Chilli insect pests

Gram pod borer

It is a polyphagous, infesting gram, lablab, safflower, chillies, groundnut, tobacco, cotton etc.

Biology:

• Egg: The spherical, yellowish eggs are laid singly on tender parts and buds of plants. The egg period lasts for 2-4 days.
• Larva: Caterpillars vary in colour, initially brown and later turn greenish with darker broken lines along the side of the body. The larval period lasts for 18-25 days. Body covered with radiating hairs. When full grown, they measure 3.7 to 5 cm in length. The full grown caterpillar pupates in the soil in an earthen cell and emerges in 16-21 days.
• Pupa: Pupation takes place inside the soil. Pupal stage lasts 7-15 days.
• Adult: Moth is stout, medium sized with brownish/greyish forewings with a dark cross band near outer margin and dark spots near costal margins, with a wing expanse of 3.7cm.

Life cycle:

Damage symptoms:

• Young larva feeds on the leaves for some time and then attacks fruits. Internal tissues are eaten severely and completely hollowed out. While feeding the caterpillar thrust its head inside leaving the rest of the body outside.
• Bored fruits with round holes.
• Fed leaves, shoots and buds.
• The activity of Helicoverpa starts on greengram, summer vegetables and maize and continues their generation by Aug-Sept months synchronizing with main crop.

Tobacco caterpillar

It is found throughout the tropical and sub tropical parts of the world, wide spread in India. Besides tobacco, it feeds on cotton, castor, groundnut, Chilli, cabbage and various other cruciferous crops.

Biology:

• Eggs: Female lays about 300 eggs in clusters. The eggs are covered over by brown hairs and they hatch in about 3-5 days.
• Larva: Caterpillar measures 35-40 mm in length, when full grown. It is velvety, black with yellowish – green dorsal stripes and lateral white bands with incomplete ring – like dark band on anterior and posterior end of the body. It passes through 6 instars. Larval stage lasts 15-30 days.
• Pupa: Pupation takes place inside the soil. Pupal stage lasts 7-15 days.
• Adult: Moth is medium sized and stout bodied with forewings pale grey to dark brown in colour having wavy white crisscross markings. Hind wings are whitish with brown patches along the margin of wing.

Life cycle:

Damage symptoms:

• Pest breeds throughout the year.
• Moths are active at night.
• Adults live for 7-10 days. Total life cycle takes 32-60 days.
• There are eight generations in a year.

Spider mites

Life cycle (Tetranychus spp.)

Damage symptoms:

• The infested leaves develop crinkles and curl downwards
• Elongated petiole
• Buds become brittle and drop down.
• Early stage, infestation leads to stunted growth and flower production, fruit set are arrested

Root-knot nematodes

Biology:

• Most species of plant parasitic nematodes have a relatively simple life cycle consisting of the egg, four larval stages and the adult male and female. They are microscopic in size.
• Development of the first stage larvae occurs within the egg where the first moult occurs. Second stage larvae hatch from eggs to find and infect plant roots or in some cases foliar tissues.
• Under suitable environmental conditions, the eggs hatch and new larvae emerge to complete the life cycle within 4 to 8 weeks depending on temperature.
• Nematode development is generally most rapid within an optimal soil temperature range of 70 to 80°F.

Life cycle:

Life stages are microscopic in size

Damage symptoms:

• Infected plants in patches in the field
• Formation of galls on host root system is the primary symptom
• Roots branch profusely starting from the gall tissue causing a ‘beard root’ symptom
• Infected roots become knobby and knotty
• In severely infected plants the root system is reduced and the rootlets are almost completely absent. The roots are seriously hampered in their function of uptake and transport of water and nutrients
• Plants wilt during the hot part of day, especially under dry conditions and are often stunted
• Seedlings infected in nursery do not normally survive transplanting and those surviving have reduced flowering and fruit production
• Nematode infection predisposes plants to fungal and bacterial root pathogens

Survival and spread:

• Primary: Cysts and egg masses in infected plant debris and soil or collateral and other hosts like Solonaceous, Malvaceous and Leguminaceous plants act as sources of inoculum
• Secondary: Autonomous second stage juveniles that may also be water dispersed

Favourable conditions: Loamy light soils

Thrips

Biology:

• Egg: Hyaline, globular laid in mass.
• Nymphs: Nymphs tiny, slender, fragile and straw yellow in colour.
• Adult: Adults with heavily fringed wings

Life cycle:

1. Eggs are microscopic

Damage symptoms:

• The infested leaves curl upward, crumble and shed
• Infested buds become brittle and drop down.
• Affected fruits show light brown scars
• Early stage, infestation leads to stunted growth and flower production, fruit set are arrested

Host-range and favourable conditions:

• S. dorsalis is found in almost all chilly growing areas. It is a polyphagus pest. Besides chilli, it also infests brinjal, cotton, groundnut, castor, bottlegourd, guava, tea and grapevine. It is more common on un-irrigated chilli crop than irrigated one.

Spider mites/Yellow mites

Biology

• Egg: Eggs are oval shaped eggs and white in colour. Eggs are glued firmly on the leaf surface.
• Nymph: Nymphs white in colour.
• Adult: Adults large, oval and broad and yellowish in colour.

Life cycle (Polyphagotarsonemus latus):

Damage symptoms:

• Both nymphs and adults suck sap and devitalize the plant causing ‘Murda’ disease of chillies.
• Infestation results in downward curling of leaves,
• The affected leaves becoming inverted boat shaped,
• The leaves rolling down along the margin with elongation of petioles.
• Affected leaves turning dark green in certain cases.
• Younger leaves at the tip of branch clustering.

Aphids

Biology:

• Eggs are very tiny, shiny-black, and are found in the crevices of bud, stems, and barks of the plant. Aphids usually do not lay eggs in warm parts of the world.
• Nymphs (immature stages) are young aphids, they look like the wingless adults but are smaller. They become adults within 7 to 10 days.
• Adults are small, 1 to 4 mm long, soft-bodied insects with two long antennae that resemble horns. Most aphids have two short cornicles (horns) towards the rear of the body

Life cycle:

Damage symptoms:

• Appear on the tender shoots, leaves and on the lower surface of the leaves.
• The honeydew is very sweet which attracts sooty mould growth, making the leaves turn black.
• 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

IPM for Chilli

To know the IPM practices for Chilli, click here.

Source: NIPHM and Directorate of Plant Protection, Quarantine & Storage