Integrated Management of Tea Pests of Northeast India

Special Bulletin

www.tocklai.org CONTRIBUTORS

• Dr. Somnath Roy • Dr. Azizur Rahman • Dr. Mridul Sarma • Dr. Azariah Babu • Mr. Bhabesh Deka FOREWORD

This bulletin on Integrated Management of major tea pests of Northeast India is based on existing as well as recent findings of concluded R&D projects. The pest scenario has changed considerably in recent years and some minor pests have now become major ones. Of late, high infestation by scale insects has been reported from several districts of Assam, especially Tinsukia, Dibrugarh, Sivasagar and Golaghat, which demands immediate attention.

This bulletin contains brief descriptions of some major pests of tea, their biology and the remedial measures needed to form an integrated pest management strategy.

I hope the bulletin proves to be beneficial to the industry.

A.K. Barooah Director 21st September 2018 CONTENTS

Topics Page

introduction 1

THE TEA MOSQUITO BUG 1

THE RED SPIDER MITE 6

LOOPER COMPLEX 10

Red Slug Caterpillars 21

Tea thrips and jassids 24

SCALE INSECTS 28

TERMITES 30

TEA WHITEFLY 33

Preparation of Plant based biopesticides 34 at the garden level Integrated Management of Tea Pests

INTRODUCTION

Tea, Camellia sinensis (L.) O. Kuntze, is a perennial crop that is grown as a monoculture on large contiguous areas in India. Being a plantation crop, tea provides a relatively stable micro-climate and food supply for several notorious pests such as insects, mites, nematodes etc., which cause substantial loss of foliage. However, region-wide variation in pest diversity exists due to the influence of climate, altitude and the age of the plantation etc. This publication provides details on tea pests and their possible management strategies. In the case of complex pest situations, total avoidance of pesticides in tea is not possible; although due to the sensitive nature of the crop, pesticide use must be minimal. A tentative IPM strategy for tea cultivation in Northeast India has been proposed in this bulletin, which may ensure low–cost, eco-compatible pest management packages with minimal residue problems. Monitoring pests: Monitoring the pest is one of the cornerstones in integrated pest management. The first and probably the most important step is to divide larger areas of tea plantations into small manageable sizes (blocks), using natural boundaries such as roads, footpaths, main drains etc. to enable convenient supervision.

Components of a Micro-monitoring system: • Micronizing -dividing a big division/section into blocks small manageable size (blocks) using of natural boundaries such as roads, footpaths, main drains etc. • Individual Responsibility • Accountability • Spotting/Flagging • Spraying • Post spraying survey and Re-flagging • Repeat round of spraying with different chemicals • Rehabilitatory spray

The Tea Mosquito Bug (TMB)

The Tea Mosquito Bug is considered to be one of the most serious pests of tea in almost all tea-growing countries, as it only attacks the young shoots that make up the actual crop of tea. In recent years, the long and unusual weather patterns during the peak season of activity of the TMB makes it even more difficult to control this pest.

Biology of the TMB:

Egg: The egg is elongated, sac like, white and about 0.8-1.0 mm in length. The position of the egg is marked by of two hairs of unequal lengths projecting from the surface. Nymph: The freshly hatched nymph of Helopeltis is dirty yellow in colour. The colour of the first and second instar nymph is greenish yellow, but it becomes green in the latter instars. Nymphs are wingless. Adult: The adult is a tiny insect with long antennae and wings. The thorax is yellow in the female and black in the male. The adult is not a strong flier, the normal range of flight being from bush to bush, between alternate bushes at a time.

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Egg 1st Instar Nymph 2nd Instar Nymph

3rd Instar Nymph 4th Instar Nymph 5th Instar Nymph

Adult (Male) Adult (Female)

Life Stages of the Tea Mosquito Bug

Nature of Damage:

The nymphs and adults of TMB suck the sap of the young leaves, buds and tender stems and while doing so, they inject toxic saliva which causes breakdown of tissues around the site of feeding. Within 2-3 hours of sucking, a circular spot is formed around the feeding point and in 24 hours it becomes translucent and light brown in colour. Within a few days, the marks appear as dark brown sunken spots which subsequently dry up. The badly affected leaves become deformed and even curl-up. In addition, due to oviposition, the tender stems develop cracks and over-callusing, which lead to blockage of the vascular bundle, thereby affecting the physiology, causing stunted growth and sometimes die-back of the stems.

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Damage symptoms of TMB

Seasonal Incidence:

Adults and nymphs of Helopeltis could be seen on tea bushes almost throughout the year, but peak in the incidence in Northeast India is noticed during June and July, often extending up to September, when the number of rainy days is high. In sub-Himalayan Dooars tea plantations, the population of H. theivora is abundant throughout the year. However, the lowest population of this pest is noticed during the winter months of December to February. The population usually begins to build up in the months of May/June, reaching a peak during September to November.

Duration of life stages of TMB in the climatic conditions of Assam and Dooars

Life stages Duration in days Nov.-Jan. Mar-April June-July Aug.-Sept. Assam conditions Incubation period 16-20 7-8 4-6 5-6 Nymphal period 19-20 16-20 9-14 8-10 Total duration (Egg to adult) 35-40 23-28 13-20 13-16 Dooars conditions Incubation period 6-18 7-15 6-8 4-8 Nymphal period 9-20 8-13 8-10 8-10 Total duration (egg to adult) 15-32 16-24 14-17 13-16

Monitoring: Initially, the sites of initial pest build-up should be detected and marked by observing feeding punctures of the Helopeltis. Upon detection of Helopeltis attack, the spotter should put flags on the affected bush. There should be a single-colored flag in the centre and four different colored flags in square formation around the affected bushes (5 rows from surrounding). Hard plucking should then be carried out to remove all the affected shoots, followed by spraying in the flagged area with the recommended insecticide. Spraying should commence from the outside, towards the central flag.

Sampling Method: The percentage of infestation has to be assessed by collecting 100 shoots from the plucker’s basket and counting the number of infested and non-infested shoots to work out the percent infestation.

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IPM techniques for tea mosquito bug:

Keep all the drains functional to avoid water logging during the monsoon. Localised depressions should be prevented. • Keep the tea fields free from weeds. • In severe infestation, level off skiff (LOS) operations should be followed to minimize the infestation by the next generation of TMB • The TMB prefers moist conditions and moderate temperatures. For that reason, populations of this pest are often higher under heavy shade. Regulate the shade in densely shaded areas by lopping the lower branches of shade trees. Moderate shade of 60% is preferable. • The side branches of tea bushes should be removed to improve ventilation and effective spraying in closely planted fields. • A closer plucking schedule helps remove the inserted eggs and the early nymphs of TMB, before they cause more damage. • The ecotone (border) between forest line and tea plantation needs to be kept clear of weeds and noneconomic plants. Bamboos near tea areas – should not make over shaded. • Uncut drain sides – ideal protected area for TMB. Therefore, side branches of the tea bushes near drain sides should be cut and attention should be taken during spraying for proper coverage. • During cold weather, pruning and skiffing should be resumed from the periphery towards the centre and around 50-60 bushes should be kept untouched for a day or two in the centre to serve as a trap for adult TMB. After thorough spraying of the recommended pesticides, these bushes should be pruned or skiffed. • During cold weather proper bush sanitation like removal of parasitic plants on tea bushes, cut all twiggy thin, diseased tea branches etc. • Alkaline wash or lime wash should be done. • If the weather is rain-free, apply a round of systemic insecticide like thiamethoxam 25WG @ 1:4000(HV)/ thiacloprid 21.7% SC @ 1:1000 (HV)/clothianidin 50 WDG@1:4500 (HV). During rainy spell, spray a round of synthetic pyrethroid, like deltamethrin 2.8EC @ 1:2000HV/ bifenthrin 8 SC @ 1:1600. • Avoid repeated application of the same chemical. • Recent studies have suggested that in certain pockets of upper Assam area thiamethoxam /thiacloprid and clothianidin at TRA-recommended dilution did not provide the desired level of control against TMB. In these areas, thiamethoxam + deltamethrin/ Bifenthrin + sticker, at their recommended doses, showed better results if proper TRA-recommended cultural practices are also followed. • Applying crude aqueous extracts of native plants viz. Clerodendrum viscosum (leaves and succulent stem), Polygonum hydropiper (leaves and succulent stem),Cassia alata (leaves and succulent stem), Xanthium strumarium (leaves and succulent stem), Vitex negundo (leaves and succulent stem) and Amphineuron sp.(leaves and succulent stem) @ 5-8% concentration may also be done in case of lowand moderate infestation of the pest. • Mixing the crude pant aqueous extracts @5% (mentioned above) with conventional pesticides at recommended dilution may help extend the spraying intervals (long term control) (New Experimental findings) • Mix 0.5% sesame oil formulation with PPC cleared insecticides recommended for TMB to enhance the efficacy of that insecticide (New Experimental findings). • Spraying of the entomopathogen, Beauveria bassiana (Bals.- Criv.) Vuill, at 2 kg/ ha minimized infestation of the TMB compared with the control under Dooars and Darjeeling field conditions. • Spray 2% potassium chloride (KCl) or mined potassium sulphate (K2SO4) straight or in combination with insecticides and this will impart physiological resistance to plants

