When Marietta homeowner Ted Persky started finding dirt mounds in his yard, he contacted an exterminator. After finding out they were not anthills but wasp mounds, he and a neighbor decided to get more information.

Will Hudson, a Cooperative Extension entomologist at the University of Georgia Tifton campus, offers advice to people who've found a recent invasion of mounds in their yards.

"Most Georgians are familiar with yellow jackets and bumblebees," Hudson said. "But many wasps and bees that nest in the ground are solitary insects."

Many of Persky's mounds were close together. Hudson said this is an "aggregation," or a community of the solitary insects. They prefer to be close together, but they don't nest in the same burrow.

Persky just bought his house last August, and no other neighbors have noticed the mounds before this year.

Single mothers

Hudson said that after the female wasp mates, she digs out a burrow, lays an egg and lives alone for the rest of her life. The burrowing process lasts only a few weeks in the spring. For the rest of the year, the wasp or bee is inside her nest.

The wasps aren't dangerous or aggressive and should be left alone, he said. Social insects, such as paper wasps, may attack because it doesn't matter if a worker dies, as long as the queen stays alive. This isn't so for a solitary female wasp. She can no longer reproduce if she tries to protect her nest and dies doing so.

"I've walked through these aggregations lots of times, and none has even tried to scare me," said Hudson. "In most cases, you would almost have to catch one in your hand to get it to sting you."

It's safe for animals and children to be around the mounds at this time of the year.

Good guys

You may not think such insects would be beneficial in any way, but Hudson emphasizes their positive points. He urges people not to kill them.

"Some bees can be important pollinators, and there can be serious implications for flowers and fruit if these insects are exterminated," he said.

If you want to stop these wasps or bees from burrowing in the first place, Hudson has a tip.

"Most of them don't like areas with solid turf cover," he said.

The insects wind up in shaded areas where the grass is thin and they can get into the soil surface easily. A thick, healthy lawn will prevent the mounds.

"Most people don't think of prevention but how to get rid of them," Hudson said.

If you do decide to get rid of them, the wasps and bees are sensitive to easily available insecticides at local garden shops. But Hudson said the adults are only active for a few weeks, and then "you have no idea they're there."

(Kristen Plank is a student writer with the University of Georgia College of Agricultural and Environmental Sciences.)