leaf. 
• Prevalent in Lou countrj. 
59 
CHEMICAL CONTROL OF TEA PESTS 
Hypoxylon Stem Blight 
(Nemania diffusa) 
• Foliage on affected branches wilt and 
scorch. 
• Branches break off from the main frame 
due to soft wood rot. 
• Characteristic irregular shaped black 
encrustations. 
• Prevalent in High elevations. 
Thorny Stem Blight 
(Tunstallia aculeata) 
• Black thorny projections on the 
bark of mature branches. 
• Black lines and patches on the 
wood. 
• Branches; bushes die due to 
decay of main stems. 
• Prevalent in Up country. 
General Wood Rot 
• Decay of pruned branches on the 
bush. 
• Rotting of heart-wood in main 
frames. 
• Scavenging termites, saprophytic 
fungi attracted to the rot. 
• Rot can extend up to the collar. 
60 
Gi IDETO IDENTIFY COMMON DISEASES OFTEA 
Horse-hair Blight 
(Marasmius equicrinis) 
• Upward growth of fungal strands from 
the main stem & branches. 
• Blackish horse hair-like cords. 
• An entangle of fungal cords , 
crisscrossing the bush. 
• Prevalent in Low country . 
Root Diseases 
Above g r o u n d symptoms common to any root disease 
Yellowing of foliage followed by wilting and death of the bush or some 
times part of the bush 
61 
CHEMICAL CONTROL OF TEA PESTS 
S y m p t o m s in t he roo ts d u e to va r ious roo t diseases 
Black Root Disease 
(Rosellinia arcuata) 
• Initially white, then wooly black 
mycelium strands. 
• Small white, star shaped patches 
of mycelium on the wood, under 
the bark. 
• Prevalent in Mid and High 
elevations. 
Red Root Disease 
(Poria hypolateritia) 
• Initially white, soft and fluffy 
mycelium on the root. 
• Mycelium turns smooth dark red 
cords sheets and brittle. 
• Finally root become soft and 
watery. 
• Prevalent in Mid & High 
elevations. 
Charcoal Root Disease 
(Ustulina deusta) 
• Large whitish, fan shaped mycelial 
patches on the wood under the 
bark. 
• Appearance of black double lines 
permeating the wood. 
• More prevalent in High elevations. 
GUIDE TO IDENTIFY COMMON DISEASES OF TEA 
Brown Root Disease 
(Phellinus noxious) 
• Adherence of a crust of soil and 
gravel round the infested root. 
• White brownish mycelium on the 
wood surface under the bark. 
• Wood deve lop a honeycomb 
structure during latter stages. 
• Prevalent in all tea growing areas. 
White Root Disease 
(Rigidoporns m icroporus) 
• Stout, flat cords of mycelium on 
the root surface. 
• Cords run longitudinally and 
connect each other in a network. 
• Common in I .ow country. 
63 
HERBICIDES 
Under the Integrated Weed Management (IWM) in tea, some or all 
manual, chemical, cultural, ecological and biological methods are adopted 
in combination in a rotational manner. In IWM, the available know-how 
on weeds and their management are utilized in order to achieve cost 
effective and eco-friendly weed control. Use of herbicides has a major 
attribution to the weed management in the face of dearth of labour. It is 
also a time saving and a cost effective method. 
Broad categorization of herbicides 
Pre-emergent 
(Applied before weeds emerge) 
Post-emergent 
(Applied on growing weeds) 
e.g. Oxyfluorfen, Diuron 
Based on mode of action 
Contact Translocated or 
systemic 
Kills tissues of the plant on contact with 
herbicide. 
e.g: Paraquat, Glufosinate Ammonium. 
Herbicide is first absorbed by leaves/stem or 
roots & moves within plants and kills the 
plant. 
e.g.: Glyphosate, 2,4-D, MCPA. 
64 
HERBICIDES 
Some factors to be considered in chemical weed control 
Chemical weed control is a convenient and effective method among the 
various weed management techniques available. Unlike manual weeding 
with the use of implements, chemical weed control minimizes soil erosion 
and largely eliminates the loss of plant nutrients. However, precautionary 
measures should be adopted in the use of herbicides to avoid possible 
hazards to the crop, humans and the environment. 
For the effective use of herbicides ensure that they are applied when the 
weeds are in an active stage of growth (when weeds are tender and 8-10 
cm in height). Pre-emergent herbicides (e.g. Oxyfluorfen), could be applied 
to the bare soil prior to thatching. 
When using any herbicide, follow the recommendations given by the TRI 
as well as the instructions given in the label and ensure that the appropriate 
dosage and dilution are used. 
Do not depend on a single herbicide. The number of herbicide application 
rounds should be minimized by adopting other weed control methods on a 
rotational basis. Continuous use of a single herbicide can lead to a 
development of resistant weeds. Such resistant weeds can spread 
aggressively invading the field creating a situation where it is difficult to 
control them. 
Be vigilant about weed species that are not adequately controlled by the 
herbicide/s used. Such herbicide-resistant weeds necessitate manual 
removal to prevent their build up. 
65 
( 'IIHMII AI ('• v i R I n . T T i \ PESTS 
Avoid herbicidal spray drifting on to the tea, as this would result in 
defoliation and long-term harm to the crop. Spray drifting to the tea can 
be prevented by using a spray guard (See Advisory Circular No.WM3 on 
"Safe and Effective Use of Herbicides) 
Use of spray guard for herbicide spraying 
66 
HERBICIDES 
The following herbicides are recommended for tea depending on the type 
of weed and the growth stage of tea. The choice of herbicide would largely 
depend on the weed species present and the economics of using it. 