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against sucking pests. • The Barrier method of spraying should be followed. • Spraying should be undertaken in early morning and late afternoon hours with proper spraying machine and recommended nozzle. • Application of conventional rehabilitatory spray (Boric acid 0.1% + ZnSO4 1% + Urea 1%) or Bacillus subtilis formulation (TRA stain)@5% will give effective recovery in severely TBM infested area. These treatments should be done only after recovery of the pest. • Encourage the population of natural enemies by legitimate use of pesticide and by giving emphasis on non-chemical methods of pest control.

Method of barrier spraying for TMB

Lacewing (Adult) Lacewing (Larva) Lynx Spider

Web making spider Sycanus sp Praying Mantis

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The Red Spider Mite

The Red Spider Mite (RSM), Oligonychus coffeae Nietner (Acari: Tetranychidae), is a major pest of tea in most tea-plantations of different countries. At the time of feeding, the larva, nymphs and adults of RSM lacerate plant cells, producing minute characteristic reddish brown marks on the upper surface of mature leaves, which turn red in severe cases of infestation, inhibiting photosynthesis of the plant, which leads to defoliation and crop loss. The pest persists on tea all year round, with a variation in population numbers depending on the season. Their number increases as the weather becomes dry and warms up with a decrease markedly, once the rains set in. Under optimal conditions, there may be 22 overlapping generations in a year. Parthenogenesis is known to occur in RSM, which play a major role in population buildup; consequently, all mite stages can be found at a given time. Their infestation is mainly confined to the upper surface of the mature leaves and could readily be identified by the bronzing of the leaf.

Damage symptoms:

• Reddish brown spot develop at the point of feeding • Brown patches are formed as a result of repeated sucking • In severe cases leaves dry up and fall off

Damage symptoms of the tea red spider mite

Spread of the RSM population on tea bushes mainly takes place through the adult females, but even the nymphs disperse from heavily infested leaves. The bushes touch each other, and it is natural to expect the mites to migrate from bush to bush, by crawling from leaf to leaf and sometimes by crawling over the intra bush ground. On a badly infested bush, the top is often found to be heavily webbed, threads extending from leaf to leaf and to adjacent bushes, and the mites are found crossing in large numbers to other bushes. Dispersion is also effected by wind, which carries the mites for considerable distances. The fact that infested bushes are scattered in the fields, suggests that the mites on fallen leaves are probably carried by the wind. The mites are occasionally found suspended on long threads, and in this way they can be carried by the wind. Labourers working in tea plantations are also responsible for spreading the mites by carrying them on their clothes and baskets. Cattle, goats, birds and insects too play an important role in dispersion, carrying the mites on their bodies. Incidence of mites has also been found to be related to accumulation of dust on tea leaves due to vehicular movements or other operations in the plantations. The dense web produced by spider mites is a complex structure of silken threads comprising

6 Integrated Management of Tea Pests protein. The web has been hypothesized to serve various purposes, such as attachment to the leaf and protection against adverse weather conditions, in modifying their microhabitat to hinder predation and protect their eggs The red spider mites breed throughout the year, peak being during the months of March- May and September- October.

Life History:

Life stages Duration (Days)

Egg: The egg is ovoid or spherical, smooth, with a slight 3.5 - 4.5 (during depression on the exposed top side and flattened on the summer) lower surface (Das 1959a; Rao 1974a). A short hair-like 10.5-11.5 (during winter) process arises from the upper pole and bends in the form of a hook. The eggs are blood red to chrome red glossy and shining, but change to light orange before hatching. Eggs are laid singly on the upper surface of the leaf along the mid-rib and veins. Larva: The larva is almost round and it has six legs. A freshly 1.0 (during summer) hatched larva is yellow orange but the color subsequently 1.8 (during winter) changes to pale orange. Nymph: The protonymph carries four pairs of legs. The body 3.9 (during summer) is oval, the anterior legs are pale crimson, whereas the 6.9 (during winter) posterior pairs are deep reddish brown. Deutonymphs are like protonymphs, but larger. Adult: The minute adult mites are just visible to the naked eye. Their body color differs from orange-red to dark red, with black patches. The male differs from the female in size and also in shape of the body. The female is nearly elliptical or oval, the abdomen being broadly rounded at its posterior end. Total life cycle 8.4-9.4 (during summer) 19.2-20.2(during winter)

Life Cycle Stages of Tea Red Spider Mite

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Sampling Procedure: According to Kakoty (1994), the sampling procedure involved picking 100 bushes at random from a section of a tea plantation. It should first be examined for the presence of the mite. Ten leaves should be collected at random from each bush, both from the top and the middle zones (5 leaves from Sampling Procedure the bottom and 5 leaves from the middle) and examined with a 10 x magnifying glass for RSM. Spot or blanket application of an acaricide will depend on whether an infestation in the field is random or uniform. If 15 20% bushes show RSM infestation in certain areas, spot application with a suitable acaricide should be adequate. But if the infestation is above 20% and the mite is uniformly distributed in the area, blanket application is required. IPM techniques for the Red Spider Mite

• Un-shaded condition is favourable for RSM: ensure the recommended stand of shade. • Protect the roadside bushes from dust by growing hedge plants like Phlogacanthus thrysiflorus (titaphool) or applying water on such dusty roads at regular intervals • Restrict cattle trespass and the pluckers from entering the un-infested areas from infested field. Arrange plucking first in uninfested section to stop dispersal of red spider mite to healthy section • Removal of alternate hosts (Borreria hispida, Scoparia dulcis, Melochia corchorifolia and Fussiala suffruticosa) • The bushes in ill drained or waterlogged are more prone to RSM: Maintain proper drainage. • Tea bushes suffering from water logged condition are weak and more liable tored spider mite infestation. So, proper improvement of drainage should be done to get rid of the problem. • ‘Matidals’ facilitate the movement of RSM from alternate hosts to tea bushes so removal of ‘matidals’ is must to minimize its attack. Improvement of bush hygiene by knife cleaning, lime washing in the pruned sections during cold weather will reduce red spider mite infestation. • Potash and phosphorus application decreased the intensity of RSM infestation in tea. Avoid application of only nitrogenous fertilizer, instead apply recommended dose of NPK. • Red spider mite affected fields should get a new tier of maintenance foliage since the infested bushes are very weak due to defoliation of maintenance leaves. • While spraying, coverage of both surfaces of foliage is necessary. During high cropping seasons control measures should be undertaken as spot treatment only. • Spot spraying and safer pesticides should be applied to encourage natural enemies populations like lady bird beetle, green lace wing, predatory mites, etc. • Some indigenous plant species viz. Clerodendrum infortunatum (Bhant), Cyclosorus opulentum (Fern), Cassia alata (Dadmurdan), Pongamia pinnata (Karanj), Azadirachta indica (neem), Adhatoda vasica (Adosa), Phlogocanthus thrysiflorus (Lal basak), Xanthium strumarium (Banokra), Acorus calamus (Vacha), Polygonum hydropiper (Machoti), Annona squamosa (Ata), Tithonia diversiflora (wild sun flower), Urtica dioica (sisnu) were found to be effective against red spider mite. Application of 2-3 rounds 5% aqueous extract of above mentioned botanicals alone or in mixture at 7days interval

