NC State Extension Publications

Description and Biology

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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 weevil

Pales weevils are very dark and usually have gray or orange spots.

This pales weevil has orange spots

This pales weevil has orange spots.

Pales weevils are attracted to freshly cut pine stumps.

Pales weevils are attracted to freshly cut pine stumps.

Pales weevil grubs

Pales weevil grubs are legless and white with brown heads.

Host Plants

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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.

Pales weevils chew away the bark

Pales weevils chew away the bark of seedlings and twig.

This flagging was caused by pales weevils girdling twigs.

This flagging was caused by pales weevils girdling twigs.

Pales weevils readily breed in fresh stumps.

Pales weevils readily breed in fresh stumps.

Residential Recommendations

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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.

Other Resources

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For assistance with a specific problem, contact your local Cooperative Extension Center.

This Factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology & Plant Pathology

Publication date: Feb. 18, 2019
Revised: Oct. 9, 2019

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