Description:
The adult is about 1/4 inch long, shiny and slender bodied for a weevil,
appearing almost ant-like. The middle of the body and the legs
are red and the rest of the body is blue-black. Larvae are elongate but slightly
C-shaped in appearance, legless and dirty white to gray in color with a distinct
head capsule that is yellow-brown in color. Few other weevils would be confused
with sweetpotato weevil.
Life Cycle:
The life cycle can continue throughout the year in stored sweet potatoes.
All stages may be found almost anytime. Eggs are deposited singly in a small
cavity that the female eats in stems or sweet potatoes or in cracks or crevices.
Larvae hatch in about a week and take 2 to 3 weeks to develop through several
stages (instars) in good conditions. A generation takes about one month to 6 weeks.
Adults can fly well with reports of over a mile and they may live up to 8 months.
Pest Status:
A pest of sweet potatoes because the larvae tunnel into tubers,
attacking living plants in the field and continuing to develop in stored
sweet potatoes; damaged tubers develop a bitter taste and a bad odor;
Control:
Uproot and destroy all morning glory plants in the
vicinity of the sweet potato field. Most morning glory plants are perennial.
All efforts should be made to uproot them to prevent regrowth.
Since weevil eggs, larvae and pupae may be living in the stems,
destroy morning glory vines by burning.
Eliminate land cracks. Weevils travel through land cracks to gain access
to storage roots and lay eggs. These cracks are caused by the underground
storage roots becoming larger and larger. Land cracks may also be caused
by lack of soil moisture, which is common in the dry season.
