Commercial products named on this site are for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable. The sweetpotato weevil, Cylas formicarius, is the most serious pest of sweet potato throughout the tropics and subtropics. While the adult weevil does minimal damage while feeding on the tuber surface or foliage, the larvae feed inside the roots and stems, often destroying entire tubers. Even slightly damaged roots are usually unsuitable for human consumption due to an off-flavor that develops as a result of the partial damage.
Female weevils look for exposed roots to lay their eggs.
The roots are usually found through cracks in overly dry soil. The female makes a small hole through the skin of the tuber and lays her eggs. The larvae that develop feed inside the root. Some eggs are also laid in the stem, but the resulting larvae feeding inside the stem only rarely reduce the yield. Sweet potato weevils live and feed on all the Ipomea species, including the various morning glory varieties that are often found as weeds in the fields.