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should be done in mild or moderately red spider mite infested tea sections for effective control. • Application of two rounds of 1% Sesame oil formulation (SOF)/Karanj oil formulation (KOF) at 7days interval may give effective control of red spider mite under field condition (new experimental findings). • Application of two rounds of 1% paraffinic oil at 7days interval for effective control of red spider mite in mild to moderately infested tea sections. • Two round application neem karnel aqueous extract (NKAE)[neem karnel powder + organic synergist @ 1:1] at 7days interval showed promising result to minimize red spider population in field level (new experimental findings) • Application of two rounds of TRA microbial products like Metarhizium anisoplae+Beauveria bassiana spore suspension (1:1) @5% and Paceilomyces fumosoroceus 2kg/ha+ jaggery 2kg/ha at 7days interval showed promising control of red spider mite in mild to moderately infested tea fields (new experimental findings). • Application of lime sulphur @ 1:40 dilutions during cold weather drastically reduced the carryover of red spider mite to the next season. • Apply a round of Fenpyroximate 5EC/SC (1:1500/1:2000)/Ethion* 50EC (1:400)/ Dicofol* 18.5EC (1:400)/ Propargite 57EC (1:400)/Sulphur** 80WP (1:200) dilution followed by another round with Hexythiazox 5.45 EC (1:2500)/ Spiromesifen 22.9 (1:1000) dilution with HV sprayer after 14days of first application. • In severe attack of red spider mite one round of Fenazaquin 10 EC (1:400)/ Etoxazole 10 SC (1:1600) dilution with HV sprayer will take care of the pest. • There are several naturally occurring insect predators for red spider mite, such as coccinellid and staphylinid larvae, lacewing larvae, and mite predators, most importantly species of the families Phytoseiidae and Stigmaeidae. NB. • * Avoid repeated use of these molecules for the time being, as their susceptibility against the RSM has reduced. • ** It should not be sprayed when temperature exceeds 270 C

Natural enemies of the Red Spider Mite

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Looper Complex

In recent times, besides the common looper (Buzura suppressaria), other species of looper caterpillars viz., Hyposidra talaca¸ Hyposidra infixaria, Ectropissp., Ascotis sp., and Cleora sp. are also found to occur in tea plantations of Assam and North Bengal. The outbreak of these loopers is considered to be a culminating effect of various factors like climatic changes, deforestation, large scale use of inorganic insecticides earlier, against other pests of tea etc. As these insect pests have a number of advantages like very short life cycle with about 8 generations in a year, fast multiplication, no hibernation during the winter months and lack of effective natural enemies at present etc. H. talaca also known as ‘black inch worm’ is found to be the most predominant species among the looper complex infesting tea.

Old looper pest of tea Buzura suppressaria

Emerging looper Hyposidra talaca

Emerging looper Hyposidra infixaria

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Emerging looper Ascotis sp.

Emerging looper Ectropis sp.

Nature of damage:

The damage symptoms of different species are more or less similar. The newly hatched caterpillars make small holes along the margins of young leaves and then eat from the margins. Young ones are very often seen on growing shoots and buds scrapping on the leaf surface. The fully grown caterpillars prefer semi mature to mature leaves. From late third instars, they become voracious feeders. In severe conditions, bushes are completely stripped of foliage. Even the bark of small branches is eaten away in the absence of foliage. Old looper, Biston (=Buzura) suppressaria (Lepidoptera: Geometridae)

This is the earliest known species of looper caterpillar infesting tea. The moth is grayish white, finely speckled with black. The males are generally smaller than the females and are easily distinguished by the bipectinate (feathered) antennae. The female moth lays eggs in heaps, each containing 200-600 eggs covered with a buff coloured hairs. The most common site for the deposition of eggs is the trunk of shade trees or any other tall trees in the vicinity of tea fields. The young caterpillar is dark brown with greenish white lines along the back and side. The body colour soon turns to light green and with age, it acquires a brownish grey colour similar to that of a mature twig of tea. There are five larval instars. The full grown caterpillar moves down to ground for pupation at a depth of 2.5-5 cm in the soil under tea bushes. The duration of pupal stage is about three weeks in summer and more than three months during cold weather. The life cycle is completed in about 72 days during March-May and in about 60 days in June-July.

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Duration of different stages of B. suppresaria

Duration in days Stages March-May June July Egg 14.5 13.0 Caterpillar 38.5 29.0 Pupa 19.0 18.0 Total duration (Egg to adult) 72.0 60.0 Black looper, Hyposidra spp. Two species of black looper viz., H. talaca and H. infixaria are now predominant in tea plantations of Assam and North Bengal. They also knew as ‘black inch worm’. The caterpillars of H. talaca and H. infixaria are polyphagous in nature and reported to feed on a number of forest plants and weeds from India.

Hyposidra talaca (Lepidoptera: Geometridae) Early instars caterpillars are brown to black in colour with transverse six white bands on the dorsal side of the body. In mature larva, the bands disappear and its colour changes to brownish grey with white spots on the body. The caterpillar passes through 5-6 larval instars.

Hyposidra infixaria (Lepidoptera: Geometridae): Early instar caterpillars are brown to black in colour with transverse six white bands on the dorsal side of the body. The colour of mature larva is brownish grey with two transverse lines at the thoracic region of the body. The adults are pale or greyish in colour. The distinguishing characteristic of this species is that the male moths bear a tuft of hairs at the abdominal tip.

Ectropis sp. (Lepidoptera: Geometridae): The early instar caterpillars are brownish in colour with black stripes on the dorsal side of the body. The full grown caterpillar is about 30-35 mm in length and look like a dried up twig of the tea bush. The adults are pale yellow in colour with black wavy lines. The males are smaller than the female with bipectinate antennae.

Ascotis sp. (Lepidoptera: Geometridae): The early instar caterpillar is light green in colour. A matured caterpillar changes its colour to greenish grey with a pair of tubercle located dorsally on the abdominal region of the body. The adults are greyish in colour with brown spots on each wing.

Cleora sp. (Lepidoptera: Geometridae): The wing base of moth is white with creamy to black or even greyish black. Unlike Ascotis sp, the forewings are somewhat rounded. Fully grown caterpillars are robust with orange head and thoracic legs. There is a pair of reddish brown tubercles dorsally and a smaller pair dorso-laterally in anterior abdominal segment of full grown caterpillar with a narrow transverse greyish bar anterior to them.

Special notes on Hyposidra talaca: most common looper

Oviposition behaviour

The moths of H. talaca prefer to lay their eggs under the scales, cracks and crevices of barks of trees such as Albizia odoratissima, Albizzia lebbek, Acacia lenticularis, Acacia auriculiformis, Derris robusta, Lagestremia speciosa, Schima wallichi, Dalbergia sisso and D. assamica about 0.02 to 7.2 m above the ground. Eggs are also laid under the lichen

12 Integrated Management of Tea Pests cover and root mantles of epiphytes hemiphytes, any rough surface like dry tea leaves. The shade tree A. lenticularis was found to host the highest number of egg clutches of H. talaca while Melia azedarach, which has comparatively a smoother bark and is lesser colonized by epiphytes and hemiphytes, was not often chosen as oviposition site. Moreover, oviposition on the scaly bark of lower-middle portion of a shade tree possibly facilitates easy spread of early instars of the species through wind to the under-growing lush green tea bushes and also reduce the risk of bird predation. Eggs are laid in clusters through 5–6 days, each egg mass contains 200–500 eggs with an average of 258 eggs per cluster.

