Washington State University Extension

Garden Tips


GARDEN TIPS – written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written July 9, 2015


I have several colleagues who are entomologists. They are quick to teach novices like me that all bugs are insects, but all insects are not bugs. “True” bugs belong to the order of insects called Hemiptera and have several characteristics in common. One easily recognizable shared characteristic is a shield-shaped back that is created by their folded front wings. This also creates a triangle shape or “X” pattern on their backs.

Another common characteristic is their highly modified mouth or “proboscis.” It is a long nonretractable hardened tube or “beak” that allows them pierce plant parts and suck out plant or animal fluids. Plant bugs feed on a variety of plant tissues, but seed bugs are a specialized group of plant bugs that feed on the seeds of plants, enabled by their exceptionally long proboscises.

Seed bugs are not a concern in our yards, gardens and homes because they only feed on the seeds of plants. They do not attack humans and do not damage plants. However, they do become bothersome when their numbers become exceptionally large or when they migrate into homes in search of an overwintering spot in the fall or sometimes during the summer for protection from the heat.

Boxelder bugs are a well known seed bug that are often a major annoyance in our area. With their ½ inch long black body, black legs, and bright orange-red markings and “V” on their back, they are easy to identify. While they will sometimes feed on other trees and shrubs, they primarily attack the seeds of boxelder and other types of maple.

New on the local scene is a much smaller, nondescript seed bug, the elm seed bug (ESB). It is brown and about 1/3 inch long. If you look very closely (it is small) you can see lighter colored bands around the edge of the wings and a small black triangle on its shield-like back.

With greater magnification, on the underside of an ESB’s body you would note a long beak at least 1/3 the length of the body. This beak allows it to feed on its primary source of food, elm seeds. They certainly can find plenty of food in our region with the large number of invasive Siberian elms (Ulmus pumila) that produce copious seeds.

The ESB was just discovered in our area last fall when Dr. Mike Bush, WSU Extension Entomologist, confirmed its identity. The ESB is considered an exotic invasive pest and was first discovered in the U.S. in 2012 in Idaho. This summer it is being noted in large numbers here.

Pesticides are of little value in controlling ESBs and boxelder bugs in and around the home, but a perimeter spray application of pesticide may help decrease the population. Extension experts, like Bush, recommend pest-proofing your home by caulking cracks, plugging potential points of entry, and repairing screens instead of using pesticides. Also, cover outdoor vents to the home with mesh screening that allows for air movement but is fine enough to keep the bugs out.

Both these bugs have an unpleasant stinky odor that is released when crushed. This odor can “stink” up an indoor vacuum, so use a shop-vac inside and outside the home when vacuuming them up. Before starting, add some soapy water to the shop-vac canister to drown the bugs as they are sucked up and empty it immediately when you are done.

So, what is bugging you?

Garden Tips, WSU Extension, Benton County, 5600-E West Canal Drive, Kennewick, WA 99336-1387, 509-735-3551, Contact Us

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