1. Oxyfluorfen 
2. Diuron 
3. Glyphosate 
4. Paraquat 
5. Glufosinate Ammonium 
6. 2,4-D 
7. MCPA 
Weeds that are practically difficult to control are known to be problematic 
weeds; They are 
1. Panicum repens (Couch) 
2 . Imperata cylindrica (Illuk) 
3. Borreria latifolia (Borreria) 
4. Spermacoce hispida (Getakola) 
5. Anredera cordifolia (Wild spinach) 
6. Clidemia hirta 
7. Commelina diffusa (Girapala) 
8. Wedelia trilobata (Arunadevi) 
Since all herbicides are harmful to the crop, environment, humans and 
animals, to varying degrees, they should be applied as directed and at 
such dosages as recommended by the TRI with necessary precautions. 
Paraquat 2 0 % W/V (Baurs Paraquat , Harcross Paraquat , 
Gramoxone) 
Paraquat is a foliage applied non-selective, contact herbicide. It is effective 
when applied on the growing weeds and is more effective on younger 
active weeds than older mature weeds. It controls broad-leaved and grass 
weeds. Paraquat causes scorch on the aerial parts of tea bush when the 
spray drift falls on the tea. Therefore, precautions should be taken to 
67 
CHEMICAL CONTROL OF TEA PESTS 
prevent spray drifting to tea. Use spray guards when spraying. Do not 
spray weeds growing through the tea bush. 
Spray 0.7 - 1.1 L in 550 L of water per ha. (9.5 - 15 fl oz in 50 gal of 
water per acre) for tea fields with a moderate weed infestation. 
Dilution rate for tank mixing: 1.3 - 2 ml in 1 L of water 
The following weed species are resistant to paraquat and, cannot be 
controlled successfully by spraying paraquat alone. Therefore, they must 
be controlled manually or by other suitable herbicides before they build up 
and become a problem. 
Paspalum conjugatum ( S:Paspalam thana, E: Bufflow grass) 
Borreria species (S:Getakola, T: Nathaichuri) 
Commellina species (S: Girapala, T: Amalai) 
Crassocephalum crepidioides (S: Kadupahara, T :Thandam pul) 
Panicum repens (S:Atora, T: Arugam pul, E: Couch) 
Imperata cylindrica (S: Illuk, T: Varli pul) 
Hedyotis species (S: Getakola, T: Awal thattukkodi) 
Erigeron sumatrensis (S: Sudana, T: Alawangu pul) 
Digitaria species (T:Arisi pul, T: Kandukkal pul) 
Cynodon dactylon (S:Heen atora, T:Hariyali, E: Bermuda grass) 
Anredera cordifolia (S: Wal nivithi, T: Pasalikodi, E: Indian spinach) 
2, 4-D, 5 5 % E.C. (w/v) or 7 3 % amine salt (w/v) (Weedone, 
Hedonol - D, Fernoxone, Weedkiller-D) 
2,4-D is a foliage applied selective systemic/translocated herbicide. Also, 
it has a limited residual effect. It is recommended for broad leaved weed 
species in tea as post-emergent control. 
Spray 1.7 - 2.8 L in 550 L of water per ha if 55% E.C. formulation is used. 
Dilution rate for tank mixing: 3 - 5.3 ml in 1 L of water. 
S.-Sinhala T: Tamil E: English 
68 
HERBICIDES 
Spray 1 - 2 L in 550 L of water per ha if 73% amine salt formulation is used. 
Dilution rate for tank mixing: 2 - 3.7 ml in 1 L of water 
2,4-D is also available in powder form as 73% sodium salt (w/v). 2,4-D 
is mainly used against Morning glory, Commellina species, Wedelia, 
Mikania and Poligonum. 
MCPA 4 0 % EC w/v (Agroxone, Baurs MCPA 4 0 % , Harcross 
MCPA 40%, Hedonol M 4 0 % , Weedem 400) 
MCPA is foliage applied selective, systemic/translocated herbicide. It has 
a limited residual effect (absorbed by roots). It is recommended for broad 
leaved weeds in tea. 
Spray 1.75 - 3 L in 550 L of water per ha. 
Dilution rate for tank mixing: 3.2 - 5.5 ml in 1 L of water. 
Particularly MCPA is used against Commellina, Borreria and Mikania. 
The following weed species can also be controlled with 2,4-D or MCPA 
Artemisia vulgaris (T:Marukolundu, E:Mug wort wort, 
Indian worm wood) 
Erigeron sumatrensis (S:Sudana, T: Alawangu pul) 
Eupatorium riparium (S:Ayapana, T:Poondu pul) 
Commellina diffusa (S:Girapala, T:Amali) 
Hedyotis species (S:Getakola, T:Awalthattukkodi) 
Achyranthus aspera (S:Karalheba, T:Naiyuruwi) 
Sida acuta (S:Gas Babila, T:Palampasi) 
Sida rhombofolia (S: Kotikan babila T: Sittrumudi) 
S:Sinhala T: Tamil E: English 
69 
CHEMICAL CONTROL OF TEA PESTS 
Diuron (Diuron 8 0 % WP, Harcross Diuron 80% WP) 
Diuron is a soil applied residual herbicide. It is a systemic herbicide, 
absorbed principally by the roots. Diuron should be applied to a relatively 
clean land or with a wetting agent when the weeds are very young. It is 
best applied on a clear day when the soil is moist. Do not apply frequently. 
A maximum of two applications per year is recommended. It kills 
germinating seeds and remains active in the soil over a period of time. 
Weeds such as Panicum repens, Crassocephalus crepidioides. 
