Pod Borer (Maruca vitrata)
It feeds on the seeds of the damaged pods and also the larvae creates holes in the pod. The crop is infested from early budding stage and the eggs are laid on the flowers leading the larvae to enter the flowers. The caterpillars roll the leaves and web these with top shoots. It can be efficiently controlled by spraying Carbaryl 50 WP thrice at intervals at rate of 2g/L. The plant can also be dusted with Carbaryl 10D at rate of 2.5 kg/ha. It can also be controlled by spraying 2ml/L of water of Endosulphan or Thiodan or Malathion. Neem Seed Kernel Extract at 5% can also be applied if population exceeds.
Bean Weevil (Acanthoscelide obtectus)
The adult weevils lay eggs on stored seeds and larvae bore into the seeds and feed on them till they mature. It leads to formation of holes which ultimately decreases the germination potential of the seeds. It can be curbed by fumigating the seeds with phosphine gas which is available in form of Celphos and Phosfume tablets, which can be applied at rate of 1 or 2 tablets per tonne of seed.
Whitefly (Bemisia tabaci)
The eggs are laid on the underside of the leaves which hatch in 8 days and they feed on the sap by sucking it. Early morning vacuuming of the plant so that the adults are unable to lay eggs is a control measure for small areas. It can also be controlled by placing yellow stick traps with castor oil which attracts the insects and they stick on the trap. It can also be controlled by spraying 0.25% Metasystox or Rogor in early crop stage.
Diseases and Management
Alternaria Leaf spot (Alternaria alternata)
Forms small irregular brown coloured lesions on leaves which gradually turns gray brown with larger circles. The lesions collectively forms large necrotic patches. Plants which are grown in nitrogen and potassium deficient soils are more susceptible to this disease. It may lead to premature defoliation of leaves causing reddish brown lesions which merge into long streaks that develop on the pods.