Borers Killing Weeping Willows in Bradford County, NY

Symptoms Match Borer Attack

Sap oozing from multiple trunk points on weeping willows, with progressive decline over years, is classic for wood-boring insects (likely Cryptorhynchus lapathi, the poplar-and-willow borer). Corkscrew willows may be less preferred or not yet attacked.

Treatment

Spray trunks thoroughly with Onyx (bifenthrin) or Merit (imidacloprid) in spring when adults emerge. Wet bark to runoff, reaching as high as possible. Repeat in 4–6 weeks if sap flow continues. These insecticides kill larvae inside the trunk and stop further sap loss.

Cultural Support

• Water deeply during drought (1 inch/week).
• Fertilize lightly in spring with 10-10-10.
• Remove and destroy severely infested trees to reduce local beetle population.