Black vine weevil adults will emerge soon

The best time to apply an insecticide to kill black vine weevil adults is the first two weeks after they emerge.

Dave Smitley, Michigan State University Extension, Department of Entomology - June 3, 2011

MSU Extension’s Tom Dudek reported on Wednesday, June 2, that Michigan Department of Agriculture and Rural Development nursery inspectors in Ottawa County have found black vine weevil pupae and expect adults to emerge soon (Photo 1). Timing is critical for black vine weevil control in nurseries.

The best time to apply Talstar or another insecticide to kill black vine weevil adults is the first two weeks after they emerge. Soon after the adults emerge, they will begin feeding, leaving characteristic notches in the edges of leaves. Good control of adult weevils will prevent the development of larvae that feed on the roots and below-ground stem of yews and other nursery plants (Photo 2).

Black vine weevil larvae
Photos 1 and 2. Left, black vine weevil adult. Right, a group of over 20 larvae found around the roots of a container-grown spruce.

Dr. Smitley’s work is funded in part by MSU’s AgBioResearch.

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