Erigeron sumatrensis are resistant to Diuron. 
Diuron 80% W P (Harcross Diuron 80% WP): 
Mix 1.2 kg in 550 L of water and spray for one hectare (1.2 lb in 50 gal for 
one acre). 
Dilution rate for tank mixing: 2.2 g in 1 L water. 
The required quantity of the Diuron powder should be first made in to a 
paste with a little water and then mix this paste with the recommended 
quantity of water to prepare the spray mixture. This prevents clogging. 
The bulk spray mixture should be stirred well before charging the sprayer. 
Glyphosate (Barusate 36, Counter, Destroy, Glycel, Glycine, 
Glyphosate, Round up, Surpass, Weedol, Touchdown) 
Glyphosate is a foliage applied systemic/translocated non-selective herbicide. It 
is absorbed by the foliage and translocated rapidly. It kills the underground parts . 
of many weeds which are difficult to control by other herbicides. Glyphosate is 
available with a.i. content of 36% w/v, 35.5% w/v and 41 % w/w. 
Panicum repens (S:Atora, T: Aurgam pul, E: Couch grass) 
Imperata cylindrica (S:Illuk, T:Warli pul) 
Cyanodon dactylon(S:Heen atroa T:Hariyali E:Bermuda grass) 
Pennisetum clandestine (T:Kudhirai pul, E:Kikue grass) 
S:Sinhala T: Tamil E: English 
70 
HERBICIDES 
Isachne kunthiana (T:Moongi pul, E: Bamboo grass 
Pennicetum polystachion (S:Rila thana, E: Fox tail grass) 
Spray 1.4 - 2.8 L in 550 L of water per ha (0.25 - 0.5% solution). 
Dilution rate for tank mixing: 2.5 - 5.1 ml in 1 L of water. 
Do not pluck the tea for two weeks after spraying. 
Avoid spraying in new clearings and pruned fields. 
Glyphosate should be sprayed when the weeds are growing vigorously. 
Spraying should be done in bright weather and when it could be free of 
rain at least for six hours after spraying. Galvanized containers or galvanized 
sprayers should not be used for spraying. 
Oxyfluorfen 24% w/w Liquid (Goal 2E) 
Oxyfluorfen is a liquid soil applied pre-emergent residual herbicide. Mode 
of action is selective and contact. Recommended for young tea fields and 
pruned fields. It is effective on a wide variety of weeds. It remains active 
in the soil for a considerable period of time killing the germinating seedlings. 
Oxyfluorfen alone should be sprayed to the bare soil or with Paraquat 
when there are weeds in the land. It is best applied on a clear day and 
when the soil is moist. It is recommended for new clearings (before 
mulching), and pruned tea fields for the control of annual broad leaved 
weeds and grasses. A spray guard should be used when sprayed with 
Paraquat. 
Mix 1.2 L in 550 L of water per hectare (17 fl. oz in 50 gal of water per 
acre). Mix paraquat 750 ml per hectare (11 fl. oz per acre when there are 
weeds in the land. Oxyfluorfen is best applied on a clear day and when 
the soil is moist. 
Dilution rate for tank mixing: 2.2 ml in 1 L of water. 
S:Sinhala T: Tamil E: English 
71 
CHEMICAL CONTROL OF TEA PESTS 
Glufosinate Ammonium 15% w/w Liquid (Basta 15%) 
Glufosinate Ammonium is a non selective, contact herbicide with some degree 
of systemic action. Translocation takes place only within leaves, mainly 
from leaf base to leaf tip. It is more effective on broad leaved weeds and 
perennial weed species. It is also effective on most of the weeds which are 
resistant to paraquat such as: 
Erigeron sumatrensis (S: Sudana, T: Alawangu pul) 
Crassocephalum crepidiodes (S: Kadupahara, T:Thandam pul) 
Commelina species (S: Girapala, T: Amalai) 
Spermacoce hispida (S: Getakola) 
Mix 1.3 L in 550 L of water per hectare. 
Tank mix: 2.3 ml in 1 L of water. 
Glufosinate Ammonium is not recommended for weed control in young tea 
fields. 
Mixing of different herbicides (Herbicide cocktail mixtures) 
When there is a mixed stand of weed species in a field, it is possible to mix 
two different kinds of compatible herbicides at the recommended rates. 
This practice reduces the cost of spraying. The mixing of herbicides should 
be decided depending on the type of weeds in the field. Different herbicides 
could be mixed only if they are compatible. 
The following herbicide cocktail mixtures can be used in tea: 
i. Paraquat + Diuron 
ii. Paraquat + Oxyfluorfen 
iii. Glyphosate + Oxyfluorfen 
iv. Glufosinate Ammonium + Oxyfluorfen 
v. Glufosinate Ammonium + Diuron 
vi. Glyphosate+2,4-D or MCPA 
Contact herbicides and translocated herbicides should not be mixed. 
72 
HERBICIDES 
Chemical control of some problem weeds 
The following weeds are considered to be problem weeds which are more 
difficult to control than in the case of other weeds in tea lands. 
Panicum repens (Couch Grass) 
Imperata cylindrica (Illuk grass) 
Borreria latifolia (Borreria) 
Spermacoce hispida (Getakola) 
Anredera cordifolia (Wal Nivithi) 
Wedelia trilobata (Arunadevi) 
The dosage and spray volume of herbicides to control these weeds 
are as follows: 
Couch Grass {Panicum repens) 
Glyphosate 11 L per hectare in 550 L water or 
Glyphosate 5.5 L + 3.4 kg of kaolin in 550 L of water per hectare. 
