Chilli

Insect Management

Detailed Study of Insects

Aphids: (Aphis gossypii & Myzus persicae)

Seasonal Occurrence

• Generally seen when the plants are in reproductive phase.

Life Cycle

The pest is active from May to November. Adults live 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.

Ecology

• Multiplying fast during December-January.
• Occurs mainly in dry and cloudy weather cool and humid conditions are favourable for multiplication while heavy rains wash away the aphid colonies.

Nature and symptoms of damage

• Appear on the tender shoots, leaves and on the lower surface of the leaves.
• Suck the sap and reduce the vigour of the plant.
• Secrete sweet substances which attracts ants and develops sooty mould. The pods that develop black colour due to sooty mould lose quality and fetch low price.
• The yields are also reduced by aphids directly and more through the spread of virus diseases acting as vectors indirectly.

Control

• Spray with 0.1% Dimethoate or Methyl demeton (2 ml in one litre of water) or Monocrotophos 1.5ml or Acephate (1g in one litre of water)
• Spray with alternate chemicals at 10 days interval till the end of aphid population checked.
• The winged forms of aphids migrate from one field to another rapidly.
• Hence, spraying is to be done as far as possible within a day or two by all the cultivators of particular locality.

Mites (Polyphagotarsonimus latus)

Seasonal Occurrence

• Of late, mite has developed as a major problem in chilli cultivation.
• It is making its appearance in the nursery itself after 40 days of sowing.
• In the main field it gains spread during the month of November.

Life Cycle

• There are four distinct stages in the life history of the mite viz., egg, larva, nymph and adult. The eggs are minute and oval in shape and are laid on the ventral surface of young leaves or on leaf buds.
• After hatching, the minute pearshaped white larva having 3 pairs of legs move sluggishly. During the nymphal stage, transformation of larvae into adult takes place.
• The adults measure 0.1 mm in length and bear 4 pairs of the legs. They are yellowish green in colour and translucent in nature. The egg, larval nymphal and adult period occupies 1.5 – 2, 1.5, 1 and 8-10 days, respectively. Both sexual and arrhenotokus reproductions have been observed in mites, There is no over wintering in the mites.

Ecology

• From the point of longivity and reproduction early winter is more favourable for adult forms and mid winter for apterous forms are observed in large number.
• They are responsible for spreading the infestation from plant to plant and establish new colonies.

Nature and Symptoms of damage

• Nymphs and adults suck sap from leaves.
• Affected leaves curl downward along the margins of the leaf and attain an inverted boat shape.
• Leaf petioles elongated and small leaves serrated and looks like buncy appearance.
• Leaves turn to dark grey in colour and reduce leaf sheath, stops flowering and considerable yield reduction.
• In severe cases fruit wall becomes hard and white strips appears on the fruit.

Control

• Spray Phasalone 3ml/litre (Severe conditions) Or Wettable sulphur 3g/litre of water or Dicofal 5ml/lit of water.

Thrips(Scirtothrips dorsalis)

Life Cycle

• Eggs laid inside the tissue of the leaves and shoots.
• Egg period is 5 days.
• Single female can lay 2-4 eggs/day.
• Egg laying capacity is 40-70 egg/female.
• Nymphal period is 7-8 days.
• Pre pupal and pupal period is 18-24 hours and 48-56 hours respectively.
• Four instars are seen.
• Adult lives for 10-15 days.
• Thrips are minute, slender and crawling on leaves and flowers.

Ecology

• Pest infestation increases in dull weather

	Seasonal Occurrence Thirps appears in Nursery (July - August) and mainfield (November).
	Nature and symptoms of damage Both adults and nymphs damage the crop and lacerate the leaf tissue and suck the sap. Major pest on chilli crop affecting the plants throughout its life period starting from nursery. Tender shoots, buds and flowers are attacked as a result they become twisted and deformed, upward curling of leaves are seen· Attacked plants are stunted, leaves dropped, fresh buds become brittle and drop down.
Control Spray Carbaryl 0.15% (3g/ litre of water) or Phasalone 0.1% (3ml/litre or water) or Methyl demton 0.05% (2ml/litre) or Acephate 1g/litre or Triazophos 1ml or Fipronil 2ml or Monocrotophos 1.5ml/lit of water. For every spraying change the pesticide and spray at fortnight intervals four weeks after transplanting.

Fruit Borers (i) Tobacco caterpillar (Spodoptera Litura)

Seasonal Occurrence

• In chilli the caterpillar mostly damages the fruits by boring into it.
• This coincides with post rainy season viz., November onwards.

