Major Insects of chilies and its control

Chili Pests (Major)

Chili Thrips: Scirtothrips dorsalis

Two spotted spider mite

Tetranychus urticae

Green peach aphid Myzus persicae

Armyworm Spodoptera litura

Fruit borer Helicoverpa armigera

Minor/ Occasional Pests

Flea Beetles

Leaf miner Liriomyza sativae

Whitefly Bemesia tabaci

Insects at different crop stages

Crop stage

Possible pets

Vegetative stage
Seedling stage	Thrips, Mites, Aphids
Branching	Thrips, Mites, Aphid
Reproductive stage
Flowering	Thrips, Mites, Aphids
Fruiting	Fruit borers (Spodoptera litura), (Helicoverpa armigera)

ETLs for chili pests

      (Nursery)           

      Aphids 2/seedling          

                Thrips    5/seedling          

      Vegetable (Field)            

      Aphids 4/leaf   

      Thrips    9/leaf   

      Fruit borer (Helicoverpa Sp.)       50% fruit attacked

      Army worm        8 egg masses/100 meter

Mites 1-2 mites for leaf at vegetative phase of crop. 2-3 mites per leaf in advance stage of growth.

Chili Thrips: Scirtothrips dorsalis

•       Pest of economic significance

•         pepper, mango, citrus, strawberry, 

•       grapes, cotton, tea, peanuts, blueberry, and roses.

•        Feed preferentially on new growth

•       Wrinkled leaves, with distinctive brown scarring along the veins of leaves, the buds of flowers, and the calyx of fruit.

•        Prolonged feeding by thrips curls tender leaves and buds, and will turn fruits and flowers from bronze to black in color.

Population Attributes  of Thrips

Vagile (excellent invaders, mobile)
◦ Broad host range
◦ Short generation time
◦ A competitive breeding structure promoting aggregation and exploitation of localized optimal conditions

Life History

      30 to 40 days for a complete generation

      6, 5, and 5 days for development of egg, larva, and pupa

      Pollen doubles or triples fecundity

      Strong aggregation tendencies

      Scirtothrips aggregate on young foliage and flowers

Management of thrips

      Management of S. dorsalis in the landscape requires an integrated approach that includes a detailed understanding of pest biology, natural enemy complexes, and host resistance.

      Chemical control options are also available and may be necessary in some cases. 

      Chemical control options or destruction of plant material is the only option for retail nurseries as long as S. dorsalis remains a regulated pest.

• Monitoring for adults

                                White sticky boards

                                floral tapping on white paper

•  Insecticides      

Pymetrozine (25SC, 400ml/ 100 L of water/acre 

Diaphenthiron(50SC, 250ml/100 L of water

Spinetoran 12SC, 40-60 ml/100 L of water

Fipronil 5SC 300ml/ 100 L of water

Prevention better than cure

      Do not grow chilli after sorghum – more susceptible to thrips

       Do not follow chilli and onion mixed crop – both the crops attacked by thrips

       Sprinkle water over the seedlings to check the multiplication of thrips

Chilli Thrips Natural Enemies

      Egg Parisitoid

      Megaphragma sp. (Chalcidoidea)

      53.2% parasitism on grapes in Japan

      Predatory Mite

      Euseius sojaensis

      1.4 larvae/hr

      5.4 larvae/day

Various group of predatory insects and mites play important role in natural control of thrips. The chrysopids, coccinellids, Orius spp.ants and spiders are important predators of thrips.

Important Worldwide Predators of Thrips

ORDER HEMIPTERA

FAMILY ANTHOCORIDAE

    commonly, pirate bugs

GENUS Orius

SPECIES insidiosus

COMMON NAME

    Insidious flower bug

PEPPER

Intrinsic capacity of Orius insidiosus to reduce thrips populations

Predator-Prey Ratios

1 : 217 = population suppression

1 : 51 = rapid local extinction

Aphid:

Biology

The pest is active from 2^nd week of transplanting and after 5^thweek of transplanting. Adults lie for 2 –3 weeks and produce 8-22 Nymphs per day. Both winged and wingless forms breed parthenogenetically. The nymphal period lasts for about 7-9 days. It has 12-14 generations per year.

Nature and symptoms of damage

      Nymphs and adults of aphids suck the cell sap from the under surface of the leaves and growing shoots.

      They secrete honey-dew on which black sooty mould develops on leaves and young shoots.

      The black coating affects the photo-synthetic activity of the plants.

      Leaves curl, internodal length shortened, wiping of leaves, leaf size gets reduced, growth gets retarded.

      Important insect vectors of chilli mosaic

      Mosaic disease transmitted by aphids cause 20-30 per cent loss in yield.

Problem and its Management

      Multiply fast during December – January occur mainly in dry and cloudy weather cool and humid conditions are favourable for multiplication. While heavy rains wash away the aphid colonies.

      Pruning

      Check transplants for aphids before planting

      Tolerant varieties

      Reflective mulches

      Sturdy plants can be sprayed with a strong jet of water

      Insecticides only required to treat aphids if the infestation is very high

      insecticidal soaps or oils such as neem or canola oil are usually the best method of control; always check the labels of the products for specific usage guidelines prior to use

Mites

      Tiny creature that live on foliage, buds and fruits

      Mostly on the lower surface of leaves in a protective web

      Under severe infestation, the leaves curl downwards

      Fruits turn brownish with hardened skin

                Thrive in dusty conditions; water-stressed plants are more susceptible to attack

Management of mites

      In the home garden, spraying plants with a strong jet of water can help reduce buildup of mite populations

      If mites become problematic apply insecticidal soap to plants

      Certain chemical insecticides may actually increase mite populations by killing off natural enemies and promoting mite reproduction

      Removal of infected branches through pruning

• Pruning old
• Post-harvest application insecticide/miticides such as endosulfan
• Spray dicofol 18.5 EC @ 2.5 ml/ lit or wettable sulphur 50WP @ 5 g m / lit of water Encourage the activity of predatory mite: Amblyseius ovalis

Helicoverpa armigera

•       Eggs

•       Laid singly on host plant.

