GREEN FRUIT WORMS
The GREEN FRUIT WORMS (helicoverpa) is the most common of several green fruit worm pests occurring in commercial orchards of Himachal Pradesh. The fruit worms are the larvae of different moth species. These larvae are the pests of apple fruit present as green caterpillars. The larvae feed on fruit trees including apple, pear and cherry. Small larvae feeds on young leaves, buds, flowers and finally on the fruit. They create deep pits in the apple fruit. The adults of green fruit worm are brown in color and about 1 inch long. The larvae are green with light colored stripe through its back when fully grown. They are usually kept under control by spraying insecticides at pink bud and petal fall stage.
The damage is done when the larvae of green fruit worm feeds on the apple fruit. However feeding on fruit does not affect the health of the tree but, can make the fruit quality poor. At half-inch green stage females starts laying their eggs on the twigs and the leaves. They deposit one or two eggs at a single site; however they are capable of laying hundreds of eggs. Young larvae feed on leaves and flower buds whereas older larvae damage flower and continue to damage the developing fruit. The damage is common on those orchards where pink bud or petal fall sprays are not done or if pesticides are applied that are not effective against them.
There is one generation per year. The green fruit worm overwinters as a pupa in the soil. Adults emerge from late March to early May and lay eggs on tree leaves. Larvae begin to hatch in April and climb to the tips of spurs where they feed and grow. They prefer fruiting spurs and often hide themselves by rolling the leaves together with silk. They feed at first on buds, then later on flowers, leaves and fruit. In summer, mature larvae drop to the ground and burrow into the soil to pupate.
To get rid off from fruit worms one should do sprays both at pink bud stage as well as petal fall stage, and use pesticides which are effective against them. Bacillus thuringiensis sprays is an organic management to control green fruit worms. Spraying Diazinon during delayed dormancy or at petal fall controls populations of green fruit worms. Spraying flubendamide has also been found effective in controlling fruit worms.