Strawberry Rootworm
(Paria fragariae Wilcox)
Fact Sheet No.199, UMaine Extension No. 2370 

Description

The adult strawberry rootworm is a shiny, oval beetle 1/8-inch long.  Its color may vary from brown with four darker blotches on the back to solid black (Photo 1and 2).  The adults feed on the plants chiefly at night and are not commonly seen during the day.  The larvae are white and are found in the soil.

Life Cycle

The adults spend the winter in ground litter or in other protected places and begin to become active in early May.  The largest numbers of beetles occur between late May and early June.  Eggs are laid during this period and developing larvae burrow into the ground, where they feed on the roots of strawberries and other related plants.  They become pupae in the soil, and new adults emerge from mid-July through August and feed on foliage the rest of the season.

Damage and Economic Importance
This beetle is more commonly a pest of strawberries, but can also damage blueberry plants in Maine.  Infestations are usually confined to isolated areas.  The most severe damage is caused by the adult beetles, which eat holes in the leaves.  When adults are abundant, leaves are riddled with holes giving the plants a ragged appearance.

For information regarding monitoring and control, contact the lowbush blueberry specialist, University of Maine Cooperative Extension, 1-800-897-0757 (toll-free in Maine) or 207-581-2923.

Prepared by Judith A. Collins, Assistant Scientist, and H. Y. Forsythe, Jr., Professor of Entomology, in cooperation with David Yarborough, Extension Blueberry Specialist, The University of Maine, Orono, ME 04469. February 1996.