Gram Pod Borer Control

Symptoms

Young larvae scrape the leaves and feed on tender foliage, giving leaves a scorched, papery look. As they grow, larvae bore circular holes into pods and thrust only the front half of the body inside while the rest hangs out, eating the developing grains. Damaged pods show clean round holes and empty grain chambers. The caterpillar varies in colour from green to brown with light and dark stripes along the body.

Damage

Helicoverpa is the single most damaging pest of chickpea and pigeonpea in India and can cause 30 to 60 percent pod loss in unprotected crops, sometimes a complete loss in severe outbreaks. A single larva can damage 30 to 40 pods during its life. Because it bores directly into grain, even a small population causes high economic loss.

Organic & cultural control

Install pheromone traps at 5 per acre to monitor moth flights and time control. Put up bird perches at 20 to 25 per acre so birds pick up caterpillars. Spray HaNPV (Helicoverpa nuclear polyhedrosis virus) at 250 LE per hectare in the evening when larvae are young. Spray neem seed kernel extract 5 percent or neem oil. Apply Bacillus thuringiensis on young larvae. Grow marigold as a trap crop and hand pick large larvae early in the morning. Conserve natural enemies like Trichogramma and Chrysoperla.

Chemical control

When larvae cross the economic threshold (1 to 2 larvae per plant or per metre row), spray recommended insecticides such as emamectin benzoate 5 SG, chlorantraniliprole 18.5 SC, indoxacarb 14.5 SC, spinosad 45 SC or flubendiamide. Rotate chemical groups to avoid resistance, as this pest develops resistance fast. Always read and follow the product label for dose, water volume and pre-harvest interval, and consult your local KVK or an agronomist before spraying.

Always follow the product label, the recommended pre-harvest interval, and your local KVK or agronomist. Pesticide approvals change, so verify before use.

Prevention

Grow tolerant or early maturing varieties to escape peak pest periods. Do deep summer ploughing to expose and kill pupae in the soil. Sow on time and avoid excess nitrogen which makes plants lush and attractive. Use intercropping of chickpea with mustard or linseed and grow marigold borders. Scout the crop twice a week from flowering and start control at the threshold rather than waiting.