Yellow Jackets

Labor Day often signals the end of the summer is near and so many insects are also beginning to wind down their activity. Yellow jacket colonies likely peaked back in late July or early August but they are still quite active and even aggressive in foraging for food.  So, while people are outdoors celebrating this weekend at parks, the beach or just in their own backyard, more than just their invited guests will be waiting for hot dogs, burgers and other items come off the grill.  The inclination is swat the unwanted visitors are they try to taste what sitting on our plates.  That can trigger an aggressive response by the yellow jackets.  Another piece of advice to give people - drink from cups rather than cans.   While we're busy sitting at picnic tables talking, we may not notice a yellow jacket sipping soda from the top of the can or crawling inside to investigate this sugar (or beer) gold mine.  Pour the beverage into a cup.

Trash and recycle receptacles will also be wasp magnets and can also pose a problem in parks, athletic fields and other recreation areas and they need to be emptied before the overflow with trash or beverage bottles/cans.  A lot of people try those yellow jacket traps that are sold are hardware stores.  We still haven't seen data that shows that they are effective.  If yellow jacket nests can be find, treating them with a Wasp & Hornet spray is the best choice.  Use a product that propels the chemical 10+ feet so you have a running head-start when the wasps start streaming out of the nest.  Some of these products are foams which help envelope the opening to the nest.   I would suggest treating late in the evening because it's unlikely that you'll kill all of the wasps and the survivors may return in search of their now-unusable home.  Also, discourage people from using home remedies such as gasoline.  While it may be viewed as entertaining, it's obviously hazardous and environmentally unsound.  Some people place bowls or rocks over the opening figuring that this is a "low impact" alternative to chemicals.  However, I have reservations about this approach particularly if there are "inquiring little minds" that might investigate this situation and move the object with the obvious unintended consequences.   Another technique some people try is to pour boiling water down into the hole.  That may seem "safer" than a pesticide but consider that you have to carry the water over to the nest and pour it down the opening and hope some of the occupants don't emerge to "encourage" you to go elsewhere.    Yellow jackets are actually quite valuable as predators and so if the nest doesn't pose a health hazard to you or family family members or friends, "Let it be"....

Michael Waldvogel, PhD
Extension Assoc. Professor & Specialist, Structural & Industrial Pests
North Carolina State University
Dept. of Entomology, Box 7613, 100 Derieux Place
Raleigh, NC USA 27695-7613