Insect Pests of Vegetable, Ornamental and Spice Crops (2+1)

Tobacco caterpillar and Others

4. Tobacco caterpillar, Spodoptera litura (Noctuidae: Lepidoptera)

• Distribution: Tthrough out the tropical and subtropical parts of the world
• Host plants: Atacks tobacco, castor, cruciferous crops, tomato, chrysanthemum, gladiolus and many other plants.

Damage:

• Damage is caused by the caterpillars
• Early instars feed gregariously
• Scrapping the chlorophyll content from the leaves and skelotonising them
• Later instars scatter and feed voraciously eating the entire leaf

Life cycle

• Eggs hatch in 3-5 days
• Larvae become full fed in 15-30 days
• Six larval stages.
• Pupal stage lasts for 7-15 days
• Total life cycle in completed in 32-80 day
• Many overlapping generations in a year.

Salient features

• The pest breeds throughout the year
• Lay eggs in cluster covered with brown hairs
• Newly emerged larvae feed gregariously
• Older larvae disperse to feed individually on the foliage
• Pupate in soil

Management:

• Collect early gregarious larval instars and destroy them before they got scattered.
• Spray the crop with deltamethrin (0.0028%)
• Repeat the spray as and when required

5. Cutworms
Important species:

• Agrotis segetum
• A. ipsilon

• Family: Noctuidae
• Order: Lepidoptera
• Distribution: All over the world
• Hosts: Polyphagous

Damage: (Also see insect pests of cole crops)

• Damage is caused by the caterpillars
• Attack mainly the newly grown gladiolus plants
• Larvae feed during night on emerging shoots
• Also attack the under ground corms thus causing the yellowing of leaves

Life cycle:

• Moths are active during night and lay 200-350 eggs/ female.
• Oviposition continuous for 5-10 days.
• Incubation period varies from 2-12 days
• Larvae are nocturnal
• They cut the newly grown plant at the ground level and feed on the tender leaves
• Caterpillars also feed on the underground corms

Management:

• Light traps help in collecting and killing of adults.
• Use of poison bait consisting of carbaryl (0.1%) or malathion (0.1%) in wheat bran and molasses.
• Deep ploughing exposes larvae and pupae
• Drenching of infested area with chlorpyriphos (0.04%) help in controlling the larvae.

6. White grubs

• (For details see insect pests of potato)

7. Blister beetles

• (For details see insect pests of beans)