Egg laying under the scales, cracks and crevices of barks of shade trees and dry tea leaf surface

Life history

Studies on the biology of H. talaca have been extensively carried out by TRA. Six to eight generations in a year, without obligatory winter diapause, were reported from NE India on tea. On an average, the life cycle took 55 days during the winter months of December– February (mean maximum temperature 25°C and mean minimum temperature 12°C) and 30 days during the warmer months of April–June (mean maximum temperature 31°C and mean minimum temperature 23.5°C). The eggs are oval, initially greenish blue, turn yellow and finally orange as they develop. The incubation period is about 6 days. H. talaca usually has five larval instars and an occasional 6th instar. The first three in¬stars are black with seven transverse white stripes. The 4th instar caterpillars are black to dark brown with seven stripes. The 5th instar is dark to light brown, with minute black spots dorsally. Larval stages are with three pairs of thoracic legs, one pair of abdominal prolegs at the rear and one pair of claspers. The pupa is blackish brown, with characteristic anal process . Pupation takes place in the soil around the collar region of tea bushes and shade trees or in the cracks and crevices of the bush frame. The adults exhibit sexual dimorphism. Females are with grayish to blackish brown wings having wavy dark semi-circular patches and distinct sub-marginal notch in the forewings (Das et al. 2010a; Anonymous 2011). Males without distinct sub-marginal notch in the forewings. Females are about 3 times heavier and their wings are 1.5 times wider than those in males.

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Eggs 1st instar larva 2nd instar larva

3rd instar larva 4th instar larva 5th instar larva

Male Female

Pupae Adult Moth

Life stages of Hyposidra talaca

Dispersal

The moths emerging from pupae appear to be capable of dispersing widely, but the maximum extent of their flight is not yet known. After mating the females prefer the bark of shade trees to lay eggs in clutches. The neonate larvae on shade trees drop down using salivary thread to access the tea bushes underneath and as well get dispersed through wind to a larger area. In the case of severe infestation, the silken salivary threads of neonates appear as spider net. Some neonates move upwards and reach the foliage of the shade trees and complete their development of early stages and then disperse in large numbers from the shade trees by hanging and swinging with the help of salivary threads.

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A B C

Dispersal of larvae of H. talaca. A, dispersal of neonate larvae from shade trees using silken salivary thread. B, silken salivary threads of neonates appearing as spider net in tea bushes, C. silken salivary threads of neonates appearing as spider net in tea bushes.

IPM techniques for looper caterpillar

• Hyposidra talaca remains active through the season and it is the highest during winter months. Maximum eggs are laid during November-April and there is a peak of infestation of the caterpillars in February-March. Initial brood is already visible in some gardens. To destroy the eggs, laid in cracks of the splitting bark of shade tree collars, heat treatment with burning torch (Mashal) should be applied around shade tree trunk up to 6-7 m followed by lime washing. Scrapping and cleaning of shade tree trunk may be adopted to avoid egg laying by moths and also to expose the eggs laid during January.

Cultural practices for looper control (Scrapping, mashal burning and lime wash) of shade tree trunk

• Light trapping of moths should be done for around 3 hours during dusk. Few monitoring lights should be placed in prone sections and if number of moth attracted to these lights is increasing light trap should be increased to at least one in 10 ha area. The height of light trap installation should be approximately 6 ft, otherwise only male moths will be attracted. Light trap acts as monitoring tool and predict the brood occurrence.

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Light trap collection of looper moth

TRA-developed multipurpose traps

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• Hand collection of looper as well as chrysalids from the collar region should be done if infestation is confined to a limited area. • Chyrsalid collection by Forking the soil around collars of tea bushes in sections where there was more Looper attack • Pupae are generally found within 15-20 cm of the tea bush collar region at a depth of 2-5 cm. Also found on the frame and cracks of old teas bushes and under the pruning litter of LP/DS sections. • Large numbers can be found on the edges of deep drains inside the tea area and these spots are difficult to spray. • Pupae should also be collected from the areas adjacent to the tea section

Pupation in tea bushes and soil

• Pruned and deep skiffed bushes should be checked critically, if any active Looper caterpillar is noticed a round of recommended insecticide (preferably quinalphos 25EC @1:400 with sticker) should be applied even on naked frames. If it is overlooked looper will continue to feed on growing buds and bushes will fail to recover resulting in death of bushes in large patches, which is generally confused with drought damage. This operation also helps in reduction of scale insect infestation.(new experimental finding). • Creation of ovipositional barrier against looper moths: Yellow polythene sheets (commercially available; 1.5 ft breadth) can be wrapped around the shade trees in two bands. One band should be just above the plucking table of tea and the second one at a height of 12 ft. of the shade trees. These yellow sheets can be than coated with Hot Melt Pressure Sensitive Adhesive (HMPSA) as a sticky material. The middle portion of the trees is kept unwrapped, where the looper moths can lay eggs. On hatching, the early instar caterpillars when moving, either upwards or downwards, will get stuck either in the lower band or the upper band of sticky yellow sheets. It has been observed that normally gravid looper moth can fly up to 10-12 ft height, after that they crawl

17 Integrated Management of Tea Pests upward, during which time they also get stuck up in the sticky sheet. Additionally, the lower portion of yellow sheet attracts thrips, green hoppers, whiteflies, and winged termites which get stuck in the sticky coat. This intervention drastically reduces looper droppings from the shade trees. (new experimental findings)

Use of sticky yellow polethene as IPM tools for tea looper

Lower Band Upper Band

Use of sticky yellow polethene as IPM tools for tea looper

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• 1st instar looper can be controlled by spraying quinalphos 25EC or 20AF (1:400 HV). For controlling late instar loopers apply recommended emamectin benzoate 5% SG @ 1:2500 (HV) [i.e. 80 g in 200 l water] or flubendiamide 20 % WG @ 1:5000 (HV) [i.e. 40g in 200l water). • In rainy period used Deltamethrin 2.8 EC @ 1:2000 mixed with urea (2%) and sticker may be effective. • In cold weather, use of flubendiamide is quite effective due to its long persistency as compare to other recommended Hand collection of caterpillar insecticides. • Normally, emamectin benzoate is recommended during plucking season due to its shorter pre-harvest interval. After chemical treatment, surviving late instar caterpillars should be hand collected. • Garden workers should be educated and motivated to collect loopers. Manually collect residual looper population after insecticide application, wherever possible. Collected looper Chyrsalids

Biological control: The records of native natural enemies of eggs, caterpillars and adults of H. talaca are very few. An ant, Tetraponera rufonigra (Jerdon) (Hymenoptera: For¬micidae), Oxyopes sp, Shield bug are reported to attack H. talaca. Two parasitoids, Cotesia sp. (Hymenoptera: Braconidae) and Argyrophylax sp. (Diptera: Tachynidae) also parasitize the caterpillars of H. talaca. Mermithid nematode worm also recorded as natural enemies of H. talaca.

Natural enemies of the tea looper

19 Integrated Management of Tea Pests

• TRA-developed nuclear polyhedrosis virus (NPV) formulation shows very promising results in the management of tea looper at the field level (not encouraged to use in Assam conditions due to muga silk cultivation) (new experimental findings). • Commercial formulations of Bacillus thuringiensis var. kurstaki (Btk) (17,600 IU/ mg: 3.5%) @ 750 mL/ha suppressed 50-67% of looper population in the field. (not encouraged to use in Assam conditions due to muga silk cultivation). • Field trials with alkaline aqueous extracts of Polygonum hydropiper, Annona squamosa, Clerodendrum viscosum, Argyreia speciosa and Leucas aspera have revealed that these can act as source of promising biopesticide to minimize the early instar or initial stage of infestation.

