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Black Vine Weevil - Otiorhynchus sulcatus
  www.ohionline.osu.edu  Helen Atthowe - Missoula County Extension
 HOSTS: Strawberries,
clematis, euonymus,
lilac,
rhododendron. DESCRIPTION:
Adults
are dark-gray or black snout beetles about 1/3 inch long with wing
covers marked with gold flecking; larvae are weevils, greater than 1/4
inch long, dark in color and thick bodied. LIFE
CYCLE: Root
weevils overwinter in the larval stage around the roots of the host
plant. Adults emerge during late spring and early summer and feed for
about two weeks before laying eggs. They feed at night and move to
debris around the base of the plants during the day. Eggs are laid
throughout the summer in soil cracks around the host plant. Larvae feed
on roots during the summer and fall; peak feeding occurs the following
spring. Larvae pupate in the soil surrounding the host plant. There is
one generation per year. Adults often envade houses in early summer. CONTROLS:Biological: Parasitic nematodes (Steinernema carpocapsae) applied to black plastic mulched strawberries in the drip irrigation system twice, once in the spring and again in late summer, reduced black vine weevil by 50%. Parasitic nematodes (Heterorhabditis bacteriophora) applied at 5,000/pot effectively controlled black vine weevil in Maryland. H. bacteriophora efficacy is reduced at soil temperatures below 68° F. Late summer application is recommended in western Montana. Keep soil moist after application. These nematodes do better in pots if sub-irrigated rather than overhead-irrigated. |
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