Dilution rate for tank mixing: 20 ml in 1 L of water or 
10 ml in 1 L of water + 6 g kaolin 
Couch grass which are growing within the bush frame should be pulled out 
and lay down before spraying. 
Illuk grass (Imperata cylindrica) 
Glyphosate 5.5 L per hectare in 550 L of water 
Dilution rate for tank mixing: 10 ml in 1 L of water. 
Tea should not be plucked until 2-weeks after spraying. 
Borreria (Borreria latifolia) 
MCPA (60% E C ) 1.2 L +paraquat (25% a.i.) 1.1. L in 550 L water per 
hectare as spot application. 
Dilution rate for tank mixing: MCPA 2.2 ml + Paraquat 1.1 ml in 1 L of 
water. 
73 
CHEMICAL CONTROL OF TEA PESTS 
Getakola ( Spermacoce hispida) 
Following mixtures could be given as spot application; 
Diuron (80% WP) @ 1.1 kg + Glyphosate (36%) 2.8 L in 550 L water/ha 
Dilution rate for tank mixing: Diuron 2 g + Glyphosate 5.1 ml in 1 L of 
water. 
or 
Diuron (80% WP) @ 1.4 kg + 2,4-D (55%E.C.) or MCPA 60% @ 1.2 L 
in 550 L water/ha 
Dilution rate for tank mixing: Diuron 2.5 g + 2,4D or MCPA 2.2 ml 
in 1 L of water. 
or 
Diuron (80% WP) @ 1.1 kg + Paraquat (20%) 1.1 L in 550 L water/ha 
Dilution rate for tank mixing: Diuron 2 g + Paraquat 2 ml in 1 L of water. 
or 
Glyphosate (36%) @ 3.5 L + Sulphate of Ammonium 2.8 kg in 550 L 
water/ha 
Dilution rate for tank mixing: Glyphosate 6.4 ml + Sulphate of Ammonia 5.1 
g in 1 L of water. 
Arunadevi (Wedelia trilobata) 
MCPA (60% E.C.) @ 1.5 L + Glyphosate (36% a.e.) 3.6 L 
in 550 L water /ha 
Dilution rate for tank mixing: MCPA 2.7 ml + Glyphosate 6.5 ml in 1 L of 
water. 
or 
MCPA (60% E.C.) alone @ 2.2 L in 550 L water/ha 
Dilution rate for tank mixing: MCPA 4ml in 1 L of water. 
Herbicide toxicity 
Haphazard and excessive use of herbicides can lead to phytotoxicity in tea 
bushes. The toxic effects are manifested in the form of Chlorosis of foliage, 
multiple shoot formation or rosetting, and wilting of peripheral branches. 
These result in retarded growth and diminish productivity of tea. 
74 
MISCELLANEOUS 
Hydratedlime 
Hydrated lime could be sprayed on the tea frame to check the growth of 
moss and lichen (Epiphytic growth). In addition, it helps to soften the 
bark and helps bud break and minimize sun scorch to bush frames. 
Hydrated lime is available in the form of powder. 
Mix 100 -125 kg of hydrated lime in 1000 -1250 L of water and give a 
soaking spray to the frame after pruning, with a knapsack sprayer. 
Spreaders/stickers 
Spreaders are surface active agents or dispersing agents. When they are 
added to a spray solution, it reduces the surface tension of spray drops 
and improves the wetting properties. Generally spreading agents are 
incorporated with pesticide formulations. However, it is advantageous to 
add a spreading agent to any spray solution especially when spraying on 
waxy and hairy leaved plants. 
Behaviour of a spray droplet on a waxy leaf surface 
without spreader with spreader 
75 
CHEMICAL CONTROL OF TEA PESTS 
Behaviour of a spray droplet on a hairy leaf surface 
Stickers contain a gum which helps to keep the sprayed solution glued to 
the plant surface. Hence it is advantageous to use stickers in rainy weather. 
Some spreading agents have properties of stickers as well. 
without spreader with spreader 
Example of spreaders: Soap, Teepol, Sandovit-N, Surfactant-N, Surpot, 
etc. 
76 
GUIDE TO IDENTIFY COMMON WEEDS 
IN TEA LANDS 
L 
Val Nivithi (S), Pasalikodi (T).Wild Spinach(E) 
Anredera cordifolia 
Perennial herb 
Propagate vegctatively (bulbils, yams, 
cuttings) 
Prevalenl in mid and high elevations 
Girapala (S), Amalai (T) 
Commellina diffusa 
Perennial plant 
Propagation, vegctatively and by seeds 
Prevalent in all elevations 
Getakola(S), Awalthattukodi (T) 
Hedyotis fruticosa 
Biannual plant 
Propagation by seeds 
Prevalent in all elevations 
Polkatu gas (S), Awalthattu kodi (T) 
Hedyotis srilankemis 
Annual plant 
Propagation by seeds 
Prevalent in the Low country 
S: Sinhala T: Tamil E: English 
77 
CHEMICAL CONTROL OF TEA PESTS 
Parpadagam pul (T) 
Spermacoce latifolia 
Annual plant 
Propagation by seeds 
Prevalent in the Low country 
Hulanthala (S), Poom pul (T), White weed (E) 
Ageratum conyzoides 
Annual herb 
Propagation by seeds 
Prevalent in all elevations 
Val batala (S), Pal kodi (T), 
Morning glory (E) 
Ipomoea indica 
Perennial plant 
Propagation by seeds or stem 
Prevalent in Up and Mid country and Uva. 
