What’s bugging Inyo County?

The Agricultural Commissioner for Inyo and Mono Counties, Nathan Reade, sent out a press release a few weeks ago to explain why small black bugs which are about half and inch long, with black and orange or red markings, have suddenly appeared in large numbers around homes and businesses from Chalfant Valley to Pearsonville.  His office has been flooded with calls and complaints from residents concerned about the infestation of the Western Boxelder bug (scientific name, Boisea rubrolineata).

Although considered relatively harmless, boxelder bugs are primarily a nuisance because they enter homes and other buildings, often in large numbers. They do not sting or bite people as a rule, transmit any disease, and are essentially harmless to property unless, when abundant, they can stain light-colored surfaces such as walls, curtains, and other surfaces with their feces.

Harmless or not, Carl Olson (a.k.a., the “Bug Man”), the curator of The University of Arizona Entomology Department’s research insect collection, which has about one million specimens, said, “People have no tolerance. They think all bugs are bad. It’s the American way. If you don’t like something, kill it.”

Many of the calls to the Agricultural Commissioner’s office are residents looking to do just that—“Kill them!”

Unfortunately, it’s not that simple. Much like Steve Seagal in the 1990 movie “Hard to Kill,” just when you think that you’ve got a handle on your boxelder bug problem, it returns like the proverbial bad penny (much like the Seagal movie itself).

According to Reade, boxelder bugs usually feed on the leaves, flowers, and seedpods of the female or seedbearing box elder tree (Acer negundo), although they may also subsist on male box elder trees and occasionally occur on maple and ash trees. They may feed on the fruits of almond, apple, cherry, peach, pear, and plum trees, and on grapes, where their feeding punctures cause the fruit to become deformed. Large numbers of the bug usually occur only on female box elder trees.

The boxelder bug usually turns up during the spring or beginning of summer, usually in June or early-July after a mild winter, and then again in the latter part of the summer around August, says Reade.

“Pearsonville was buried in them two months ago,” he noted.

Finding where the bugs are hidden can be difficult. They can as easily come from your neighbor’s yard as your own or, given that they have wings and can fly, even from several blocks away.

According to the University of California Statewide Integrated Pest Management Program, in the fall, the adults seek overwintering places in dry, sheltered hollow tree trunks; under rocks, boards and other debris; in cracks and crevices in walls; in door and window casings; around building foundations; and inside houses.

On warm days during winter and early spring, boxelder bugs sometimes appear on light painted surfaces outdoors on the south and west sides of the house, resting in the sun.

You’ll be happy to know that they do little damage to ornamental trees. They do not injure people or pets, but when they come indoors, they can be annoying and may spot curtains, furnishings, and clothing with their excrement. Know that when crushed, they give off an offensive odor.

You will also be happy to know that at least that they do not breed indoors and if trapped in basements or houses, they will eventually die—although that may be small comfort knowing after enduring weeks of an infestation!

Insecticides are generally discouraged, and should never be used inside the home. Even if only used outside, chemicals can end up in creeks and groundwater. Many local pest control companies have advised callers that spraying does little to lessen the Boxelder bug problem and recommend that the best solution is to wash them off outside walls or on tree trunks using a forceful stream of water. Using insecticidal soap or a homemade solution of natural soap and water is recommended by several sources to kill the bug. (The dishwashing soap, Dawn, is often recommended.) Use a vacuum to pick up the dead insects.

You can also eliminate host trees. Since the box elder tree is the main source of food for the boxelder bug, removing the trees, especially the female or pod-bearing trees, is the most effective way of controlling the pest. Other types of trees include maple, ash, and liquidambar trees. Removing debris such as piles of rocks and leaves eliminates daytime hiding places said Reade.

To keep the bugs out of your house, make sure your window screens are in good repair and anywhere bugs might enter the house or building through cracks or beneath doors and windows are sealed.

Expect another infestation around August, warned County Agricultural Commissioner Reade. About the only thing that really keeps the bugs under control are cold winters, which kills off many of the boxelder bug and explains why this has not been as big a problem in Mono County as it has been in Inyo County.

For more information, please contact the Inyo Mono Agricultural Commissioner’s Office at (760) 873-7860 or visit their website at www.inyomonoagriculture.com.