Banana Weevil

What it looks like

Adults are hard, dull black weevils about half an inch long with a long snout. Grubs are legless, cream colored, and curled, with a reddish-brown head.

Damage

Grubs tunnel through the corm (the underground stem base), cutting off water and nutrients. Plants grow poorly, bear small bunches, and can topple in wind.

How nematodes help

The eggs, grubs, and pupae live in the corm, at and below the soil line, where nematodes can reach them. Adults hide in the soil and plant debris at the base of the plant.

In greenhouse tests in Puerto Rico, Steinernema nematodes killed all the grubs. Field results with S. carpocapsae (the nematode in Ecomask) have been mixed, and the adult weevils are hard to infect. In lab tests, S. feltiae (the nematode in Scanmask) and Heterorhabditis nematodes also killed the grubs.

In university research, the timing that worked best was year round in warm climates, whenever grubs are present. Treat at planting, and after harvest when the stems are cut.

How to apply

Treat with Ecomask. Scanmask also works.

When: Anytime the larvae are active.

Where: Drench the soil around the plant base and corm. Pour into cut stumps and pseudostems (the trunk-like stems) after harvest.

See How to apply for step-by-step directions, or use the calculator on the Ecomask Spray page to see how much you need.