http://www.indg.in/agriculture/agricultural-best-practices/organic-production/red-gram

Important pests and diseases

The eggs of Helicoverpa are round and yellowish green in colour. Larvae emerge from these eggs on warm summer days (at temperature of about 32-33oC), which can grow up to 3.5 to 4 cm in 15-20 days. These larvae voraciously feed on leaves and can eat entire leaf tissue except the veins. A larva can damage up to 20 pods in its life span, before transforming in to pupa. The pupae are brown in colour and up to 1 cm long. Moths emerge from these pupae in about months' time. Moths continue to reproduce year round causing damage to the crops throughout the year except during hot summer. Helicoverpa survives on 181 host plants across different seasons, including cotton and legumes. Red gram is its preferred choice.  Birds and parasitic insects predate on the larva. Other insects grow either earlier or all through the cropping season.

Pod borer or Boll worm (Helicoverpa), aphids, jassids, thrips, mites etc are some of the important insect pests of red gram. Fusarium wilt disease can also be a serious problem in some places. Among them, Boll worm is most damaging and is of major concern.

Pest Life cycle

The eggs of Helicoverpa are round and yellowish green in colour. Larvae emerge from these eggs on warm summer days (at temperature of about 32-33oC), which can grow up to 3.5 to 4 cm in 15-20 days. These larvae voraciously feed on leaves and can eat entire leaf tissue except the veins. A larva can damage up to 20 pods in its life span, before transforming in to pupa. The pupae are brown in colour and up to 1 cm long. Moths emerge from these pupae in about months' time. Moths continue to reproduce year round causing damage to the crops throughout the year except during hot summer. Helicoverpa survives on 181 host plants across different seasons, including cotton and legumes. Red gram is its preferred choice.  Birds and parasitic insects predate on the larva. Other insects grow either earlier or all through the cropping season.

Economical threshold limit (ETL)

About 1-2 caterpillars per sq. m or 5-10 % pod damaged. ETL can be assessed by using the number of insects trapped in pheromone traps, light traps or on yellow traps.

Pest Management

Habitat management and cultural practices

Biodiversity is a key component in keeping the pest's population below ETL. Plant farm bunds with trees of Neem, Babul, Pongam, Sesban, Gliricidia etc. to get much leaf litter. Intercropping of red gram with soybean, Moong, ground nut, sorghum/maize and random planting of marigold and Hibiscus subdariffa (Lal ambari) helps in keeping the pest population under ETL.

Jaggery powder (10 kg/ ha) is sprayed on the soil surface, to attract ants that predate on larva.

About 10-12 bird perches are installed in one ha attracts birds that predate on the pests. Yellow rice (1 kg rice cooked with turmeric powder) kept on or near perches attract predatory birds.

Inundated release of Chrysoperla 5000 eggs after 15 days of sowing and Trichogramma 50,000 eggs (2-3 cards) after 30 days of sowing can keep the problem of pests below ETL.

Control measures

If the pest exceeds ETL, the following control measures can be adopted:

1. 2-3 Sprays of 5% Neem seed kernel extract (NSKE) at an interval 15 days. NSKE enriched with 5% cow urine has been found to be more effective. The Azadirachtin in the NSKE controls the boll worm and other sucking pests. Alternatively, 20 kg of Neem leaves boiled with 100 liter water can also be used.

1. Alternatively, Garlic, Chili and Neem crushed in cow urine can be sprayed on leaves.
   

Caterpillars can also be controlled by spraying 500 – 1000 ml HNPV per ha.

Other Pests – Rats rarely infest Red Gram field but wild boar commonly damage it near forest tracts. Fence the farms and spread the cut human hair along the border. When the boars intrude, they inhale the hair, which causes nasal irritation and sniffing. Burning of old leather also keeps the wild boars away.