Cadaver (virus-infected) of Hyposidra talaca (A); occlusion body of NPV isolated from H. talaca (A1); electron microscopic view of HytaNPV (A2) Bacteria-infected Hyposidra talaca (B); Bacillus sp. HT01 isolated from cadaver of H. talaca (B1)

20 Integrated Management of Tea Pests

Red Slug Caterpillars Eterusia Aedea (Lepidoptera: Zygaenidae):

The red slug caterpillar of the colourful moth, Eterusia aedea (Linnaeus, 1763) (Lepidoptera: Zygaenidae) has earned considerable importance as a defoliator of tea during the last decade in major tea-producing countries like China, India, Sri Lanka, Japan and Taiwan. The damage is caused by all stages of larvae which feed mainly on mature tea leaves. In severe infestations bushes can become completely defoliated and sometimes the bark is also damaged. The pest is found sporadically throughout the plucking season or the flush period and even in winter. Under optimal conditions, there may be 3–4 generations in a year.

Life Cycle: Egg. Eterusia aedea lays eggs in masses on the blade and axils of leaves which are covered with buff colored scales and hairs, preferably during night. Freshly laid yellow colored-eggs turn green before hatching. Eggs are oval in shape, Incubation period varies from 8 to 12 days in May–June, however in winter, the incubation period is prolonged.

Larva. Larval period consists of five instars. Caterpillars are brick red to brown in colour, having three rows of tubercles on each dorsal half of the body. The tubercles bear hairs, a dark brown head and pores. It has three pairs of thoracic legs and five pairs of prolegs the last one being the largest acting as clasper. Each pair of legs is equipped with a disc like structure at its end for attachment to the plant surface. The first and second instar larvae mainly nibble the epidermal surface of the leaf, while from the third instar, they start feeding from the side of the leaf blade. A brown coloured ring appears on the dorsal surface of the body of the third instar which continues in the fourth and fifth instars. The last two instars can consume entire leaf blade and soft stem part of tea as well. The larvae when disturbed exude nontoxic thick clear fluid from its pores located on their back. During day time, they feed in shady places, and may remain on back side of the leaf or may descend to the ground and remain concealed under dried leaves and clods of earth or any convenient shelter. They are also seen climbing up the shade trees during forenoon. Caterpillars disperse when their host plants get depleted and denuded of foliage. In severe infestation, an extensive migration of the caterpillars from the affected areas can be observed. They can be seen crossing the roads between the sections (Anonymous 1994). Pupa. Pupation takes place usually within the folded leaves. Pupae are pale yellow with a pinkish yellow cocoon.

Adults. The moths are brilliantly colored. The males are slightly smaller than females in body length. A unipectinate antenna is found in males whereas in females these are long filiform with feathery tip. Male and female moths have a life-span of 5–6 days and 6–7 days, respectively. The total life cycle is approximately 50–63 days.

IPM techniques for red slug caterpillar:

• Field and plant sanitation: Removal of weeds (reservoirs of pests), adequate shade, suitable fertilisers, improvement of drainage system, cold weather practices, ground sanitation etc. encourage the growth and vigour of the plants increasing their ability to resist attack by insects. During winter, trunks of most of the shade trees were scrapped and followed by white washing with lime and synthetic pyrethroid mixture (Anonymous 2014), which act as oviposition barrier for moths. As red slug caterpillars normally rest under the bushes during hot day time, a ring of crude petroleum jelly or grease on and around the bushes would prevent the caterpillar to get on a plant by evening and go to other bushes

21 • Mechanical control: Some of the measures like hand picking, catching in nets and bags, trapping with lights or sticky bands, laying down of an impassable barrier to confine the pest within bounds are quite effective. Hand collections of caterpillars during minor attacks or leftover caterpillars after pesticide treatment are occasionally performed in some gardens. The success of this method depends on its urgent implementation after pest occurrence is spotted.

2 1

3 4

5 6

1 Eggs of E. Aedea; 2. Nibbling of the epidermal surface of the leaf by early instars of Red slug, an indirect sign to ascertain the red slug infestation; 3. Fully grown Red Slug caterpillar; 4. Larva exuding nontoxic thick clear fluid from its pores located on their back; 5. Pupa of E. Aedea 6. Adults of E. Aedea

22 Integrated Management of Tea Pests

• Barrier: A band of used Engine oil on the ground will act as a barrier and will halt or destroy a migrating swarm of red slug caterpillar. • Physical Control: Smoke produced by the burning of locally available weeds along with dhuna (amorphous substance chiefly producing carbon disulphide) and fresh Ageratum conyzoides can repel the moths of red slug and looper. • Light traps: Light traps are an important component of physical control and play a great role in red-slug caterpillar management in tea. In tea fields, black-light traps, the Pest-O-Flash traps, Actinic BL light trap were found useful for capturing the moths. Light traps when kept at a height of 0.5m above the plucking table, facilitate appreciable catch of adult moths. However, the drawback of such light traps is that only male moths of red slug are normally attracted as the gravid females are sluggish in their movement and seldom get into trap. • Sticky traps: Polythene sheets (commercially available; 1.5ft breadth), when wrapped around the shade trees in a band just above the plucking table of tea and coated with a sticky material Hot Melt Pressure Sensitive Adhesive (HMPSA), was found effective in trapping and controlling red slug moths as well as acting as barrier for caterpillars. • Chemical Management: Among approved list of pesticides, quinalphos 25EC @ 1:400 (HV) was found to be most effective against red slug caterpillars. Emamectin benzoate5% SG @ 1:2500 (HV) and flubendiamide 20 % WG @ 1:5000 (HV); were also giving better control. Synergistic action of Paraffinic oil formulations (1%) and urea (2%), enhanced the toxicity of synthetic insecticides against red slug. Therefore, the recent recommendation for controlling redslug caterpillars counts much on using i)combination of deltamethrin 2.8 EC@ 1: 2000 and Servo Agrospray T. Oil @ 1%, (90-92% mortality); (ii)combination of Deltamethrin 2.8 EC@ 1: 2000 and Urea@ 2% (80-90% mortality)(iii) combination of Fenpropathrin 30 EC @ 1: 1600 and Servo Agrospray T. Oil @ 1% (92-98% mortality) and (iv) Fenpropathrin 30 EC @ 1: 1600 and sticker (80-93% mortality)(new experimental findings). • NKAE @ 6% and @8% showed considerable mortality against early instars of red slug. • Commercial formulations of Bacillus thuringiensis var. kurstaki (Btk) (17,600 IU/mg: 3.5%) @ 750 mL/ha suppressed 50-70% of red slug catterpillar population in the field. (not encouraged to use in Assam conditions due to muga silk cultivation) • Thorough drenching of top, middle and bottom hamper of bushes with spray fluid is necessary to kill the residual population.

1 2 3 4

5 6 7

Light traps (1-4) used to collect red slug moths, white washing of the bark (5) of the tree as oviposition barrier and yellow sticky traps (6) for trapping moths, smoke treatment as repellent (7)

23 Integrated Management of Tea Pests

Tea thrips and jassids

Tea thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae): The Tea thrip is a polyphagous and cosmopolitan pest. Its infestation on the tea plant, has increased considerably over the past few decades as a result it is now established as one of the major sucking pests in the tea growing areas of India in general and NE India in particular. A number of factors such as climate change, deforestation, over-reliance on pesticides, coupled with the capability of thrips to sustain and survive in monoculture cropping areas, appreciable reproductive rate both by parthenogenesis and sexual mode, short generation time, ability to survive as cryptic, quiescent pre-pupa and pupa and development of resistance to insecticides etc., result in periodical outbreaks. Tea thrips cause both direct and indirect damage to tea plants by feeding as well as egg laying on tender leaves and bud that causes stunted plant growth and significant yield loss.