Karalheba (S), Nayuruvi (T), Prickly chaff (E) 
Achyranthus aspera 
Annual plant 
Propagation by seeds 
Prevalent in Low and Up country 
S: Sinhala T: Tamil E: English 
78 
GITDE TO IDENTIFY COMMON WEEDS IN TEA LANDS 
Kadupahara (S), Thandam pul (T), Thicket head (E) 
Crassocephalum crepidioides 
Annual plant 
Propagation by seeds 
Prevalent in Low, Mid and L'p country 
Heen Nidikmba (S), Thottachiningi (T), 
Sensitive Plant (E) 
Mimosa pudica 
Annual plant 
Propagation mainly by seeds 
Prevalent in Mid and LTp country 
Miyandalu (S), Polygonum (E) 
Percicaria capitata 
Annual plant 
Propagation by seeds 
Prevalent in Up country 
Sudana (S), Alavangu pul (T) 
Erigeron sumatrensis 
Annual plant 
Propagation by seeds 
Prevalent in all elevations 
S: Sinhala T: Tamil E: English 
79 
CHEMICAL CONTROL OF TEA PESTS 
Gas bavila (S), Palampasi (T) 
Sida acuta 
Annual perennial plant 
Propagation by seeds 
Prevalent in Mid and Low country 
Val te kola (S), Ottu pul (T), 
Spanish needle (E) 
Bidens pilosa 
Annual plant 
Propagation by seeds 
Prevalent in I Tp and Mid country 
Hulanthala(S), (T), (E) 
Eluthananthara rudaralis 
Annual plant 
Propagation by seeds 
Prevalent in the Low country 
Kadupahara (S) 
Emilia sonchifolia 
Perennial plant 
Propagation by seeds 
Prevalent in Mid and Up country 
S: Sinhala T: Tamil E: English 
80 
GUIDE TO IDENTIFY COMMON WEEDS IN TEJ 
Gandapana (S), Unnichchedi(T), Lantana(E) 
Lantana camara 
Annual plant 
Propagation by seeds 
Prevalent in all elevations 
Balu naguta (S), Nai urunchi (T), Blue rats tail (E) 
Stachytarpheta urticaefolia 
Perennial plant 
Propagation by seeds 
Prevalent in Low country 
Clidemia hirta 
Perennial plant 
Propagation by seeds 
Prevalent in Low country 
Atora (S), Arugam pul (T), Couch grass (E) 
Panicum repens 
Perennial grass 
Propagation: Rhizomes &seeds 
Prevalent in Mid and LTp country 
S:Sinhala T: Tamil E: English 
CHEMICAL CONTROL OF TEA PESTS 
Illuk (S), Varli pul (T) 
Imperata cylindrica 
Perannial grass 
Propagation mainly by rhizomes 
Prevalent in Mid and Low country 
Rila thana (S), Kolukattai pul (T), Foxtail grass (E) 
Pennisetum polystachion 
Perennial grass 
Propagation by rhizomes & seeds 
Prevalent in Up, Mid and Low country 
Bela thana (S), Tippa ragi (T), Goose grass (E) 
Elusine indica 
Annual semi perennial grass 
Propagation by seeds 
Prevalent in Mid and Low country 
Kalanduru (S), Korai kilangu (T), Purple nutsedge (E) 
Cyperus rotundas 
Perennial sedge 
Propagation mainly by rhizomes 
Prevalent in the Low country 
S: Sinhala T: Tamil E; English 
82 
83 
GUIDELINES FOR THE SAFE USE OF PESTICIDES 
Pesticides are not only toxic to the target pests but also toxic or hazardous 
to human beings, animals and the environment. (Hazard refers to the risk 
or danger of poisoning when a chemical is used or applied). 
Pesticides are grouped into categories based on the hazardness to man 
and animal as follows, (hazard group of some pesticides that are being 
used in tea is also indicated). 
Pesticide hazard category 
i. Extremely hazardous 
ii. Highly hazardous 
iii. Moderately hazardous 
iv. Slightly hazardous 
i. Extremely hazardous: 
Phenamifos, Carbofuran. 
ii. Highly hazardous: 
Carbosulfan, Diazinon, Fenthion, Paraquat. 
iii. Moderately hazardous: 
Copper oxide, Propargite, Propiconazole, 2,4-D. 
iv. Slightly hazardous: 
Copper hydroxide, Copper oxychioride, Dazomet, Glufosinate 
ammonium, Glyphosate, MCPA, Tebufenozide. 
Probable oral dose to kill an adult 
human 
a pinch to one teaspoon 
one teaspoon to two tablespoons 
30 to 470 ml (1 oz to 1 pint) 
470 to 950 ml ( 1 pint to 2 pints) 
84 
GUIDELINES FOR THE SAFE USE OF PESTICIDES 
Unlike to cause acute hazard in normal use: 
Bitertanol, Diuron, Hexaconazole, Oxyfluorfen, sulphur 
Granular pesticide formulations are safer to the user than spray formulations. 
This is why extremely hazardous pesticides are manufactured in granular 
form. 
Relative Toxicity Categories 
Mammals (people) 
Relative Toxicity Category Oral LD 5 0 
(mg/kg) 
Dermal LD 5 0 
(mg/kg) 
Slightly toxic >500 >1000 
Moderately toxic 51 -500 201 - 1000 
Very toxic 0 - 5 0 0 - 2 0 0 
Birds 
Relative Toxicity Category Acute Oral Toxicity 
(mg/kg) 
Dermal 
(mg/kg) 
Practically non toxic >2000 >5000 
Slightly toxic 501-2000 1001-5000 
Moderately toxic 51 - 500 501 -1000 
Highly toxic 10 -50 50 - 500 
Very highly toxic < 10 < 50 
85 
CHEMICAL CONTROL OF TEA PESTS 
B e e s 
Relative Toxicity Category Description 
Highly toxic Kills on contact during applica­
tion and for one or more days 
after. 
