University of Vermont Extension 
Department of Plant and Soil Science

Summer News Article
line

THE LATEST BAD BUG
 
Dr. Leonard Perry, Extension Professor
University of Vermont

As if we didn’t have enough serious invasive introduced (exotic) pests to watch for, such as the emerald ash borer and Asian long-horned beetle, we now have another Asian import—the brown marmorated stink bug.  In the U.S. now for over a decade, it has spread to 32 states.  First detection in Vermont was this year. It feeds on many fruits, vegetables, and farm crops, either making them inedible or unsalable.  This stink bug is a nuisance in homes as well.

First detected in eastern Pennsylvania in the mid 1990’s, this true bug likely arrived (as do many other exotic pests) in packing material from Asia.  Even in its native China, Korea, Japan, and Taiwan it is an agricultural pest.  This pest has caused widespread damage to apples and peaches in mid-Atlantic states, and could cause similar damage in other states.  The apples end up with many brown spots called “cat facing,” that makes them unmarketable. Other fruit crops it damages with dead spots include other stone fruits like cherries, pear, grapes, and brambles.  Host vegetable crops include corn, tomatoes, beans, cucumbers, eggplants, and peppers among others. 

Many ornamental plants also are susceptible to this stink bug feeding including both trees and shrubs, ending up with dead patches on leaves.  These bugs may feed on the main trunk and side branches for the sap.  If you see wasps feeding on sap, look for the bugs. Even flowers aren’t immune, with feeding reported on zinnias, snapdragon, and sunflowers among others.

The adults emerge in late spring, mating and laying eggs in summer.  Look on the undersides of leaves for clusters of 20 to 30 light green, barrel-shaped eggs.  Small black and red nymphs hatch, and go through five stages before turning into adults.  Adults, like other true bugs, feed on plant sap with a beak consisting of piercing-sucking mouthparts resembling straws.   In early fall the adults search for overwintering sites such as in buildings and other protected sites.

The adults are about 2/3-inch long, patterned in shades of brown.  Similar to other stink bugs, their shield shape (wider at the rear) is about as wide as long.  Their differences from other stinkbugs may not be obvious to the untrained eye so, to make sure, consult your state university plant diagnostic clinic.  These can be found online, including those for Northeast states (www.nepdn.org).  A main difference from the common native stink bug is on the antennae.  Look for alternating light and dark bands on antennae of this exotic pest.  More descriptions and photos can be found online, including from Penn State University (ento.psu.edu).

This stink bug is attracted to warm home exteriors in the fall, and can enter through cracks and openings.  Inside, these bugs don’t harm humans, but can be a nuisance flying about similar to Asian lady beetles and cluster flies. When squashed or sucked into a vacuum, the foul odor released makes their name obvious.  This chemical may cause a slight allergic skin reaction in some.  To avoid this odor, vacuum a pleasant smell such as potpourri (available inexpensively at many craft stores) first, or use a shop vac already with some soapy water.

There are some pesticides that can control this pest, but they are generally not recommended in homes and gardens.  Pesticides in homes can be dangerous if misused, and spraying around cracks is temporary and ineffective overall.  Best is to seal any gaps or cracks where they can enter and vacuum up any seen. 

Pesticides for stink bugs in gardens also kill good predator insects, if not pollinators too, resulting in outbreaks of other pests such as spider mites.  By solving one problem you merely create another.  Best is to inspect plants for the bugs often and regularly, knocking them off into soapy water.  Researchers are working on biological controls that will kill this pest and not predator insects and other native stink bugs that don’t cause problems.  Being an introduced pest, no natural biological controls are present in infested areas.
           
Although this bug can fly, and does so moving from crop to crop through the season, it spreads longer distances mainly through hitchhiking on materials moved by humans.  If you’re visiting, or moving from, an area with known infestations, make sure to watch for these bad bugs.  Check vehicles, campers, packing materials, or other objects that you’re transporting from outdoors during the growing season, and from indoors during other times of year.


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