Stinging Insects this Fall
Kalamazoo, Mich.- Each fall bees, hornets, and wasps may exhibit aggressive behavior when disturbed by humans whether their nests are in trees, on patios and decks, or in the ground.
As temperatures cool in September, yellowjacket numbers peak just as their food supply begins to decline. They scavenge more aggressively, searching for food in trash bins and near picnics. When disturbed, yellowjackets can sting repeatedly; their stingers are not barbed nor lost after stinging.
Other aggressive stinging insects include paper wasps and hornets. These stinging insects live in colonies and don’t return to the same place each year. Paper nests are large, grayish-brown with an inverted pear-shape with the entrance at the bottom and usually located away from possible rain damage.
Bees, hornets, and wasps are BENEFICIAL INSECTS and play an important part in the pollination process in agricultural production and also serve as valuable predators in controlling harmful insects. Whenever possible, try to live peacefully beside the bees, wasps, and hornets in your neighborhood. Stinging behavior is a defensive behavior in response to being disturbed. Not all bees, hornets, or wasps will respond negatively when disturbed. There are no Africanized bee colonies in Michigan.
Prevention is your best choice to avoid attracting bees and wasps in the fall:
- Remove sources of attraction. Locate trash areas as far from humans as possible. Keep lids to garbage cans closed tightly.
- For above-ground nests, remove and discard the nest or caulk over potential nest entrances in permanent structures (such as stone walls, house foundations, window sills) to prevent usage next year (wait until all the bees or wasps have departed).
- In spring, caulk over holes in nesting structures attractive to bees, hornets, or wasps such as children’s play equipment. Try to control nests earlier in the season if the area they nests in has proved to be a problem in the fall.
Many times, trying to destroy in-ground nests or tunnels may be a greater risk to human health than consciously tolerating the bees and wasps by simply avoiding them during the fall.
However, when it is not possible to avoid the ground-nesting bees and wasps they may be controlled following these steps:
- During the daylight hours, observe the undesired bees or wasps to locate their nest entrances.
- After dark and, approach the nest with caution. Protect against possible stings by wearing long sleeves and long pants. Cover any light source with red cellophane (insects cannot see red light) or locate the light where it will not attract the bees or wasps.
- Treat the nest tunnels with a dusting of a product containing carbaryl as the active ingredient. Note that the actual underground nest may be several feet from the nest entrances. Repeat applications may be required.
- Other insecticide sprays may be available and useful but dusts are advantageous since they do not soak into the soil. Always read and follow the label directory and safety precautions. Repeat applications may be necessary.
Researched and written by Babette Schmitt, Master Gardner in training.
To obtain more information about Consumer Horticulture issues and the Master Gardener Volunteer Program, call Linda Whitlock, Consumer Horticulture Educator at the Kalamazoo County MSU Extension Office at (269) 383-8815 or email her at whitlo13@msu.edu
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MSU Extension is an Affirmative-Action Equal-Opportunity Institution. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, marital status, or family status.
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