Scavenging yellow jackets may be pining after sap

Posted on Jan 15 2015 in Backyard

Yellow JacketsI have small evergreen trees planted in my yard. They are the small, slow growing type. They are around 8 years old. Every fall, yellow jackets start swarming around them and crawling in and out of the inside of the trees. They don’t seem to hurt the trees, but it looks as if the yellow jackets are trying to find something — acting like a honeybee on a flower.

But these trees have no flowers. They don’t bother us as long as we don’t get to close. Could you tell me why this is happening?

— Cindy Kellams, Shoals, Ind.

Our Purdue entomologists advise that yellow jackets commonly scavenge for food in fall, and it is likely that they are attracted to tree resin or sap that has some sugar content.

Scavenging yellow jackets are less aggressive than those protecting a nest. And you are correct; they will not harm the trees and will generally not attack unless provoked. We commend you for aiming for a peaceful coexistence! More information can be found in the Purdue E-44 publication on Social Bees and Wasps.

B. Rosie Lerner is the Purdue Extension consumer horticulturist and a consumer of Tipmont REMC. Questions about gardening issues may be sent to: “Ask Rosie,” Electric Consumer, P.O. Box 24517, Indianapolis, IN 46224, or