Life cycle: Egg: The egg is bean-shaped, slightly narrower at one end and is almost colourless when freshly laid. Nymph: The newly hatched nymph is almost white but soon after sucking of plant sap, the colour gradually changes to pale yellow. The second instar nymph is orange yellow. Pre-pupa: The pre-pupa can be recognized by the free antennae directed forward while in the pupa; the antennae are reflected over the head to reach the middle of the pro-thorax. Adult: The adult insect is pale yellow in colour, the abdomen being paler. The female measures 1.05 mm long and 0.19 mm width. The male measures 0.71 mm in length and 0.14 mm in width.

Nature of damage: Both adults and nymphs generally live and feed inside the leaf folds of unopened or partly opened tea buds as well as on tender leaves. Feeding by piercing and sucking with the help of functional left mandible (right side vestigial) causes damage to the host foliage while extracting the contents from the individual epidermal cells (meristem tissues), leading to tissue necrosis. The puncture marks appear as minute brown spots in scattered patches and/or in continuous lines. The slits made in continuous lines of the bud later form corky lines often called ‘sand papery’ lines and there may be two or four such lines on a leaf, one or two on each side of the mid-rib. The injured tissues turn brownish. Affected leaves become crinkled and show a distorted appearance and discolouration of buds also observed. Thrips infested tea leaves become harder and thicker compared to un-infested ones. The initial symptom of attack is light brownish discolouration of tip and basal part of leaf. The badly affected leaf exhibits a rough texture with deformed leaf curling appearance. The shoots and leaves show stunted growth and in extreme cases, the shoot may carry as many as eight leaves and still fall short of the tipping level.

Life history: The eggs are laid singly in the tissues of leaf buds and young leaves. The eggs remain completely embedded in the tissue. A female may lay 2 to 3 eggs in a day. The developmental period of the egg stage lasts for 7-8 days in March, 6-8 days in April and 6-7 days in May June. Pupation takes place in lichens and mosses growing on tea bushes but sometimes in cracks and cravices on the stems. The total duration of nymphal stages (first and second) is 6.0, 5.3-5.7 and 5.0 and 4.3 days in March-April, May and June respectively. The life cycle is completed in 17.6, 16.7, 15.4-15.6 and 13.4-13.6 days in March, April, May and June, respectively.

Varietal preferences: Some of the Tocklai-released clones like TV1 and TV2 are highly susceptible to thrips attack.

24 Integrated Management of Tea Pests

Tea thrips (Scritothrips dorsalis) -adults Damage Symptoms of tea thrips

Colony of tea thrips Damage Symptoms of tea thrips

Tea jassid/Green fly, Empoasca flavescens Fabricius (Homoptera: Cicadellidae) The tea jassid is an important sucking insect pest of tea, generally during the first and second flushes (March to June) in tea plantations of Northeast India. It is commonly known as ‘tea green fly’, ‘tea jassid’ or ‘tea leafhopper’. The pest remains active at various levels of intensity throughout the season.

Nature of damage: The insect sucks the sap of growing shoots and leaves. Nymphs and adults of E. flavescens are the most important stages that damage the tea plant and are mainly phloem feeders. Sucking of the sap of young leaves and tender shoots causes the main damage. The nymphs are responsible for greater damage than the adults. During feeding, the rostrum is inclined downwards and the stylets are inserted into the plant Damage symptoms of green tissue. They feed on the contents of the phloem vessels and flies on tea reach this tissue through cortical cells. Once penetration has started, saliva is injected into the plant. The injury to the plant is probably the combined effect of feeding in the vascular tissue and the action of certain enzymes present in the saliva. The plant sap is drawn into the alimentary canal by the activity of the cibarial sucking pump that is provided with strong dialator muscles. The attacked leaves become dry, uneven and usually curl downwards, getting inverted and boat-shaped. The margins turn brown and subsequently dry up. This characteristic symptom is known as ‘rim blight’

25 Integrated Management of Tea Pests

or ‘hopperburn’. The midrib and veins of the affected leaf also show somewhat brownish discoloration. Leaf structure and texture of clones determine the tolerance level against Empoasca spp. Because Empoasca spp. suck the sap from the phloem, their stylets must traverse the cuticle, upper epidermis, palisade tissue and spongy mesophyll. Therefore, the thickness of the palisade tissues, subepidermis and collenchymas under the main vein has a significant negative correlation with leafhopper density in tea. Thick and spongy cells physically prevent the probing of the leaf tissues by Empoasca spp. and feeding may induce the salicyclic acid and reactive oxygen species pathways, and two jasmonic acid/ ethylene-dependent defence signaling pathways. The ‘hopperburn’ and other symptoms are caused mainly by interference with the translocation of food materials and water due to the physical plugging of the xylem and the destruction of the phloem cell.

Life cycle:

Egg: The egg is elongate, somewhat narrower at one end, slightly curved with a smooth surface and measures about 0.5 mm long and 0.25 mm width. The colour of the egg is almost white when freshly laid but the later the colour changes to pale yellow.

Nymph: The newly hatched nymph is small colourless with pink eyes but soon after feeding it becomes slightly yellowish green in colour.

Adult: The adult is a small yellowish green insect, the forewings being pale yellow. The female measures about 2.75 mm long while the male is about 2.50 mm long. The eggs are embedded singly in the soft tissues of tea bushes such as mid-rib, veins of young leaves, petioles and tender Life stages of tea green fly stems. During the cold weather the eggs may occasionally be found in the older leaves. The site of oviposition can be noted by the swelling of the tissues. The incubation period is 10-13 days in March, 9-11 days in April and 6-8 days in My, June and July under the climatic conditions of Northeast India. The young nymph on hatching pushes its way out of the tissues leaving a minute hole and the tissues around the opening become discoloured. There are five nymphal instars and the total duration of nymphal instars vary from 12-15 days in March, 10-13 days in April and 8-10 days in My- June under climatic conditions of Northeast India.

Seasonal incidence: Populations of the insect occur on tea bushes throughout the year. During cold weather very few insects are found on pruned and skiffed tea bushes but a large number of them may be found in unpruned, young and nursery tea plants. The pest is more active during March to July. With the rise in ambient temperature from March the insect multiplies rapidly to assume serious proportions in May-June; the attack continuing up to July. From August, the population suddenly declines to a negligible number though there may be a slight increase in November. The attack, however commences later in Darjeeling where June and July are regarded as the “green fly” season.

Varietal preference: Tocklai released clones like TV1, TV7, TV6, TV9 are more susceptible to jassid attack. The Assam kinds of tea are generally more susceptible than China hybrids.

26 Integrated Management of Tea Pests

IPM techniques for Thrips and Green flies: • Caustic washing of the trunk of the bushes after cleaning the mosses and lichens and stirring of soil around the collar region will kill pupae of thrips. • Yellow sticky trap is found quite effective in attracting thrips, green flies and white flies in large number. Bright yellow polythene sheet of around 45 cm wide can be fixed as a band around shade tree collar just above the plucking table. A thin film of sticky material (HMPSA) should be smeared on it, so that attracted insects are stuck and killed. If there is no shade tree, the trap can be prepared by fixing the yellow sheet on both the sides of a hard board of 45 X 45 cm size and placed at 10-12 m apart at the bush canopy level with the help of a bamboo post. The trap should be placed in November in proposed unprune tea and in the end of February or early March in deep skiffed and pruned teas as soon as new shoots start coming, so that the pests can be controlled at initial stage without any insecticides. This will continue until the plastic sheet is partially damaged, when the sheet should be collected and destroyed and new sheet should be placed. Once the traps are full with trapped insects and stickiness of the gum is reduced it can be cleaned with diesel, dried for a day and the HMPSA can be smeared again. If there is no mature shade tree, the trap can be prepared by fixing the yellow sheet on both the sides of a plastic board of 45 X 45 cm size and placed at 10-12 m apart at the bush canopy level with the help of a bamboo post or thread . Avoid fixing the yellow band in very young and immature shade trees. Please keep in mind that yellow polythene sheet rapping should not be Sticky traps for tea thrips and green flies firm or air tight.

