Invasive Species Brown Marmorated Stink Bug Threatens US Food Crops


Photo by: http://www.bugwood.org/

According to researchers at Penn State University, the Brown Marmorated Stink Bug, Halyomorpha, halys, was first collected and positively identified in September of 1998, in Allentown, PA.  Since then it has made its odious presence known throughout the Mid-Atlantic and various other states, quickly expanding its range, from the East Coast to the west.  This little, brown stink bug, with sucking mouth parts, does not bite and is harmless to humans.  However, when disturbed or crushed it emits a foul substance that most describe as smelling like dirty socks or as being skunk-like.  A few have described it as smelling like cilantro.  Though only recently established in Oregon and identified in California, this troublesome Asian invader has been wreaking havoc in homes and orchards in the Eastern US for the last few years.  In its native Asian range, Halyomorpha is kept in check by a parasitic wasp, but in North America its numbers are allowed to increase, unchecked, because it has no natural enemies here, except domestic chickens.

Unfortunately, American pest experts are still behind the curve when itcomes to developing methods to effectively gain control.  Current agricultural pesticides are very effective against the nymphs but control of the adults is more difficult.  Populations rebound very quickly and the adults, being strong fliers, can move in rapidly from untreated areas.  Since modern agricultural insecticides have little or no residual, protective properties, those areas will likely require re-treatment to gain control of each new wave of invaders.  This can become a repetitive and expensive process.  Additionally, any insect that reproduces as rapidly as this one does has great potential for developing resistance to the pesticides being used against it.  2010 has been a banner year for these, shield-shaped, true bugs.  Although they normally produce just one generation per year in temperate climates, this year, because of the northeast’s unusually warm spring weather, they have produced up to three, in some locations, leading to a population explosion.  Homeowners all over the northeast are reporting massive numbers of stink bugs on the exterior walls of their homes, sometimes in the thousands, with dozens making their way into the interiors.  The reason for this behavior is that the adults are looking for protected locations in which they can over-winter.

Image by: The Bugwood Network

It’s bad enough that these creatures have become such nuisances to homeowners, but their impact on food crops is becoming a topic of serious concern for home gardeners, farmers, orchardists and agricultural experts.  Halyomorpha, halys feeds on both foliage and fruit of important crops.  Raspberry, blackberry, apple, pear, peach, tomato, pepper, soybean and corn are just a few of the crops that have been hit. This bug actually feeds on a much wider selection of food producing and ornamental plants.  Almost no crops are immune.  Its feeding causes deformation, discoloration and dry, cork-like areas in the fruit of host plants.  This damage on fresh produce makes it unmarketable in retail outlets and it must be downgraded and sold for processing at a reduced price.  This reduction may be as much as 60 percent, resulting in huge losses.  Some growers in the Northeastern US, where this pest is most established, have experienced crop losses in excess of 50 percent. The recent discovery of this pest in California is alarming because of its potential impact on that state’s enormous and important agricultural industry.  In California’s warm climate, Halyomorpha, halys has the potential for explosive population increases.  Some parts of the state have such mild winters that the pests may be able to reproduce year-round. There is a very real possibility for millions of dollars in damage to the United States  food supply, a large percentage of which is grown in California’s central valley.  Unless effective monitoring methods, preventive measures and controls are developed soon, this infestation could result in serious shortages, higher prices, and more dependence on foreign imports.

According to an article, By Jim Hook, Senior writer at Public Opinion Online, entitled  Congress: Swift action on stink bug,  U.S. Reps. Roscoe Bartlett and Todd Platts have asked the U.S. Department of Agriculture to quickly reclassify the stink bug, Halyomorpha halys as a regulated insect.   According to Mr. Hook’s article, Under Section 18 of the Federal Fungicide Insecticide and Rodenticide Act, EPA can allow an unregistered use of a pesticide for a limited time, if EPA determines that an emergency condition exists.  This would allow the use of broad spectrum insecticides, not specifically registered for use against this insect, in an attempt at gaining control, before we have a plague of biblical proportions.  If congress takes this action it will be welcome news indeed.