•       Spherical in shape with a flattened base, giving dome shaped appearance, surface is sculptured in the form of longitudinal ribs.

•       Yellowish-white, glistening and change to dark brown, before hatching.

•       A  female lays about 500-3000 eggs.

•       The egg period is 7 days

Larva

•       Newly hatched caterpillar is sluggish and whitish-green in colour.

•       Full-grown larva is 3.5-4.0 cm in length with pale-green body colour. However, the colour varies according to the food intake.

•       Dorsal surface bears dark broken stripes.

•       Head is reddish-brown.

Shows colour variation from greenish to brown

•          Pupa – 

It pupates in soil in earthen cell, leaf, pod and crop debris .

Freshly formed pupa is greenish yellow in colour and darkened prior to emergence of moths.

Adult     

•          Female light pale brownish yellow 

•          Male – Pale greenish moth V shaped speck

•          Forewing – olive green to pale brown with a dark brown circular spot in the centre

•       Hindwing-   is pale smoky white with a broad

•       blackish outer margin

•       Female moth is bigger than male and presence of tuft of hairs on the tip of the abdomen.

Symptom of damage

•       In the early stages, plants seen defoliated.

•       Boreholes seen on the damaged fruit and affected fruits unfit for consumption.

Nature of damage

•       Young larva feeds on tender leaves, buds, flowers, and subsequently it bores into the fruit and thrust only a part of its body into the fruit and eat the inner content, the rest remaining outside.

Management

•          Collect and destroy the infected fruits and grown up larvae.

•          Planting of 2 rows of African marigold as trap crop with every 14 rows of chillies

•          Installation of H armigera pheromone traps @ 4/ha to monitor the initial attack of pest or  setup pheromone trap with Helilure at 15/ha for mass trapping

•          Six releases of T. chilonis @ 50,000/ha per week coinciding with flowering time or innundative release of Trichogramma @ 2, 50,000 parasitized eggs/ha at 10 days interval at the beginning of flowering and fruiting

•          Release Chrysoperla carnea at weekly interval at 50,000 eggs or grubs / ha from 30 DAS.

•          Leufenuron (Match 50 EC). 200ml/acre; Chlorantraniliprole 20 SC, 50ml/acre or Spinosad (Tracer 24 SC), 40ml/acre to control early instar larvae

Do not spray insecticides after fruit maturity.

Army worm Spodoptera litura

Identification

•       Adult moth is stout with wavy white markings on the brown forewings and white hind wings with a brown patch along its margin.

•        Eggs are laid in groups usually on ventral side of the tender leaves and covered with brown hair.

•       A single females lays on an average 400 eggs (maximum 2000) in 3 to 4 clusters, each of 80-150 eggs.

•       The egg period is 4-5 days. Larva is stout, cylindrical, pale brownish with dark markings.

•       The body may have row of dark spots or transverse and longitudinal grey and yellow bands. When fully grown, measures about 35-40 mm in length.

•       The larval period is 14-21 days. It pupates in earthern cells in soil for 15 days.

•       Life cycle is completed 30-40 days.

Symptoms of damage

•       Freshly hatched caterpillars feed gregariously, scrapping the leaves from ventral surface

•       Greenish caterpillars feed on the leaves voraciously and present an appearance to the field as if grazed by cattle.

•       Since this pest is nocturnal in habit it hides under the plants, cracks and crevices of soil and debris during the day time.

•       Feacal pellets are seen on the leaves and on the ground which  is the indicator of the pest incidence.

Management of Army Worms

•       Monitor the emergence of adult moths by setting up of light traps.

•       Set up pheromone trap to monitor, attract and kill the male moths @ 12 nos./ha and change the septa once in 3 weeks.

•       Collect egg masses and destroy.

•       Collect the gregarious larvae and destroy them as soon as the early symptoms of lace-like leaves appear.

•       Avoid migration of larvae by digging a trench 30 cm deep and 25 cm wide with perpendicular sides around the infested fields.

•       Marigold is a suitable intercrop/border crop for fruit borer management apart from harboring activity of major parasitoid of the fruit borer parasitoids Microplitis sp, Cotesia sp., Campoletis chlorideae and a polyembryonic parasitoid, Copidosoma sp.

•       Grow castor as a border (or) intercrop (or) trap crop and  set up

•       pheromone trap (Spherodin SL) to monitor, attract and kill the male moths @ 12 nos./ha for  Spodoptera litura.

•       For managing Spodoptera litura spray Leufenuron (Match 50EC) 200ml/acre, Chlorantraniliprole 20 SC, 50ml/acre or Spinosad (Tracer 24 SC), 40ml/acre to control early instar larvae  (1st to 3rd instar). 

•       Do not spray insecticides after fruit maturity.

Common Beneficial Insects

Coleoptera

- Coccinellidae; lady beetles

Aphids

thrips

Carabidae; ground beetles

Weed seeds

Lepidoptera eggs