Pine root collar weevil

Hylobius radicis (Buchanan) (Coleoptera: Curculionidae)

Orientation to pest

The pine root collar weevil, Hylobius radicis (Buchanan), is native to eastern North America, where it is damaging in Scots pine (Pinus sylvestris L.) Christmas tree farms and in red pine (Pinus resinosa Sol. ex Aiton) plantations, but not natural forests. Eggs are laid in the root collar zone of healthy trees. Larval feeding may kill young trees or badly stress older trees. That stress can predispose mature trees to lethal attacks by bark beetles. This weevil is associated with several fungi linked to red pine decline. Damage may be reduced in a young stands before canopy closure by pruning away lower branches and removing litter and soil around the base of trunks to reduce weevil oviposition.

Hosts commonly attacked

The most frequently affected species is Scots pine (P. sylvestris), followed by red pine (P. resinosa), when grown in plantation.

Distribution

The pine root collar weevil is found from Newfoundland in Canada, south to Virginia and west to Minnesota and Manitoba.

Images of pine root collar weevil

Jennifer C. Giron Duque, University of Puerto Rico, Bugwood.org 768x512 / 1536x1024	James B. Hanson, USDA Forest Service, Bugwood.org 768x512 / 1536x1024	Steven Katovich, USDA Forest Service, Bugwood.org 768x512 / 1536x1024
Figure 1. Adult of the pine root collar weevil, Hylobius	Figure 2. Larva of pine root collar weevil dissected out of wood	Figure 3. Damage of pine root collar weevil in a mixed red and Scots pine stand

Important biological control agents related to this pest species

Very few natural enemies have been recorded attacking pine collar weevil, the main ones being the braconids Bracon radicis Shenefelt and Miller and Microctonus pachylobi Muesebeck.

Web links for information on pine root collar weevil

• BugwoodWiki Article | wiki.bugwood.org

Articles

• Wilson, L. F. and I. Millers. 1983. Pine root collar weevil - its ecology and management. Technical Bulletin No. 1675, United States Department of Agriculture, Washington, DC. 34 pp.
• Klepzig, K. D., K. F. Raffa, and E. B. Smalley. 1991. Association of an insect-fungal complex with red pine decline in Wisconsin. Forest Science 37(4): 1119-1139.
• Rieske, L. K. and K. F. Raffa. 1993. Potential use of baited pitfall traps in monitoring pine root weevil (Hylobius pales, H. radicis, and Pachylobius picivorus) populations and infestation levels. Journal of Economic Entomology 86: 475-485.