Insect Pests of Fruit, Plantation, Medicinal & Aromatic Crops (2+1)

1. Rhizome weevil

1. Rhizome weevil - Cosmopolites sordidus Germ. (Curculionidae: Coleoptera)

Damage

• The grub bore into the sucker and tunnel into the rhizome resulting death of the unopened leaves at the heart of the plant is called "pipe" and withering of outer leaves. A result of severe attack, the plants show pre - mature withering.
• Scarcity of leaves and production of under sized fruits.
• The corm of infested plants has extensive tunnels plugged with excreta.
• High incidence of pest occurs during April - October.

Damaged pseudostem   

Damage
Bionomics

• The adult weevil is stout measuring 12.5 mm in length and 4.5 mm in width and dark brown. in colour.
• It lays its eggs in small burrow made on the plant at ground level.
• The incubation period is 5-8 days. The grub is apodus and yellowish with reddish head.
• The larval period is about 25 days. It constructs a pupal chamber near the surface of corm and change into pupa within.
• The pupal period is 6 days. The adult has long life and can remain alive for one year.
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Grub

Management

• Trap adult weevil with pseudo stem chopped into pieces
• Uproot and destroy the infested rhizome from the field.
• Use pest free suckers for planting.
• Apply carbofuran 3 G 10 gram per plant at the time of planting.
• Trap adult weevils with corm chopped into small pieces and kept near infested clump at 65/ha (Banana corm split trap) or use cosmolure traps at 5/ha.
• By paring and pralinage method, apply carbofuran 3 G 40g or phorate 10 G 20g; or apply lindane 1.3 D 20 g or carbaryl 10-20 g/ sucker before planting.
• Dip suckers in monocrotophos 0.05% and plant 24 h later.