Life Cycle

• Tobacco caterpillar adult is brown in colour.
• It lays eggs in clusters of 40-200 and covered with brown hairs and a female can lay about 2000 eggs.
• The eggs hatch in 3-4 days.
• The caterpillars will fully grow within 20-40 days and measures 3-5 cm in length.
• It is greenish or pale brown in colour with broken dark brown stripes along the body.
• When it is young it is generally green.
• Later it turns to dark green or violet.
• It pupates in the soil within 17-24 days, the adult moth comes out.
• The total life cycle is completed in 43-63 days.

Ecology

• After December, particularly after heavy rains, heavy infestation develops.
• Fruit borers are polyphagous and appear on chilli crop both in vegetative phase and at the time of pod formation.
• Among the pod borers, spodoptera litura is major and does maximum damage to chilli crop.

Nature and symptoms of damage

The larvae of second and third instar enter chilli pods by making a hole near calyx and feed on chilli seed. The affected pods drop off or develop white colour on drying.

Control:

• All the pod borers are nocturnal in habit and can be seen during day time also in the early stages.
• It is easy to control when they are seen in numbers on the same plant feeding on leaves making small holes.
• Spray Chlorpyriphos 2.5ml/litre of water or Quinolphos 2ml/litre of water or Endosulphan 2ml or Carbaryl 3gm or Monocrotophos 2ml or Thiodicarb 1gm or Acephate 1g/litre of water are recommended.
• Keep Pheromone traps (2/acre) in the field to attract the male moths by which the intensity of pod borers in the environment can be known.
• Poison baiting with 5kg bran, 500gms Jaggery and 500gms carbaryl or 500ml Monocrotophos or chlorpyriphos mixed with water small pellets should be made and applied in the evening times in the field. In the right times larvae come out, eat and die is promising against grown up caterpillars which withstand contact insecticides as sprays.
• In case the conventional insecticides fail to control the pod borers the usage of Synthetic pyrethroids is to be resorted too.
• Don't spray synthetic pyrethroids more than twice, as they induce flare up of sucking pest complex.

Gram caterpillar (Helicoverpa armigera)

Seasonal Occurrence

• Mostly seen from November onwards when the chilli plant enter into reproductive phase.

Life History

• Female moth lays shiny, cream coloured eggs singly on tender parts of the plant.
• Each moth lay 700 - 3000 eggs. Eggs hatch in 3-4 days.
• For full development of larva about 3 weeks time is required.
• Pupation takes in soil for 10-12 days. There may be 7-8 generations per year.

Ecology

• Insect is very active in post - rainy season, (October to March) which coincides with reproductive phase of chilli crop.

Nature and Symptoms of damage Larvae damages by boring into fruits and feeds on inner contents of the pods. The entry hole is large and typically circular. The affected pods drop off. Control measures Similar control measures can be taken up as in Tobacco Caterpillar.

Ragi cut worm (Spodoptera exigua)

Seasonal Occurrence

• Very intensive during December - January period.
• Masses of eggs laid by the insect on the leaves.

Life Cycle

• Moth lays eggs on the bottom side of leaves.
• Egg hatch in 5-6 days larval stage varies 22-25 days.
• Pupation lasts for about 7-9 days.
• Longivity of adult is about 7-10 days.

Ecology

• Heavy rains after a prolonged drought results in wide spread multiplication and larval development.
• Heavy application of Nitrogen favours the development of pest.

Nature and Symptoms of damage

• Mostly damages the leaves, flowers and tender pods. Damage to matured pods is minimum.

In severe cases the insect causes damage to twigs also. It feeds the fruit at the base of the calyx.

Control

• Weeds belongs to Amaranthus category acts as alternate hosts, hence, removal of such weeds reduces the infestation.
• Collect the egg masses and destroy.
• It webs the leaves and hide inside during day time.
• Hence, for effective control spraying operations should be carried out in the evening hours.
• Spray Chlorpyriphos 3ml/litre of water or Monocrotophos 1.6 ml/litre of water or Quinalphos 2ml/litre of water for controlling this insect.

Root grub (Holotrichia consanguinea)

Seasonal occurrence

• Large numbers of newly hatched larve in June shows that this insect becomes active with the onset of monsoon.

