The whitefringed beetle, Naupactus leucoloma, is a conundrum because there is so much variation in the population. There seem to be a number of species involved in the "whitefringed beetle complex," but as there are no male whitefringed beetles in North America, crosses are impossible to make so they are all lumped together as "whitefringed beetles." Naupactus minor, Naupactus peregrinus, and Naupactus fecundus are also called whitefringed beetles although if cross-breeding were possible, they might all prove to be the same species. Adults are light to dark gray or brown, usually with a light band along the outer margins (the white fringe), and two pale lines or blotches along each side of the thorax and head. They are about ¹/₂ inch long. Whitefringed beetles are flightless but may may crawl up to ³/₄ of a mile. Eggs are deposited in masses held together by a sticky substance that hardens upon drying. They are usually laid on or just below the surface of the soil. Whitefringed beetle larvae are C-shaped, pale, fat, legless grubs that grow up to ¹/₂ inch long. Grubs overwinter and continue feeding before pupating in the soil the following spring. Emergence begins in May and continues throughout the summer. Adults live for two or three months. Each female can lay 600 to 700 eggs. There is one generation per year although some grubs may not pupate until their second spring.

Whitefringed beetles chew on the edges of leaves.

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Whitefringed beetles chew on the edges of leaves.

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Whitefringed beetle grubs are about half an inch long.

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Whitefringed beetle grubs are about half an inch long.

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Whitefringed beetles have been found feeding on 385 species of trees, shrubs and ornamental plants as well as vegetable and field crops. Adults often feed gregariously, and as many as 200 or 300 beetles may be found on one plant. Adults feed on the edges of leaves rather than chewing holes. However, the most serious damage to plant health is caused by the grubs feeding on roots.

Whitefringed beetle grubs attack underground portions of plants.

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Whitefringed beetle grubs attack underground portions of plants.

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Because whitefringed beetles are parthenogentic, selection for resistance is not likely to happen. Most of the insecticides labeled for landscape use should give adequate control. Consider using one of the pyrethroids as they tend to have longer residual activity. When used as directed, pyrethroids are very toxic to insects but are not particularly hazardous to humans and pets (other than fish—avoid using pyrethroids around pools, ponds, and streams).

• Common name: whitefringed beetles, scientific name: Naupactus (=Graphognathus) spp. (Insecta: Coleoptera: Curculionidae). Dixon, W. N. 2008 (revised). Featured Creatures, Entomology & Nematology, FDACS/DPI, EDIS, University of Florida. Publication Number: EENY-294
• Whitefringed Beetle, Scientific name: Naupactus leucoloma (Boheman); Naupactus minor (Buchanan); Naupactus peregrinus (Buchanan). O'Sullivan, J. No Date. Sweetpotato DiagNotes: A Diagnostic Key and Information Tool for Sweetpotato Problems,
• Whitefringed beetles (Naupactus spp.) (Coleoptera: Curculionidae). Anonymous. No Date. Forest Pest Insects in North America: a Photographic Guide
• Insect and related pests of vegetables. Sorensen, K. A. and J. R. Baker eds. 1994. North Carolina Agricultural Extension Service publication AG-295. 180 pp.
• Extension Plant Pathology Publications and Factsheets
• Horticultural Science Publications
• North Carolina Agricultural Chemicals Manual

For assistance with a specific problem, contact your local N.C. Cooperative Extension center.

This Factsheet has not been peer reviewed.