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Odd bugs invade summer gardens

August 03, 2010|By ANNETTE IPSAN

Some very curious insects are landing in area gardens, causing some worries among locals. With War of the Worlds overtones, callers are expressing concerns about mutant bugs invading their backyards.

Not to worry. The insects we are seeing now are large and scary-looking, but not bad at all. One of the more interesting aspects of being the resident "bug lady" is discovering that the nastier a bug looks, the more benign it is.

Two insects are causing my phone to ring off the hook: June beetles and cicada killer wasps.

Cicada killer wasps look like yellow jackets on steroids. They are two inches long, mostly black with bold yellow marks on their fannies. As their name implies, they kill cicadas. Cicadas can damage trees by laying eggs under the soft bark of new growth. These wasps keep them in check.

Most people first notice cicada killer wasps because they are big and buzzing low over their yards. These are the males guarding their nests or hunting for lady friends. Their nests are index-finger-sized holes in the ground, which the females dig, leaving telltale piles of excavated soil.


Into these holes they stuff paralyzed cicadas on which the female wasp lays her eggs. The wasp youngsters eat the cicada when they hatch, a fact that elicits "cool" or "ick" comments from kids at my bug talks. As adults, cicada killer wasps feed on flower nectar.

Fine and good, you say, but do they sting? Almost never. The males don't even have stingers, and the females usually only sting if you sit or step on them. They are all about the cicadas, not nabbing you. And they are around only a few weeks.

Cicada killer wasps drill their nests into bare or sandy soil or patchy grass. Discourage them by beefing up your lawn. They also like dry soil, so a sprinkler might get them to move on. As a last resort, sprinkle insecticidal dust into their holes at night. Again, these are good guys, so let them be if you can.

June beetles are the other insects that trouble people this time of year. These shiny green beetles look like Japanese beetles on a serious workout plan. Up to a half-inch wide and almost an inch long, they sometimes hover and fly over lawns in large numbers, buzzing loudly. Very disconcerting.

But again, June beetles are harmless. They feed on thin-skinned fruit and plant sap. They fly badly, crashing into our shins and screens like clowns. They can't bite and are around for only a few weeks. What's not to love?

These green comedians do have a white grub form that can cause mild damage to lawns. As with its adult beetle form, it's a big boy. The size of your pinky finger, the June beetle larva burrows into soil, leaving a hole mounded with soil. It feeds gently on roots, so control is seldom needed.

There is no mistaking the June beetle grub for other grubs. In addition to being huge, it has the charming habit of walking on its back. Yep, those little legs paddle in the air while it wriggles along on its back. Again, this is a big hit with the kids I talk to about bugs. Guaranteed giggles.

See? Those nasty-looking bugs aren't bad guys at all. In fact, only about 10 percent of all the insects out there are harmful.

Most are good guys, helping to keep the bad guys in check and preserving the natural ecological balance in our backyards. Three cheers for good bugs.

Annette Ipsan is the Extension educator for horticulture and the Master Gardener program in Washington County for the University of Maryland Extension. She can be reached weekdays by telephone at 301-791-1604, or by e-mail at">aipsan@umd.edumail at

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