• Chemical management: Even after adopting the above measures, if the pests are found active on growing shoots in pruned and deep skiffed teas, apply first round of Quinalphos 25 EC @ 1:400 followed by Thiamethoxam 25 WG @ 1:4000/ Thiacloprid 21.7 % SC @1:1000 in alternate round. Ethion (1:400 HV) and Phosalone 35 EC (1:400 HV) may also be tried during non plucking period, which was found effective against thrips in one of the initial trial at Tocklai. In case of severe infestation combination treatment of Thiamethoxam 25 WG @ 1:4000 + Bifenthrin 8% SC @1:1600 showed better result if proper TRA recommended cultural practices are also followed. • The common plants having pesticidal property like Clerodendrum viscosum (Dhapat tita), Polygonum hydropiper (Patharua biholongoni), Xanthium strumarium (Agara), Cassia tora Vitex negundo (Pasatia) Pongamia pinnata, Sapindus mukorossi (Soapnut) etc should be applied in mixture at 10 % concentration (High volume). The fresh vegetative matters (Leaves, flowers and soft stems) should be crushed and soaked for 3-4 days followed by straining with muslin cloth, the extract from 10 kg of herbs should be mixed with 100 liter water (10 %) and sprayed. It can be applied as a routine spray, to reduce infestation of most of the common pests like thrips and green fly to a great extent. After application of these botanicals, if any pest is found active then only above recommended pesticides should be used. • Application of two rounds of TRA microbial products like Metarhizium anisoplae+Beauveria

27 Integrated Management of Tea Pests

bassiana spore suspension (1:1) @5% and Verticillium lecanii 2kg/ha+ jaggery 2kg/ha at 7 days intervals showed promising control of the red spider mite in mild to moderately infested tea fields (new experimental findings). • For effective thrips and jassid management, spraying target should be lower part of the leaf. Hand- operated calibrated knapsak sprayer is preferable for this operation.

Yellow Sticky Band/trap

Yellow Sticky Band for young and immature shade trees and non-shaded areas

Scale Insects

Scale insects belong to the families Coccidae and Diaspididae, order Hymenoptera. Those with soft scales belong to family Coccidae and those with armoured scales to family Diaspididae; mealy bugs belong to family Pseudococcidae. There are several species of scale insect observed in tea gardens and the common ones are Eriochiton these (Green) on tea stem; Fiorinia theee (Green) on tea leaf, Ceroplastes rubens (Mask ell) on tea stems. Now scale insects are the major problem of the gardens. The scales are the silent killers of bushes if not noticed on time.

Damage caused by scale insects: Scale insects feed by sucking sap from tea plants through piercing-sucking mouth parts. Sap feeding by scale insects may cause yellowing or wilting of leaves, stunting or unthrifty appearance of the plants, and eventually death of all or part of the plant when infestations are heavy. Weakened plants may lose vigor and become more susceptible to injury caused by drought, attack by other insects pest, or infection by diseases. While feeding, soft scale insects excrete a sweet, sticky substance called honeydew. Honeydew is a mixture of undigested sugar and water passed through the insect’s digestive system and deposited onto leaves and stems. Honeydew may make the plant appear shiny and wet and also attracts flies, ants, bees, and other insect scavengers. The honeydew may encourage a fungus called sooty mold that gives the plants a characteristic black, “sooty” appearance.

28 Integrated Management of Tea Pests

Life cycle of scale insects: Scale insects have a simple life. Eggs are laid underneath the scale covering of the adult female. When the eggs hatch, tiny immatures, known as nymphs. Nymphs have legs and antennae and are called “crawlers” because they walk away from the maternal scale to settle at new feeding sites. For most common scales, this is the only stage where it crawls about on the plant. When the crawlers arrive at a suitable location, they insert their mouthparts into the plant, and begin to feed on the plant’s sap. The shell or scale characteristic of the species develops soon after feeding begins. The legs and antennae of most species are lost as the nymphs grow. Nymphs and adult females for most species remain at the same location for the rest of their lives. Adult males are tiny, flying, gnat-like insects that fly to new females for mating. Scales may go through one or more generations each year.

Scale insect damage symptoms on tea plants

IPM techniques for Scale insects:

Scale insects are difficult to control because their waxy or cottony covering serves as a protective barrier to traditional contact insecticides. However, a pest management program that incorporates natural, mechanical, and/or chemical controls (as described below) should provide satisfactory control of most scale-infected tea plants. • The first and probably the most important step of scale insect management is early dictation of the pest. As they are mostly active on branches inside the bushes. Infestation is not noticeable if not checked properly. Growth of black sooty mold is also an indicator of scale infestation. • Clones like TV1, Teenali 17, and P126 etc. are more prone to scale infestation, therefore regular vigilance is required for early detection. • Although the scales are often well controlled by beneficial predators and parasites but due to climate change and over dependence of synthetic pyrethroids reduce the natural enemy population which led to enhanced scale population at present. • Field and plant sanitation are very important to minimize the pest incidence. Removal of weeds (reservoirs of pests), adequate shade, suitable fertilisers, improvement of drainage system, TRA recommended cold weather practices, ground sanitation etc. encourage the growth and vigour of the plants increasing their ability to resist attack by the insects. • Caustic washing of the trunk of the bushes after cleaning the mosses and lichens and stirring of soil around the collar region will reduce the pest incidence significantly. • As in this garden, the scale infestation is severe, we recommend thorough drenching of infested plants including all branches up to the collar region (such as the underside of leaves, stem) with following insecticides: Clothianidin 50 WDG @1:4500 (HV), thiamethoxam 25% WG @ 1:4000 (HV) and quinalphos 25 EC @1: 400 (HV)

29 Integrated Management of Tea Pests

alternatively. Mixing Agro spray oil (0.5-1%) or Sesame oil (0.5%) as an adjuvant with above mentioned insecticides can enhance their efficacy. • Before applying insecticides, make sure the plants are receiving appropriate TRA recommended cultural care and take steps to conserve natural enemies. • Use of sticker is recommended during the spraying. • Recent studies conducted by the Entomology department TRA, revealed that of Aloevera extract (5%), Himalayan salt (2%) and lime sulphur @ 1:40 + Himalayan salt (2%) had given promising result in management of scale insect on tea (New experimental finding).

Termites (Isoptera: Termitidae)

Many termite species cause considerable damage to tea bushes and shade trees. All termite colonies are governed by a caste system. Queen termites are integral to the founding and growth of termite colonies. Young and mature tea as well as cuttings in vegetatively propagated nurseries are often damaged by termites. Among the termite castes, workers are very dangerous to tea. They are responsible for major damage to young and mature teas plants especially in Cachar and North Bank areas of Assam and Dooars in North Bengal. Das (1962) reported that at least 15 per cent of the total crop is annually lost due to the attack of termites. Termites that are responsible for damage to tea bushes may be classified into two groups:

Live wood eating termites

They form innumerable oblong oval nests of about 3 cm diameter in the soil up to a depth of 40 cm. These attack living tissues of tea bushes and are considered to be primary pests of tea. They excavate galleries within the healthy wood of tea bushes. Tea plants in India are infested primarily by three species of live wood eating termites, namely Microtermes sp., Microcerotermes pakistanicus Ahmed and Microcerotermes spp. Live wood eating termites are smaller than the scavenging termites.

Damage symptoms of live wood eating termites

Scavenging termites:

They have their nests in mounds or underground. The height of the mound is about one meter and diameter is 30-50 cm. These generally attack dead and dying tissues and are regarded as secondary pests of tea. There are six species of scavenger termites, namely Odontotermes assamensis Holm, O. parvidens K & N Holm, O. feae (Wasm), Coptotermes heimi (Wasm), Neotermes buxensis Roonwal and Sen Sharma, and Capritermes sp.

