University of Nebraska-Lincoln
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University of Nebraska-Lincoln |
 Photo Credit: North Carolina State University | Billbug |
| Description: | Adults are grey, dark brown or black weevils, depending on species, measuring ¼ - ½ inch long. Adults often are hard to see in the field; their coloration is similar to the soil and they ‘play possum’ when disturbed. Larvae are white, legless grubs, about 5/8 inch long at maturity. |
| Damage Symptoms: | Adults feed on seedling corn at the base of the plant. They can kill small seedlings or damage the growing point, causing twisting of the stem, stunting, and tillering. Minor damage may result in rows of circular holes on leaves are they come out of the whorl. Larvae bore in the stalk at the base of the plant. Larval damage reduces yield. |
| Incidence: | One generation a year. Adults active at corn emergence and for 4-6 weeks thereafter. |
| Sampling Scheme: | Examine plants for damage starting at emergence; often damage may be more severe on field borders or low lying areas of a field. |
| Economic Threshold: | If 5% of plants are killed or severely injured by billbugs a postemergence insecticide may be warranted. |
| More Information and Treatment Recommendations: | http://www.unl.edu/entomology/extension/crops/fieldcorn.shtml |
