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GARDENING IN GWINNETT: The kudzu bug: A new insect pest in our area

Last fall, several county agents in areas northeast of metro Atlanta began receiving phone calls from homeowners observing small insects congregating in large numbers on the sides of their homes. They were also found in high concentrations in nearby kudzu patches.

No one could figure what type of insects they were, so samples were sent to entomologists at the University of Georgia. They identified the bug as the bean plantispid, which is also called the lablab bug or globular stink bug. Locally, the pest has commonly been referred to as the "kudzu bug."

The insects are native to parts of Asia and have never been observed anywhere in the Western Hemisphere before now. Originally detected in nine counties in Georgia, it has now spread to more than 60 counties and in parts of the Carolinas. How it entered the country and became established remains a mystery.

With all of the international travel and being near one of the world's largest airports, it could have come here in many ways. In its native range in Asia, it feeds primarily on kudzu and other related plants. Kudzu was introduced to the Southeastern United States more than a century ago for erosion control. It became invasive and grows at an alarming rate. Over the years, it has spread throughout the region unimpeded. Kudzu is difficult to control, especially when it overtakes and covers large areas.

The kudzu bug is roughly one-quarter of an inch in size, oblong in shape and olive green to brown in color. It produces a foul odor when disturbed. The insects feed on kudzu, but so far, reports show they do only minimal damage to the vine. They also have been observed infesting soybeans, which is a major crop in parts of the state. Researchers are continually monitoring the insect to see if it presents a long-term threat to this crop.

During the fall, when the weather begins to cool and the days shorten, the kudzu bugs begin to seek shelter in secluded places to protect themselves from the winter cold. They often begin to congregate on the south and west sides of building structures to soak up the sun's warmth. The kudzu bugs are attracted to light-colored buildings. Their behavior is similar to Asian lady beetles, which commonly find their way into buildings during the fall months seeking shelter from cold weather.

If your home is invaded by kudzu bugs, what can you do to control them?

On the outside, apply an insecticide that is labeled for outdoor use to the parts of your home where the insects are gathering. Repeat applications may be necessary. If they get into your home, avoid crushing them since they will release a bad odor and can stain surfaces. Insecticide applications are generally not recommended for controlling them indoors.

The best course of action is to use a vacuum cleaner to remove them. Tightly seal the bag from the vacuum cleaner and then dispose of it. Keeping them out of your home in the first place is essential. Make sure screens are over windows are in place correctly. When the doors are closed, they should form a tight seal. Consider installing door sweeps if you do not have any. Make sure vents are also screened and seal up cracks or holes on the outside of the structure.

Long-term control of the insects presents a challenge due to their presence in large numbers combined with an abundant source of food and cover -- kudzu. Elimination of nearby kudzu patches is ultimately necessary for sustained control. The herbicide Round-Up can be used for controlling the vine. However, more effective herbicides are ones that contain the active ingredient triclopyr, which can be found in products such as Bayer Advanced Brush Killer Plus, Ortho Brush-B-Gon Poison Ivy Killer or other similar products.

Multiple applications of these chemicals are often necessary to totally eliminate kudzu from an area. Make sure you follow all label directions and safety precautions when using chemical pesticides.

It appears the kudzu bugs are here to stay and are one more insect pest for concern.

They are basically an invasive insect feeding on an invasive plant. As they continue to spread, they will be studied closely to learn more about their activity. So far, they have proved to be more of a nuisance pest. However, only time will tell if they do indeed pose a threat to soybean and other crops.

Timothy Daly is an Agricultural and Natural Resource Extension Agent with Gwinnett County. He can be contacted at 678-377-4010 or tdaly@uga.edu.