30 Integrated Management of Tea Pests

Damage symptoms of scavenging Scavenging termite Live wood eating termite termites mound nest

Nature of damage:

Nature of damage caused by both the scavenger and the live wood eating termites is similar, but the injury caused by the former is slower and confined to a few unhealthy mature bushes, while the injury caused by the live wood termites is rapid and occurs in more or less severe form in young as well as in mature sections. The scavengers first attack the dead wood, resulting from fungal or borer attacks, under cover of earth runs, and also extend the damage to the adjacent healthy tissues by removing the dead wood. The live wood-eating termites attack the tissues of the bark of healthy young bushes. Once they get entry, they excavate fine tunnels into the hearthy wood and either hollow out the stem, leaving only a thin layer of wood and bark or replacing the whole woody part with earth materials leaving the bark outside

IPM techniques of tea termites:

The main hindrance in termite control in tea plantations is that not a single chemical termiticide is approved in PPC. Control Measures A. Cultural Practices • Bushes should be properly cleaned out at the time of pruning by removing snags as well as dead and diseased branches. Any earthen materials like earth runs over the trunk and stems and earth depositions on the collar of the bushes should be wiped out/ removed at the time of pruning. • Pruning cuts should be painted with indopaste or copper fungicide or Trichoderma bio- cide. Remains of old shade tree stumps inside the sections should also be cleaned and treated or removed permanently. • Hollowed out or badly damaged branches should be cut out. • Destroy termite mounds and queens. Mound sites should be thoroughly dug out as deep as possible to remove the honeycomb chambers, earthen cells and galleries. All soils from the mound sites must be removed from the plantation areas. • Caustic washing of the bush frame in the cold weather • Periodical soil stirring during the cold weather in flat areas • The soil within a radius of 30 cm from the collar of the bushes should be cleaned of grass, weeds, etc. • Improve drainage in the termite prone fields. • Improve shade status of the tea fields.

Palliative Measures Termites are very active during cold weather. Hence, effective measures should be taken

31 Integrated Management of Tea Pests up after the pruning operations are over. After pruning, the top, middle and lower hamper of the bushes are clearly visible when control measures could be taken up effectively. Slight stirring / forking of the soil around the collar will be beneficial for easy percolation of the insecticidal solution and disturbance of termite nest. • Thiamethoxam 25 WG should be applied to the ground as well as on the collar and branches at a dilution of 1:4000 at the rate of 250 ml of spray fluid per young plant (below five years) and about 500 ml per mature tea bush. The spray fluid should be preferably applied by means of plastic cans or with hand sprayer without nozzle. • In droughty areas, chemical treatment should be preceded or followed by irrigation. • 3. If the pre-treatment operations are properly done between end December and February followed by the application of pesticides, then one can expect to get fairly good control. In case of severe infestations repeat applications may have to be done for 2-3 years. • In case of termite prone organic garden, in September – October during initial infestation, the sections due for pruning should be treated with Metarhizium anisopliae (2 × 107 cfu/g) @ 10% or entomopathogenic nematodes (Heterorhabditis indica) @ 7 kg/ha and during December – February, another round of spray with the same fungus on the ground around the collar region (volume of spray fluid is same, as mentioned above). • Recent studies conducted by TRA suggested that the control of termite (control >75%) achieved by following non-conventional means: ◦◦ Boric acid (1%) + Thiamethoxam (1:4000) ◦◦ TRA Metarhizium anisopliae (5%) + Boric acid (1%) ◦◦ TRA Metarhizium anisopliae (1%)+ Thiamethoxam (1:4000) ◦◦ TRA Beauveria bassiana (5%) + Boric acid (1 %) ◦◦ Boric acid (2%) ◦◦ Entomopathogenic Nematodes (EPN: Heterorhabditis indica) (@7kg/ha) ◦◦ EPN 5 kg/ha + Boric acid (1 %) ◦◦ Thiamethoxam (1:4000) + TRA Beauveria bassiana (5% ) ◦◦ Aqueous extract of Ipomea carnea (10%) ◦◦ TRA Metarhizium anisopliae + TRA Beauveria bassiana ( 5 % + 5%)

Prophylactic Measures

1. New extension and replanting: In new extension or replanting areas all the woody materials as far as practicable should be removed. If the area is known to have termite problem, it is advisable to put insecticidal solution into the bottom of the planting pit and again after filling the pit. This will help in preventing the termite infestation. 2. Nurseries: While preparing the beds for tea nursery, Thiamethoxam 25 WG solutions may be applied at 1: 4000 dilution to prevent the attack of termite, cockchafer, cutworm etc. For cuttings in sleeves, spraying can be done as a precaution against termite attack.

Non-conventional termite management: These non-chemical approaches have shown promising results in the management of termites:

32 Integrated Management of Tea Pests

TEA WHITEFLY (Hemiptera: Aleyrodidae)

A new species of whiteflies belonging to the genus Tetralicia (Hemiptera: Aphelinidae) is presently being reported to cause severe infestation on tea plants, particularly in the south bank of Assam. The symptoms of damage are very similar to jassid infestation with the affected leaves becoming uneven and curling downwards. Occurrence of Tetralicia sp. was reported earlier from other plants like Cinnamomum but this is the first report of its occurrence on tea. The insects have been found to take shelter on the ventral surface of the tea leaves. The life cycle typically consists of egg, 3-4 nymphal stages called instars, the pupa and adult. The first nymphal stage (crawler) is barely visible even with a hand lens. The crawlers move around for Whitefly on the ventral surface of tea leaves several hours before settling to begin feeding. Latter nymphal stages are immobile, oval, and flattened, with greatly reduced legs and antennae and appear like small scale insects. The winged adult emerges from the last nymphal stage (sometimes called a pupa). All stages feed by sucking plant juice from leaves and excreting excess liquid as drops of honeydew as they feed. Excessive use of synthetic pyrethroids in tea may be one of the reasons for the invasion of this new species of insect pests. Management of heavy infestations is difficult. In many situations, whitefly populations in the early stages of population development can be checked by adopting a vigilant program of removing infested leaves or hosing down with water sprays. Yellow sticky traps can be used Symptom of whitefly damage to monitor and to reduce whitefly numbers.

Whitefly catches on yellow polythene sheets Whitefly catches on yellow sticky traps

33 Integrated Management of Tea Pests

Preparation of Plant based biopesticides at the garden level.

Collection of plant material

Dry under shade

Powder by grinding

Pass through a 20 mesh sieve and keep in a 1 kg. capacity polypropylene bag (may preserve for 10-12 months)

Soaking: 5 kg. powdered material in 50 litres of water along with 1 kg. of soapnut# powder for 1 day followed by vigorous stirring*

Filter through double layered muslin cloth

Make up of volume by 100 liters and addition of surfactant**

5% extract is ready for spraying

[*For the preparation of 10% plant extract, soak 10 kgs. of powdered material in 50 liters of water overnight. Next morning after filtration by double layer muslin cloth make up the volume to 100 liters by adding required amount of water. For spraying 1 ha area (400 liter of water), 40 kg plant powder is required for preparation of 10% extract. # Soapnut powder acts as an emulsifier. ** 1 kg. jaggery (molasses) mixed with 400 liters of plant extract.]

34 Integrated Management of Tea Pests

Acknowledgement Some of the images depicted in this bulletin have been provided by: • Prof. Ananda Mukhopadhyay, North Bengal University • Mr. A.S. Nain, Goodricke • Mr. P.K. Murari, McLeod Russel • Mr. A.H. Chaudhary, Goodricke • Mr. Niraj Mani Chaurasia, Goodricke Their help in the preparation of this bulletin is duly acknowledged.