Nature of Damage:
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This insect attacks the crop at flowering stage and also at the maturity of the capsules.
The larvae bore into the capsules and damage the seeds and the peduncles. Occasionally the larvae also bore at the junction of the petiole and lamina of the leaf.
At the site of larval entry into the capsule, a silken gallery is made. The larva is always found under the cover of silk and frass or excreta.
The gallery forms a protective covering for the larva. The freshly hatched larva bores into stem if eggs are laid on the axil below the inflorescence.
This insect can damage 7-14 % plant, 4-20 % inflorescence, 16-82 % of the heads which may reduce 9-23 % of yield.
Management:
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Mechanical collection and destruction of attacked shoots and capsules may reduce the pest incidence.
Diadegma ricini Rao and Kurian, D. trochanterate (Morley), Theronia sp.,Bracon hebetor Say, Can be used as larval parasites.
RC 1377 - Highly susceptible, Aruna & JI- 144 – Tolerant. The variety having purple colour of stem and smaller seed size (Aruna) were tolerant to this pest than the varieties having green stem and bigger seed size.
Spraying the crop with monocrotophos 0.04 % or carbaryl 0.2 %.