Billbugs on Corn

The billbug is another serious pest of corn in South Carolina. Actually, there are three different species of billbug that attack corn in this state. They are the southern corn billbug, the maize billbug, and the corn billbug. All three may infest a single field. These pests are capable of completely destroying a stand of corn in only a week or two.

Billbugs are robust, black or brown beetles ranging from 1/5 to 3/4 inch in length. All have a curved snout about 1/3 their body length. They use their snout to chew into the stalk and feed on the tender inner tissue. Bud leaves then wilt and die.

Southern corn billbugs, the most serious of the  three in this state, may or may not lay their eggs in and around the corn. Native grasses such as marsh grasses and nutgrass are preferred hosts of this species. It is suspected that they overwinter in weeds and grasses around fields, then move into corn as it emerges in the spring. Control of weeds and grasses both in and around fields would be a preferred control measure for this pest.

The maize billbug lays its eggs in the corn stalk. The grubs then eat out the inner stalk, after which they make a hollow cell in the taproot in which they pupate. After emergence, the adults remain in that cell until spring, at which time they leave the soil at just about the time when most of the corn emerges. Since corn is the preferred host of the maize billbug, proper crop rotation is both the cheapest and most effective means of controlling this pest.

The corn billbug is not usually a major problem in South Carolina.

Most species of billbugs rely upon crawling in order to get to a new field if corn does not follow corn. If no corn fields are nearby or if grassy or weedy areas are used as barriers, damage can be reduced. Fields of small grains or a strip of densely planted corn may also act as barriers.

A banded application of a recommended insecticide at planting is an effective control measure against billbugs. However, since the list of labeled products is constantly changing, and since available products varies from state to state, there will be no mention of specific products. With all insecticides, read and follow label instructions carefully.

Prepared by Donald G. Manley, Extension Entomologist/Professor, Department of Entomology, Soils, and Plant Sciences, Clemson University.

This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. Brand names of pesticides are given as a convenience and are neither an endorsement nor guarantee of the product nor a suggestion that similar products are not effective. Use pesticides only according to the directions on the label. Follow all directions, precautions and restrictions that are listed.

The Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, sex, religion, national origin, disability, political beliefs, sexual orientation, marital or family status and is an equal opportunity employer. Clemson University Cooperating with U.S. Department of Agriculture and South Carolina Counties. Issued in Furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of May 8 and June 30, 1914.