Ants are annoying at picnics, but at least they don't sting or dive bomb you.
Hornets and yellowjackets are responsible for most of the "stinging" that takes place in Utah, says Jerry Goodspeed, Utah State University Extension horticulturist.
"They are social insects that live in a nest or colony. The colony consists of a queen with lots of workers. The nests are made of a papery substance and can be located almost anywhere--including roof eaves, fences, trees or any other nook they can find around your home."
He says some yellowjackets also nest in the ground. They can take up residence in small holes, old rodent nests, or under rocks or other old debris.
"These social hornets and yellowjackets can be highly aggressive and should be treated with care. Many hornets and yellowjackets are scavengers, feeding on dead insects, garbage, and carrion. However, late in the season they get a hankering for something a little more sweet such as soft drinks, watermelon, cantaloupe and cake. This is when they become major pests," Goodspeed says.
Controlling these pests who have built colonies next to a living area is easier than swatting them away at a picnic, he explains. First, locate the nest by following the insects as they head away from the water or food sources. Look for entrances in old trees, under eaves or around other wooden structures. Next, choose your weapon.
"Though there are many sprays on the market that kill hornets and yellowjackets, most contain a pyrethroid for a quick kill. They usually also have a propellant that sprays up to 20 feet. Using this type of pesticide allows you to remain far enough away from the nest that I can run if necessary," Goodspeed says.
"Be very careful when destroying hornet and yellowjacket nests," he cautions. "They will attack to defend their colony from danger, and their sting is very painful. Also for your own safety, only use products that are registered for use on yellowjackets and hornets, and be certain to follow all label directions."
Spray the nest at dusk, after the sun has set, he says. The insects in the colony are not as active at that time. Soak the nest, then come back later and soak it again. After the colony is dead, destroy the nest. Seal the entrance off with soil, mud, or just cave it in on itself to keep the pesticide and pests in the nest. If the colony is not a bother now, leave it until winter and destroy it then. The first heavy freeze generally kills the colony.
For more information, contact your local USU County Extension office.
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Issued in furtherance of Cooperative Extension work, Acts of May 9 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Robert L. Gilliland, Vice-President and Director, Cooperative Extension Service, Utah State University, Logan, Utah. (EP/09-98/DF)