Scientific name: Cosmopolites sordidus
Synonyms: Banana beetle, banana borer, banana rhizome weevil, banana root borer, banana root weevil, banana weevil borer, corm weevil, plantain root borer, plantain weevil
Banana, plantain, and Manila hemp
The larval feeding damage starts at the outer sheaths of the pseudo-stem with several tunnels into the surface tissues. The larva continues feeding into the inner sheaths, then bore into the plant's base, roots, and rhizomes. The feeding tunnels are filled with dark colored debris and can be found along the entire length of the pseudostem. Young suckers have curled or rolled unopened leaves.
Heavily infested ones have dull yellowish green and withered leaves. Older plants have yellow and floppy leaves with small fruits.
The eggs are laid singly in chewed cavities either at the base of the pseudostem, on the corm, and/or on the roots near the soil surface. Eggs are white, sausage-shaped, and 2 mm in size. Egg development lasts for about 5-7 days.
The larva is a white, fat, and legless grubs. It has a curved body with a reddish-brown or pale-orange head and is about 12 mm long upon maturity. The larval period lasts for about 20-25 days (Mau; Kessing, 1993).
The pupa is white and without a cocoon. It is about 12 mm long and is found where the larva has been last feeding. The pupal stage lasts for 8 days.
The adult is dark brown to black in color, has a long snout and a hard shelled-body. It can live for sometime without food but will die within 2 days in a dry environment. It thrives well in moist places.
The weevil densities are higher in mulched areas. Its life span is up to 2 years.