Description and Biology
Pales weevils, Hyolbius pales, overwinter as adults in the forest floor litter. (The common name is pronounced PAY-leez.) This is a very dark, elongate, oval insect up to 1/2 inch long with indistinct to distinct gray or pale orange spots of scales on the wings and thorax. Pales weevil grubs are typical legless weevil grubs with white bodies and brown heads. The adults are active in warm weather at night and hide during the day. In spring, the adults feed at night on the thin bark of conifer seedlings or near the tips of branches of larger plants before they fly to cut, damaged or recently dead pines to breed. After mating, females burrow underground to lay their eggs on the roots of these stumps and trees. They chew small niches and lay one to three eggs in each. New eggs are oval and white. Grubs tunnel downward in the roots as they mature. When mature, each grub fashions a cocoon or wood chips and pupates inside it. A new generation of weevils emerges in late summer or fall. Depending upon timing and altitude, we may have two generations of pales weevils per year in North Carolina.
Pales weevils breed in all species of pines, hemlocks, junipers, spruces, firs and cedars. It likely attacks any conifer growing near an area where pines or other conifers are harvested. The pales weevil is the most serious insect pest of pine reproduction in cutover pine land, but it readily invades landscapes. When pales weevils feed on bark, they eat it down to the wood and often girdle twigs that flag and dieback. White, crystallized resin that resembles sugar forms over the wounded twig.
Other than two parasitic fungi, little is known about biological control of pales weevils. Pyrethroid insecticides should protect conifers from weevil attack. These should be applied just as soon as the damage is first noticed. Pyrethroid insecticides labeled for landscape use are available in the plant sections of big box stores and nurseries.
- Pales Weevil. Anonymous. 2017 (update). PennState Extension.
- Pales Weevil. Day, E. and S. Salom. 2014. Virginia Polytechnic Institute and State University ENTO-103NP.
- Weevils. Hoffard, W. H. 2004 (update). Forest Pests: Insects, Diseases & Other Damage Agents.
- Extension Plant Pathology Publications and Factsheets
- Horticultural Science Publications
- North Carolina Agricultural Chemicals Manual
For assistance with a specific problem, contact your local Cooperative Extension Center.
This Factsheet has not been peer reviewed.
Publication date: Feb. 18, 2019
Revised: Oct. 9, 2019
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