Hylobius warreni (Curculionidae)
Warren's collar weevil
||8-11 mm in length, dull black and clothed with fine grey
scales between the patches of white. Notice the snout which is characteristic
of this family.
||Larvae are white, legless, curled and practically
indistinguishable from other larvae in this family. When larva is feeding
around the root collar, dirt and shredded bark are packed together with resin
from the tree to make a protective "tunnel". Trees less than 6 cm in diameter
can be girdled.
||Larvae which live for 2 years feed in the root collar area,
often causing the cambium to be girdled. The adults live and lay eggs for
up to 4 years, are flightless and feed upon the bark of small roots and twigs
and on the needles of its hosts. Lodgepole pine can have chronic weevil
infestations around the root collar area throughout the rotation. Trees less
than 6 cm diameter can be girdled and killed. Otherwise, larger diameter
trees seem to survive one or two feeding larvae.
In B.C. the main host is
pine, but other recorded hosts include other
Mortality can result from root collar girdling as well as reductions in growth.
Trees from 6-8 year sold to maturity are attacked. Larval damage also provides
an avenue for infection by root-rotting fungi. This weevil may seriously
hamper the establishment of pine plantations.
References and Links:
EAG: 554; FC: 326.
See Warren's Root Collar Weevil Stand Establishment Decision Aid.