Stinging Insects Could Pose Autumn Risk

Date:  Oct. 7, 1997
Editor: D'Lyn Ford  (505) 646-6528, dlford@nmsu.edu

LAS CRUCES -- Stinging insects like wasps, yellowjackets and hornets are more active and aggressive in early fall, a New Mexico State University entomologist said.

"If you wait just a few more weeks, cold temperatures will take care of the problem for you," said Bob Cain with NMSU's Cooperative Extension Service. Until then, he advised being aware of and cautious around the stinging insects.

Common sense is the best method of dealing with these insects, Cain said. Most wasps are actually beneficial insects, and capture many pest insects to feed their young. If nests are not in high-traffic areas where they are likely to be disturbed or stumbled upon, simply avoid the areas.

Loud noises, including those made by power tools, can upset the insects. Be sure not to bump into nests, because the insects may become agitated. Multiple stings are not unusual.

If the wasps are aggressive and removal is necessary, it may be a good idea to get assistance from a pest control company or beekeeper.

If you decide to remove the problem wasps yourself, cover your body completely with heavy material to protect yourself from both the wasps and the insecticide. Late evening, when the wasps are less active, is the best time to treat the nests. "Work very carefully, because any disturbance of the wasps can cause a mass attack," Cain said.

Chemical controls should be applied from a distance using an aerosol or pressurized garden sprayer. Commercial wasp and hornet aerosol sprays that contain a pyrethroid insecticide flow out of the can in a heavy stream, which allows you to stand up to 20 feet away from the nest. Using a fogger is another way to apply pesticide. When using any pesticide, always follow label instructions and precautions.

"Sometimes a spray will only act as a repellant, driving the insects back into the nest long enough for you to tear it down," Cain said. After nests are torn down, they should be placed in a heavy plastic bag and treated with a lethal dose of pesticide.

Non-chemical control also can be used for stinging insects, Cain said. One alternative way of controlling yellowjackets near picnics or restaurants is to hang a piece of fish or meat over a large-mouth gallon jar of soapy water. When the yellowjackets leave the hanging bait, they often drop a short distance before flying and fall into the water.