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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Move over stink bugs, here comes the kudzu bug, Megacopta cribraria

 

Adult kudzu bugs are small, only about ¼ of an inch in length.

 

First it was bed bugs, then it was brown marmorated stink bugs, and guess what, now there is a new bug in town! The kudzu bug, a.k.a. bean plataspid, lablab bug, or globular stink bug, threatens to be an important pest of crops and unwelcome invader of homes. 

Kudzu engulfs surrounding trees and shrubs in landscapes.

This tale begins not with the bug itself, but with one of its favorite sources of food, kudzu, often called ‘the vine that ate the south’. This invasive plant was first introduced to the United States at the Centennial Exposition in Philadelphia in 1876. Selected for its ornamental value, it once adorned the Japanese House in Fairmount Park, PA. Its ability to fix nitrogen, tolerate drought, serve as forage for livestock, and reduce soil erosion made it a popular choice for planting during the Dust Bowl years and its range in the US expanded dramatically. Kudzu cares nothing about blue or red states, and it is now found coast to coast and border to border. 

In Asia kudzu serves as one of the favorite hosts for many species of insects including the nefarious kudzu bug and, until recently, careful inspections and lady luck barred entry of this insect to North America. This changed in 2009 when kudzu bug was discovered near Atlanta, Georgia.  How it arrived in the US is anyone’s guess, but like its cousin the brown marmorated stink bug, the kudzu bug is a good hitchhiker and it may have arrived as a stowaway in a cargo shipment from its aboriginal home in Asia. In just three years, the bug moved from Georgia to the nearby states of Alabama, Florida, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia. Earlier this month, Dr. Bill Lamp, at the University of Maryland, and the intrepid members of his laboratory discovered the bug in patches of kudzu in Anne Arundel, Calvert, Charles, Prince George’s, and St. Mary’s counties in Maryland. It has also been detected recently in Delaware. 

Nymphs and camera shy adults frequent the underside of leaves.

 

Nymphs of kudzu bugs are almost as hairy as the vines of kudzu on which they feed.

As a foodie fond of invasive kudzu, some might herald the arrival of the bug as a blessing, but this bug has a darker side. In addition to kudzu, one of Maryland’s most important crops, soybeans, is also on the menu. Soybean growers in infested states have already reported important losses associated with kudzu bug.  This critter has sucking mouthparts that, once inserted into the leaves and stems, rob the soybean of its nutritious sap. The removal of these vital fluids can significantly reduce yields. In addition to kudzu and soybeans, wisteria, a widely planted and naturalized ornamental plant, also serves as a competent source of food.

 

An adult kudzu bugs warms up its wings in preparation for flight.

Like its cousin the brown marmorated stink bug, kudzu bug is also a stinky home invader. Stinky, you bet! While collected kudzu bugs, I learned that it does not take much for these little guys to release their pungent defensive odor.  Dramatic pictures from southern states show sides of homes festooned with thousands of kudzu bugs seeking overwintering refuge in the autumn. In nature, winter refuge is usually provided by plant debris in the field or beneath loose bark of trees, however, where human-made structures adjoin soybean fields, prepare for an incursion. Does this sound familiar?  After passing the winter in protected locations, adults emerge in spring and move to soybeans, where they mate and deposit ranks of barrel shaped eggs on the undersides of leaves. The eggs hatch and hairy greenish-yellow nymphs feed on plant sap for several weeks before molting to the adult stage. These adults lay eggs and the cycle is repeated, and the ensuing adults are the ones that seek overwintering refuge in autumn.  Adding insult to injury, defensive secretions of kudzu bugs can stain fabric, walls, and skin, and may cause skin irritations including blisters in sensitive people. In this time of global change and the creation of a global biota, get ready for another visitor from afar, the stinky kudzu bug.  

To learn how to exclude invasive bugs from your home, including stink bugs and kudzu bugs, please watch the following video:

 

References

 

Bug of the Week thanks Alan Leslie and Bill Lamp for the inspiration for this episode. The article “The yin and yang of an invasive ornamental vine – Kudzu” by Brian Thompson and Michael Raupp, and fact sheets listed below were used as references.

http://www.clemson.edu/cafls/departments/esps/factsheets/household_structural/kudzu_bugs_hs50.html

http://www.ces.ncsu.edu/depts/ent/notes/Urban/kudzubug.htm

To learn more about kudzu bug, please visit the following web sites:

http://agnr.umd.edu/news/tracking-kudzu-bug-maryland

http://www.kudzubug.org/