Black vine weevil

Notched leaf margins on rhododendrons, yews, and other broadleaf evergreens are the calling card of black vine weevil adults feeding at night. The real damage happens underground, where white, C-shaped larvae devour roots from fall through spring. You will see plants wilting or declining despite adequate water, sometimes collapsing entirely when root systems are destroyed. This is one of the most damaging root-zone pests in Western Washington landscapes.

Apply entomopathogenic nematodes (Heterorhabditis bacteriophora) as a soil drench in September when larvae are small and soil temperatures are above 55 degrees. Sticky barriers around container rims trap flightless adults. Hand-pick adults at night with a flashlight. Avoid piling mulch against stems where adults hide during the day.