During active growth stage, groundnut crop is infested with sucking pests and defoliators.
Among the defoliators, groundnut red hairy caterpillars, cause devastating effect on the crop by devouring the leaves.
Adult moths emerge from the soil with the onset of the monsoon.
A female moth lays about 600-700 cream coloured eggs in groups mostly on the under surface of the leaves and occasionally on other vegetation. Incubation period ranges from 2-3 days.
Larval periodGrown up caterpillar is reddish brown with a black band on either end having long reddish brown hair all over the body. It is the destructive stage of the pest. Larval period lasts for 40-50 days.
Pupation takes place along field bunds or in moist soil at a depth of 10-20 cm where they undergo pupal diapause for about 10-12 months. Adults are medium sized moths having white wings with brownish streaks.
Early instar larvae feed voraciously by scraping the under surface of the tender leaves. Grown up larvae feed voraciously on entire foliage, flowers and growing points. They often migrate from field to field in search of food after devastating the foliage in the field where they have hatched. Severely damaged crop gives the appearance of having been grazed by cattle.
Control measures— Collect and destroy the egg masses and voracious early instar larvae.
— The pupae may be collected at the time of summer ploughing and destroyed.
— Set up bonefires or light trap up to 11.00 P.M. after receipt of summer showers to attract and kill the moths.
— Dig the trench around the field at 30 cm depth and 25 cm width to check the movement of migrating larvae.
— To check early instar larvae spray phosalone 35 EC at 300 ml/ac.
— For grown up caterpillar spray fenitrothion or chlorpyriphos at 600 ml/ac in 300 lt of water.
(Dr. J. Ramkumar is Assistant Professor and Dr. R. Durai Singh is Programme Coordinator, Krishi Vigyan Kendra, Tamil Nadu Agricultural University, Ramanathapuram – 623 503, email: arsramnad@tnau.ac.in, Phone: 04567-232639.)