Moderately toxic Kills bees if applied over them. 
Can be used with limited danger 
to bees if not applied over bees in 
the field or hives. Correct dosage, 
timing and method of application 
are essential. 
Practically non toxic Relatively non toxic. Can be used 
with few precaut ions with 
minimum injury to bees. 
Fish 
Relative Toxicity Category mg/kg 
Practically non toxic > 100 
Slightly toxic 10 - 100 
Moderately toxic 1 - 10 
Highly toxic 0.1 - 1 
Very highly toxic < 0.1 
86 
GUIDELINES FOR THE SAFE U S E OF PESTICIDES 
Warning symbols 
Visual warning symbols on pesticide labels indicate the kind of harm that can 
result from pesticide misuse or mishandling. They alert the user to the degree of 
the hazard (by the shape of the border) and to the type of hazard (by the centre 
"Picture"). 
Poisonous 
The "skull and cross bones" symbol warns that the 
chemical is poisonous if taken into the body. Keep 
the product out of reach of children. Use the 
appropriate safety measures when dealing with 
poisonous products. 
Flammable 
The "fire" symbol is a warning that the pesticide is 
flammable or easily ignited. Keep the pesticide away 
from heat, sparks, or open flames. Do not smoke 
while mixing or applying the product. 
Explosive 
The "exploding grenade" symbol indicates that the 
pesticide can explode, e.g., pesticide in pressurized 
cans. Explosive conditions may also be created by 
using Glyphosate in a galvanized steel spray tank. 
Corrosive 
The "corroded hand" symbol indicates that the 
pesticide is corrosive to the skin and eyes. The 
chemical is either acid or alkali (caustic) and can 
burn the skin. Protect the skin and eyes when using 
these products. 
87 
CHEMICAL CONTROL OF TEA PESTS 
Toxicity Symbols 
Danger Poison 
LD 5 0 less than 500 mg/kg indicates high toxicity. 
Warning Poison 
LD 5 0500 to 1,000 mg/kg indicates moderate toxicity. 
Caution Poison 
LD 5 01,000 to 2,000 mg/kg indicates low toxicity. 
LD 5 0 greater than 2,500 mg/kg indicates very low 
toxicity. 
88 
GnniLiNius FOR m i ; SAFE USE OF PESTICIDES 
Pesticide poisoning 
Pesticide poisoining occurs when a pesticide enters the body. There are 
three main ways of poisoning. 
1. Orally: When nozzles are blown by mouth. 
Eating, drinking, chewing, smoking while spraying. 
Using empty pesticide containers for household purposes. 
2. Inhalation: when preparing the spray solution. 
When spraying against the direction of wind. 
When fumigating. 
When dusting. 
3. Dermal penetration: 
By handling the concentrate without wearing gloves. 
Stirring the spray solution w ith the hands. 
Spraying w ithout wearing protective clothes. 
Use of leaking sprayers. 
Hands, eyes, spine, throat, forehead, neck, chest, stomach and genital 
areas are vulnerable to dermal penetration. By using protective clothes, 
pesticide poisoning could be minimized. 
8<) 
CHEMICAL CONTROL OF TEA PESTS 
The symptoms of pesticide poisoning depend on the degree of poisoning. 
eyes, nose, throat & skin 
When one or more of the above symptoms are seen, the patient must be 
given first aid and rushed to the nearest hospital. First aid is extremely 
important: action taken during the first few minutes following and accident 
may mean life or death to the victim. 
1. Move the patient immediately away from the place of poisoning. 
2. Remove contaminated clothes and wash contaminated places of 
the body with soap and water. 
3. If the contamination has occurred on the head, wash the scalp and 
hair thoroughly. 
4. If the contamination had occurred in the eyes, wash with pure wa­
ter for 15 minutes. 
5. Keep the patient in a ventilated place. 
6. Do not make the patient get excited. 
7. If paraquat has entered through the mouth, make the patient vomit 
by putting two fingers down the back of the throat. If the patient is 
unconscious do not induce vomiting. 
8. If necessary give him/her artificial breathing. 
Take the label and/or the container of the pesticide with the patient 
to the hospital. 
Head ache 
Tiredness 
Diarrhoea 
Sweating 
Poor appetite 
Irritation in 
Minor poisoning Moderate poisoning High poisoning 
Vomiting Fainting 
Blurred vision Breathing diffculty 
High pulse rate Low pulse rate 
Breathing difficulty 
Cramps 
Nervousness 
90 
Store pesticides separately in a 
safe place and keep them locked. 
Wear gloves when handling the 
concentrate. 
Use protect ive wear while 
spraying. 
Carefully read the instructions on 
the label of the pes t ic ide 
container. 
Use a stick or a rod to stir the spray 
solution. 
Check the spray equipment for 
leakages before spraying. 
Keep a tool set with you in the 
field to attend to minor repairs. 
Wash all spray equipment clothes, 
etc., and bathe after spraying. 
Clean clogged nozzles with a thin 
wire or a pin or a thin grass stem. 
Bury empty pesticide containers. 
GUIDELINES FOR THE SAFE USE OF PESTICIDES 
:'S 
Do not store near food items and 
within reach of children. 
Do not spill the concentrate which 
may cause serious hazard to man, 
animal and environment. 
Do not eat, drink, chew or smoke 
while working with pesticides. 