Life Cycle

Adult beetles lay eggs singly upto a depth of 10cm. Eggs hatch in 7-10 days. Newly hatched grub develops in 8-10 weeks. Grubs are white, having brown head and prominent thoraxic legs. After the monsoon the full-grown larvae migrate to a considerable depth in the soil for pupation Pupa is a semi-circular and creamy white and the pupal stage lasts for about fortnight. Adults formed in November and remain in the soil at a depth of 10-20 cm and come out for feeding at night. Adult beetles are dull brown. Pupation is maximum in the rainy season and there seems to be only one generation in a year. Ecology Partly decomposed organic matter encourages the grub multiplication. Optimum soil moisture with sufficient organic matter is congenial for beetles to lay eggs. 30-35°C is optimum soil temperature for pupation.

Nature and symptoms of damage

Grubs eat away the nodules the fine rootlets and may also girdle the main root, ultimately killing the plants. The attacked plants can be easily identified and pulled out easily. Root grubs generally prefer young plants and their damage can be seen in the field upto the end of October. At nights the beetles feed on foliage and may completely defoliate the plant.

Control

• To prevent root grubs, only well rotten farm yard manure should be used along with 100kg neem cake per acre.
• Before sowing (July-August) use 20 kg of 2% Folidol dust.
• In case of severity apply 10 kg Phorate granules per acre thoroughly mixed up to 15cm deep in the soil.
• Seed treatment of insecticides for the control of white grubs, Phorate 10G 50g a.i/kg of seed or Quinalphos 5G @ 50g a.i/kg of seed.
• For treating the seeds with granular insecticides, slurry of clay was prepared and the mixture of this slurry and the required quantity of the granular insecticide were put into earthen pot and shaken to have uniform coating over seeds.
• After the treatment, seeds were dried in shade.
• Application of insecticides in the standing crop for the control of white grubs - Carbaryl 50% W.P 0.2% Or Isofenphos 5G @ 25kg/ha. Or Quinalphos 25 E.C 0.02%
• To control white grubs use of plant products like mustard seed powder @ 60 kg/acre or Neem seed powder @ 80 kg/acre.
• Use of plant products provides wide range of safety to the ecosystem, keeps away the crop from the Phytotoxic effect as well as from residual toxicity and pollution.

Root – Knot nematode (Meloidogyne javanica)

• These Nematodes are very minute and are not visible to naked eye, but they will cause considerable damage and inturn affect the yields.
• The survival media of nematodes generally is soil.
• During intercultural operations, they are transmitted by soil and irrigation water.
• They invade fine roots and make knots on the roots, hence the root knots appeared as a root nodule of legume / pulses.
• They block the movement of nutrients and water in the plant system and subjected to wilt and finally leads to death.
• Yellowing of the foliage and wilting of the upper leaves.
• Remove the affected plant as and when noticed along with infected soil of root zone and burn.
• Restrict the movement of irrigation and ploughing operations from infected fields to healthy fields.
• Select good resistant variety.
• 2-3 years crop rotation with other than solanaceous crops like Jowar, Maize & Bajra.
• Apply 50kg carbofuran 3G granules per acre after transplanting nearer to root zone by placement method.
• Apply 15 cart loads of FYM along with 250 kg of Neem cake per acre and incorporate into soil before transplanting.

Whitefly (Bemisia tabaci)

Seasonal Occurrence

• Highly Polyphagous, generally appears from November to February.

Life Cycle The insect breeds throughout the year and the female lays stalked yellow spindle shaped eggs singly on the lower surface of the leaf. Eggs hatch in about a week's time.

• The Nymphal stage remains attached on the lower side of leaves and takes about 4 weeks to complete development.
• Number of generations varies between 12-15 per year.
• Nymphs are Oval, Scale like and remain attached to the leaf surface. Adults are tiny, moth like with yellowish body and wings coated with milky white waxy powder.

Nature of Damage

• Nymphs and adults suck the sap usually from the under surface of the leaves and excrete honey dew causing contamination of the lint.
• Leaves appear sickly and get coated with sooty mold.
• It also transmits the leaf curl virus.

Ecology

• Temperatures around 30°C with high humidity favours multiplication of pest.
• Economic threshold level : 8-10 adults or 20 nymphs / leaf.

Other Hosts

• Brinjal, Tobacco, Tomato and Cotton.

Control

• Whiteflies can be effectively attracted and controlled by yellow sticky traps, which are coated with grease and sticky oils.
• Spray Triazophos 2ml/litre of water or Prophanophos 2 ml/litre of water.
• Use of Synthetic Pyrethroids increase the intensity of Whitefly.
• Spraying of any Neem product (5% Neem oil before egg laying) or 5 kg Neem Kernel extract per acre with any sticky material.