5. Leaf eating caterpillar

5. Leaf eating caterpillar - Spodoptera litura Fab. (Noctuidae: Lepidoptera)

    Damage
    • Young caterpillars of both the insects bore into the tomato fruits while they mature. The Helicoverpa larva remains partly out on the fruit hole while eating, where as the Spodoptera caterpillar can be seen remaining wholly inside the fruit. The bore holes are generally plugged with excreta.
    Bionomics
    • H.armigera – The adult moths are marked with characteristic ‘V’ shaped speck on the light brownish fore wing and a smoky dark border on the hind wing. It lays spherical yellow colour eggs singly on tender parts of plants. It has very high fecundity which may go up to 3000 eggs/female. They hatch 4-8 days and the caterpillars may start feeding on young foliage and later move to the young tomato fruits. There is a remarkable change of colour as the caterpillar passes from one instar to another. It pupates in an earthern cocoon in soil. Pupal period is 10-25 days.
    • S.litura – The adult moths are stout with grayish brown alternated with white markings on the fore wing while the hind wings are radiantly white with a brown border. The eggs are laid in masses and covered with brown hairs on the surface of the affected leaves. The young caterpillars are voracious and may start feeding on young foliage and finally they migrate to young fruits. Laval period is 2-3 weeks. Pupation takes place in an earthern cocoon in soil.
    Management
    • Collect and destroy the infested fruits from the field.
    • Collect the egg masses of S.litura and destroy them.
    • Collect and destroy the larvae of the H.armigera and S.litura.
    • Set up light traps to attract and kill the moths of both pests.
    • Set up pheromone traps @ 12 / hectare to attract the male moths H.armigera and S.litura.
    • Release an egg parasitoid Trichogramma chilonis for 6 times @ 50,000 / hectare / week, first release coinciding with flowering time and based on ETL of 4-6 moths / six pheromone traps.
    • Spray NPV of H.armigera at 450 LE per hectare + cotton seed kernel powder 300 g/hectare thrice. Each application should be followed by Trichogramma releases.
    • Spray NPV of S.litura at 250 LE per hectare in the evening hours.
    • Prepare poison bait (Rice bran 12 kg/Jaggery 2.5 kg + carbaryl 50 WP 1.25 kg and water 7.5 litres / hectare) and keep the bait in the evening hours to attract the cater pillars of S.litura.
    • Grow simultaneously 40 days old America tall marigold and 25 days old tomato seedlings at 1.16 rows.
    • Spray endosulfan 35 EC 2 ml / litre or carbaryl 50 WP 2 g/litre or Bacillus thuringiensis @ 2 g. / litre or quinolphos 2.5 ml / litre of water.

Last modified: Tuesday, 7 February 2012, 11:44 PM