Ground wasps can be pesky

This has been a summer to remember. First, it was the lengthy stretch of hot and humid days, followed by thunderstorms that caused flooding in some areas.

As if the mosquitoes weren’t bad enough, a new pest has been spotted in and around the area: Cicada Killer Ground Wasps.

But despite being large and frightening in appearance, the ground wasps aren’t harmless for the most part.

And although it’s been circulating that the ground wasps were brought into the state to combat the cicadas, extension office and pest control entomologists have dismissed that rumor.

“That is incorrect,” said Dr. Colleen Cannon, who has a PhD in Entomology and has been employed with Plunkett’s Pest Control in Fridley for 15 years.

“Ground wasps are native to Minnesota and every state in the country.” “I’m not really sure why there are more ground wasps than usual. Ground wasps like sunny, sandy areas so it has nothing to do with all the rain we’ve had this summer.”

Several Minneota residents have reported seeing ground wasps burrowing in their lawn, while they were also observed in a sand pile at a construction site.

“There are many species of ground-nesting wasps,” said Jeff Hahn, an Entomologist with the University of Minnesota Extension Office.

“Cicada Killers are a common, native insect that are found throughout Minnesota. I doubt they just arrived to the area. They likely have always been there, but just not noticed before.” As the name suggests, Cicada Killer Wasps prey on cicadas. Even though Cicada Killers are considered ground-nesting wasps, they are actually solitary; meaning there are any actual nests. Instead, they burrow up to four-feet deep in the ground into which they dig up to 16 chambers to lay eggs and place a captured cicada. Once the young are hatched, they feast on the cicada. Often, though, they will return to the same area the next year. One of the reasons for the increase of ground wasps being seen this summer may be because of an increase of its prey.

“(Cicada Killers) have been predators of cicadas since long before there were any people here,’ said Jay Bruesch, Technical Advisor at Plunkett’s Pest Control for 36 years.

“We have seen an increase in their numbers recently; most likely due to the sheer number of Dog-Day Cicadas present this year. Dog-Day Cicadas live in the soil for three years prior to emerging and becoming an adult.”

“The reason for the increase in cicadas may have more to do with overall temperatures than the rain. This is purely speculation, but mild weather late in 2015 may have helped the nymphal cicadas to survive these past three years.”

Because ground wasps are fairly large, it’s assumed they are dangerous. But that is also a misconception about the insect that ranges in size from 1 to 1 1/2 inches. They can be identified by their stout body, black and reddish brown thorax, amber colored wings, reddish brown legs, and black abdomen with yellow bands.

“They do not defend the ground burrow as some wasps might defend their nest, such as yellow jackets or hornets,” said Bruesch.

“It’s possible to carry out normal activities around a lot of ground-nesting solitary wasps without getting stung.”

Female Cicada Killer Wasps have stingers, while males will aggressively guard a territory and challenge other males or even people, but they lack a stinger and are unable to harm us. “That female sting if part of the egg-laying apparatus,” said Dr. Cannon.

“They are fairly large and gentle, but you can walk through the area they are flying around and not get stung. I suppose if you sat on one, you would get stung. Even though the sting is painful, it’s not medically serious.”

“The chance of getting stung is very small,” said Hahn. “The females are very reluctant to sting, but can do so if they are directly threatened.”

“I’d advocate ignoring them until they go away on their own, which will be in several weeks. However, that can be challenging for some people to do considering how large the insects are.”

If the sight of these large flying insects is bothersome, there are some things a homeowner can try to get rid of them.

“If a resident wants to control Cicada Killers, each individual nest needs to be treated,” said Hahn.

“You can try soapy water, but I don’t think that will be consistently effective.”

“Ideally, a dust or granular insecticide labeled for lawns is needed for the most effective control.” For those not wishing to use insecticides on their lawn, Dr. Cannon suggests trying a lawn sprinkler.

“If you want to avoid the use of pesticides, run a sprinkler on the area for a few hours,” she said.

“This discourages nesting as the water gets into the tunnels and harms the young.” And to avoid the return of these types of wasps, there are ways to deter them.

“Exposed, sandy soils in sunny areas seem to be a favorite mating and burrow-making site,” said Bruesch.

“Installing mulch, turf grass, or landscaping trees may offer some relief in the future.”