Do not use empty pest ic ide 
containers for house-hold 
purposes. 
Do not use hands to stir the spray 
solution. 
Do not use leaking sprayers. 
Poisoning is possible through skin 
contact. 
Do not spray against the wind as 
it exposes you to the spray drift. 
Do not employ inexperienced 
workers for spraying. 
Do not blow into the clogged 
nozzles with mouth. 
Do not wash sprayers in water 
ways, wells, tanks etc. 
STANDARD SPRAY EQUIPMENT 
Insecticides, acaricides and fungicides are usually applied as foliar sprays 
while herbicides are sprayed either onto the weed foliage or the soil. The 
following types of sprayers are used in tea estates. 
1. Motorized Knapsack mist blower ( referred to as Mist blower 
in common use). 
2. Hand operated Knapsack sprayer (referred to as Knapsack 
sprayer in common use). 
Motorized knapsack mist blower 
This produces very fine spray droplets (50-100 micro metres). Mist blowers 
are used for low volume spraying, i.e. the recommended quantity of the 
pesticide is diluted in less amount of water and sprayed to the recom­
mended area. 
Mist blowers are not recommended for herbicide spraying at all and for 
other pesticide spraying unless recommended. 
92 
STANDARD SPRAY EQUIPMENT 
Hand operated knapsack sprayer 
Knapsack sprayers produce large droplets compared to mist blowers. The 
droplet size varies depending on the type of the nozzle used, the pressure 
applied and the discharge angle of the spray. 
The droplet size depends on (at a constant pressure & flow rate) 
Nozzle type 
Hollow cone nozzle produces 
Fan jet nozzle produces 
Solid cone nozzle produces 
very fine droplets 
fine droplets 
bigger droplets 
PohT Jet (Flood Jet) nozzle produces fairly larger droplets 
Discharge angle of the spray 
At low discharge angle At high discharge angle 
big droplets are produced small droplets are produced 
93 
CHEMICAL CONTROL OF TEA PESTS 
Pressure in the sprayer system 
Fine droplets are produced at high pressure 
Large droplets are produced at low pressure 
Discharge rate of a nozzle depends on 
Pressure in the sprayer 
Low pressure gives low discharge rate 
High pressure gives high discharge rate 
Size of the nozzle opening 
Smaller opening gives low discharge rate 
Bigger opening gives high discharge rate 
Rotation speed of the spray liquid in the nozzle body 
Lower rotation speed gives low discharge rate 
Higher rotation speed gives high discharge rate 
94 
STANDARD SPRAY EQUIPMENT 
Standard nozzles for herbicide spraying 
Green 'Polyjet' nozzles and Yellow 'Polyjet' nozzles are used for herbicide 
spraying in tea. Blue 'Polyjet' nozzles could be used in non tea areas like 
ravines, banks, limber clearing, etc., 
Green 'Polyjet' nozzle 
Spray swath up to 90 - 100 cm ( 3 ft). 
Suitable for young and mature 
tea fields. 
Yellow 'Polyjet' nozzle 
Spray swath up to 50 cm (1 Vi ft). 
Suitable for mature tea fields and for 
spot spraying. 
Blue 'Polyjet' nozzle 
Spray swath : up to 1.5 m (4 ft). | 
Suitable for non tea areas like 
ravines, road banks limber 
clearings, etc. 
V 
When spraying herbicides, maintain the tank pressure at a lower level at 
all times. This helps to avoid spray drifting on to the neighboring lea bushes 
and saves chemical by lowering the discharge rate. 
95 
CHEMICAL CONTROL OF TEA PESTS 
Standard nozzles for spraying 
fungicides 
Either hollow - cone nozzles or solid 
for insects, mites and diseases. 
Hollow - cone type nozzle 
Thi,s nozzle produces a 
circular (conical) pattern 
spray but no spray droplets 
in the centre. Produces very 
small droplets 
of insecticides, acaricides and 
cone nozzles are used when spraying 
Solid - cone type nozzle 
This nozzle produces a 
circular (conical) pattern 
spray which are evenly 
distributed over the circle. 
Produces larger droplets. 
96 
SOME USEFUL HINTS FOR EFFECTIVE SPRAYING 
1. Pesticide application is costly and causes hazard to man, animal and 
environment. Before undertaking spraying one must carefully assess 
the pest damage in the field and spray only when necessary according 
to recommendations. Pesticides may harm the predators and parasites 
which normally keep a pest species under control. Haphazard and 
frequent use of pesticides creates conditions in an organism which is 
a minor pest and can increase its number and also the pests can 
develop resistance to pesticides. 
2. A commercial pesticide formulation is a mixture of active ingredient 
and inert matter. Only the active ingredient kills pests; hence, the 
recommended quantity of active ingredient should be used to kill the 
pest. Therefore the person who undertakes spraying should be 
experienced enough to know the correct walking speed in order to 
cover the recommended area with the recommended quantity of the 
pesticide. If less than the recommended rate is used, the quantity of 
pesticide will not be sufficient to kill the pest. On the other hand 
applying more than the recommended rate will be a wastage of 
chemical. 
3. Timing of spraying plays a vital role in effective pest control, spraying 
should be undertaken when the pest is in the stage susceptible to the 
pesticide. Pests are easily controlled by spraying when they are young 
and actively feeding on the host. Weeds are susceptible to herbicides 
at young and actively growing stage. Therefore the grower should 
have a good knowledge in life cycle of the pest. 
97 
CHEMICAL CONTROL OF TEA PESTS 
4. The person who undertakes spraying should have: 
Knowledge in pesticides. 
Knowledge in the type of organisms damaging the crop. 
