Pests
Diamondback moth (Plutella xylostella)
The caterpillars feed on the leaf epidermis and later make holes in the leaves. Severely affected leaves are completely skeletonised.
Control: Spraying malathion (0.1%) and trap cropping with mustard controls the pest.
Leaf webber (Crocidolomia binotalis)
Caterpillars web up the leaves and live inside the knotted mass affecting flowering and pod formation adversely.
Control: Removal and destruction of webbed bunches of leaf and dusting the crop with quinalphos 0.25% or spraying with malathion (0.05%) is effective.
Cabbage borer (Hellula undalis)
The caterpillars mine the foliage, feed on the shoots and finally bore into the stem; and the infested plants get killed or produce side shoots, which do not form heads.
Control: Spraying the crop with malathion (0.1%) or dusting 4% carbaryl gives good control of the larvae.
Cabbage butterfly (Pieris brassicae)
The larvae feed gregariously on the foliage and burrow into the heads, making it unfit for marketing.
Control: The caterpillars should be hand picked and destroyed. Spraying malathion (0.1%) or carbaryl (0.15%) gives excellent control of the pest.
Aphids (Brevicoryne brassicae, Myzus persicae, Lipaphis erysimi)
Nymphs and adults suck cell sap devitalizing the plants and the affected parts become discoloured and malformed.
Control: Spraying of malathion (0.1%).
The insecticide application should be stopped 15-20 days before harvest.