European chestnut weevil
(Curculio elephas (Gyllenhal, 1836))

Overview

Origin

The chestnut weevil, Curculio elephas, is a weevil native to southern and central Europe, which feeds on the seeds (nuts) of chestnuts and oaks.

Life Cycle

Adult weevils emerge from the soil in August and September and cause feeding damage by piercing nuts with their long, slender snout. After feeding, female weevils turn around and deposit one to several eggs in each nut through the feeding hole. Upon hatching, the larvae or "grubs" consume the nut meat. Kernels of infested nuts are often completely eaten. After feeding inside the nut for about a month, the larvae chew their way out of the nut and enter the soil. They remain in the soil as larvae over the winter, pupating in late June. The complete life cycle requires one year.

Distribution

Curculio elephas has been intercepted many times on species of chestnut and other plant taxa being imported into the United States.

Control Efforts

Populations of chestnut weevil can be suppressed by good cultural and sanitation practices. In home plantings, nuts should be gathered daily as soon as they fall and stored so that emerging weevil larvae cannot enter the soil to reinfest. If all newly emerged larvae are destroyed for a period of 3-4 consecutive years, weevil populations can be reduced to tolerable levels. Three to four applications of insecticide beginning about 7-10 August, and repeated at 10-day intervals, will provide control of adult chestnut weevils.

Selected Images

Maps

Invasive Listing Sources

• South Carolina Plant Pest List
• USDA APHIS Regulated Pest List