Knowledge in nature and degree of damage to the crop. 
Knowledge in natural enemies of the pest. 
Knowledge in the mechanism of the spray machine. 
Skill in operating the sprayer. 
Then he will not only do a good job, he will also save money by 
saving the chemical, minimizing crop loss and by better work out 
put. 
5. Effectiveness of a pesticide depends on the time of spraying. Pesticide 
should stick to the foliage for good action. Therefore, avoid spraying 
in adverse weather conditions like rain, wind and hot sun. 
Heavy rains shortly after spraying may wash off the chemical. 
Insecticides and miticides should not be sprayed when rain is expected 
within the same day. In case of herbicides and fungicides, there 
should be at least 4-6 hours free of heavy rain after spraying. If 
strong wind is blowing, spray droplets will be carried away from the 
target. Herbicides may cause serious damage to the crop due to 
spray drift. 
Spraying during the hot hours of the day with bright sun shine should 
be generally avoided due to the following reasons. 
Evaporation of volatile components of the spray. 
High risk of intoxication of the person engaged in spraying. 
Poor work out put. 
Pesticide application is best carried out in the early hours of morning 
or late afternoon or on days when the sky is overcast. 
98 
SOME USEFUL HINTS FOR EFFECTIVE SPRAYING 
6. Prior to spraying, spray equipment should be thoroughly checked 
for: 
Leakages, 
Fittings and washers, 
Smooth running of the machine (grease and oil), 
Blocked nozzles, 
Irregular flow of spray liquid, and 
Deposit pattern of the spray droplets. 
If necessary, service/repair before use. Do not wait until breakdown 
occurs. It is always cheap and easy to repair or replace parts before 
a sprayer reaches a major repair. 
7. Use clean water free of soil particles. Certain pesticides (paraquat, 
glyphosate) loose their activity when the chemical comes in contact 
with soil particles. Also soil particles cause blocked nozzles and 
damage to the machine. 
8. Make the spray solution just adequate for the day's spraying. If you 
are spraying a small area it is advisable to mix the pesticide formulation 
directly inside the sprayer tank mixing. Always use the strainer 
provided with the sprayer, when charging the sprayer. 
9. Maintain the optimum pressure levels in the sprayer tank. For spraying 
insecticides, acaricides and fungicides, 3 bar (45 psi). is optimum 
and for spraying herbicide, 0.7 - 1 bar (10-15 psi) is optimum. By 
installing a pressure gauge to the sprayer, the tank pressure can be 
noted. 
10. Wash the sprayer and clean nozzles every day on completion of the 
job. Pour clean water into the sprayer tank and operate the machine 
to remove the spray liquid remaining in the pump. This, not only 
prevents blockages the next time it is used, but also increase life 
span of the machine. 
99 
USEFUL CONVERSIONS 
Area measure: 
1 hectare = 10,000 
1 acre = 4,000 
Weight measure: 
1 kilogramme = 1000 
1 pound = 450 
Liquid measure: 
square metres 
square metres 
grams 
grams 
2.47 acres 
0.4 hectare 
2.2 pounds 
0.45 kilograms 
1 litre 
1 gallons 
1 pint 
1000 
4550 
0.57 
mililitres 
millitres 
litres 
= 0.22 gallons 
= 4.55 litres 
= 570 mililitres 
Application rate: 
1 litre per hectare 
1 gallon per acre 
0.09 gallon per acre 
11 litres per hectare 
Elevation categories of tea growing areas: 
Low country - below 600 m MSL 
Mid country - from 600 to 1200 m MSL 
Up country - above 1200 m MSL 
100 
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101 
CHEMICAL CONTROL OF TEA PESTS 
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103 
The Tea Research Institute of Sri Lanka, | f uj ( 0 2 NOV 2QQ6^\ 
Talawakelle. Sri Lanka. 
The laboratories and headquarters of the Institute are *$s^ f ^
 rt t^ 
situated at St. Coombs, Talawakelle. *1 ••. •; - _ \ ^  r xS"^ 
Address: Tea Research Institute of Sri Lanka, St. Coombs, 
Talawakelle. 
Tel: 051 2222601, 051 2223803-6 
Fax: 052 2258229, 052 2258311 
E-mail: postmast@tri.ac.lk 
The TRI Research, Advisory and Extension Center, Ratnapura. 
The Officer-in-Charge Tel: 045 2228550,2228748 
TRI Research, Advisory and Extension Centre Fax: 045 2228851-2 
St. Joachim Estate, Ratnapura E-mail: triagro@sol.lk 
The TRI Research, Advisory and Extension Center, Kandy. 
The Officer-in-Charge Tel: 081 2218832-3,081 2218509, 
TRI Research, Advisory and Extension Centre 4479480 
P.O.Box 130, Kandy Fax: 081 2218833 
E-mail: trimidcs@yahoo.com 
The TRI Advisory and Extension Center, Galle. 
The Officer-in-Charge Tel: 060 2903259 
TRI Advisory and Extension Centre Fax: 091 2237669 
Kottawa, Talgampola 
The TRI Advisory and Extension Center, Uva, Passara. 
The Officer-in-Charge Tel: 055 2288246 
TRI Advisory and Extension Centre Fax: 055 2288474 
Passara Road, Pelagahatenna E-mail: tri_uva@mail.ewist.net 
The TRI Advisory and Extension Center, Deniyaya. 
The Officer-in-Charge Tel: 041 2271496 
TRI Advisory and Extension Centre Fax: 041 2271499 
Getabaruwa Junction E-mail: trideni@sltnet.lk 
Kotapola tridenoic@sltnet.lk