Blueberry Leaf Beetle
(Pyrrhalta vaccinii (Fall))
Fact Sheet No. 203, UMaine Extension No. 2369

Description

The blueberry leaf beetle adults range in color from brownish-yellow to reddish-brown (Photo 1).  The larvae are light greenish-gray and are about 1/8-inch long when fully grown.  The yellowish pupae are found at least one inch deep in the soil.

Life Cycle

Blueberry leaf beetles pass the winter as adults hidden in the debris at the base of blueberry plants.  They leave their winter quarters in late April to begin to feed on expanding leaf buds and to mate.  The largest numbers of beetles occur on the foliage between May and early June.  Eggs are deposited in crevices at the base of plant stems from late May to late July.  When the eggs hatch, the larvae eat the foliage of blueberry plants.  The larvae pupate in the soil, and a new generation of adults becomes common in late July.  They feed on the foliage well into the fall before seeking overwintering sites.  

Damage and Economic Importance

Adults and larvae of the blueberry leaf beetle damage blueberry plants by eating the lower surface of the leaf, leaving a lacy network of fine veins; this is called "skeletonizing."  The upper surface later turns brown.  Infestations are usually confined to isolated areas and abandoned or poorly managed fields.  However, when the beetles are very abundant for two or three successive seasons, they may kill blueberry plants over large areas.

Pest Management 

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. November 1995.