Tim Gibb, Entomology Department
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(Photo Courtesy of Tim Gibb)
Yellow jackets, those pesky, yellow, wasps that many Hoosiers refer to as 'bees' or 'yellow bees' and that frequent picnic grounds every fall, are out in force. They are searching for sweets and proteins right now, which is why they're often found around trash cans, at picnics and sporting events, nearly anywhere food is exposed.
Each year in Indiana we receive reports of people being stung in the mouth or the throat area when they inadvertently swallow a yellow jacket that has entered their soft drink can or hidden itself in food about to be consumed. Stings are always very painful and can be an extremely serious health threat if multiple stings occur or if the victim happens to be hyper-allergic to the venom.
A systemic reaction, or one that causes more than just localized swelling, can be life-threatening, and the victim should go to an emergency room at once. Symptoms include hives, swelling at other parts of the body, difficulty breathing, loss of consciousness, and drop in blood pressure. These can accelerate to the point where the victim goes into shock.
In the case of multiple stings, a victim might experience nausea, vomiting, lowered blood pressure, and a shock-like state may also occur. It's also probably wise to seek medical assistance for any stings in the mouth or throat, because swelling could close the victim's airway.
Just for a typical sting, however, it's not usually necessary to see a physician. Local swelling at the site of the sting, together with some burning pain is expected. Time, along with a cold compress to help reduce swelling and an antihistamine, such as Benadryl, to combat itching, is the only treatment.
Avoidance is key to not getting stung. It may seem that yellow jackets are everywhere during late summer and early fall because colonies are at maximum size, somewhere between1,000 to 4,000 workers.
Avoid them by making food inaccessible to them. Simply keeping foods covered and away from people as much as possible will help prevent yellow jacket attraction. This seems like a simple step, but it goes a long way in decreasing the number of stings each year.
Increased attention to sanitation will also help. Keeping garbage receptacles clean and closed when possible, eliminating potential food sources, and keeping doors and windows closed will decrease yellow jacket encounters.
Stay away from yellow jacket nests. Like many social insects, yellow jackets defend theri nest very aggressively when it is threatened. (When wasps are away from their nests, they're not nearly as aggressive). If a nest is encountered or bumped into by some unsuspecting person, serious consequences are usually in store. Common sense and being on the look-out for nests will prevent a lot of misery. Look for gray paper nests hanging on the sides of buildings or localized heavy traffic of wasps moving into or out of an opening.
Two species of yellow jackets are most common in Indiana. The eastern yellow jacket nests in the ground, and the German yellow jacket nests inside structures.
If a nest is found in an area where people might come in contact with it, call professional pest control to deal with it. If the nest is encountered away from where people might accidentally contact the yellow jackets, leave them be. Remember that even though they can be dangerous, yellow jackets are infact are beneficial insects. They feed on other insect pests and also help remove garbage from the environment. For these reasons, nests away from public areas should be left alone.
Also remember that nests are never re-used a second year. If a nest can be left until late fall, the queens will leave and the rest of the wasps will naturally die off. That particular nest will not be used again. If you think about it, the nest has been in place for several months already and if nobody has gotten stung until now, chances of leaving it for another few weeks without a sting are good.
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Last updated: 9 October 2001/tlm.
The Plant & Pest Diagnostic Laboratory at Purdue University.