Research finds invasive kudzu bugs may pose greater threat than previously thought

Photo: Alejandro Del Pozo-Valdivia)

North Carolina, USA
April 15, 2013

The invasive kudzu bug has the potential to be a major agricultural pest, causing significant damage to economically important soybean crops. Conventional wisdom has held that the insect pests will be limited to areas in the southern United States, but new research from North Carolina State University shows that they may be able to expand into other parts of the country.

Kudzu bugs (Megacopta cribraria) are native to Asia, and were first detected in the U.S. in Georgia in 2009. They have since expanded their territory as far north as Virginia. The bugs have an interesting life cycle, which has been thought to be a limiting factor on far they can spread.
Eggs laid in the spring hatch into a first generation, which we’ll call “Generation A.” The immature bugs of Generation A normally feed on kudzu plants until they reach adulthood, when they have been known to move into commercial soybean fields. These mature adults lay eggs that hatch into Generation B during the summer months. Generation B kudzu bugs can feed on soybean crops during both their immature and adult life stages, causing significant crop damage.

Because the immature Generation A kudzu bugs have only been seen to feed on kudzu, researchers thought that the pest would not be able to migrate to northern and western parts of the United States, where kudzu doesn’t grow. But now it’s not so clear.

Under controlled conditions in a greenhouse laboratory, researchers at NC State found that immature Generation A kudzu bugs were not limited to feeding on kudzu – they were able to feed exclusively on soybeans, reach maturity and reproduce.

“Researchers began seeing some of this behavior in the wild in 2012 and, while those data aren’t quite ready for publication, our lab work and the field observations indicate that kudzu bugs are potentially capable of spreading into any part of the U.S. where soybeans are grown. And soybeans are grown almost everywhere,” says Dr. Dominic Reisig, an assistant professor of entomology at NC State and co-author of a paper on the research. “It also means that both annual generations of kudzu bugs could attack soybean crops in areas where the bug is already established, which would double the impact on farmers.”

The paper, “First-Generation Megacopta cribraria (Hemiptera: Plataspidae) Can Develop on Soybeans,” is a “rapid communication” article in the April issue of the Journal of Economic Entomology. Lead author of the paper is NC State doctoral student Alejandro Del Pozo-Valdivia. The research was supported by the United Soybean Board and the North Carolina Soybean Producers Association.

“First-Generation Megacopta cribraria (Hemiptera: Plataspidae) Can Develop on Soybeans”
Authors: A. I. Del Pozo-Valdivia and D.D. Reisig, North Carolina State University
Published: April 2013, Journal of Economic Entomology

ABSTRACT.
Megacopta cribraria (F.) (Hemiptera: Plataspidae) was first reported in 2009 near Atlanta, GA. The insect undergoes two generations per year. The first-generation is reported mainly in kudzu during May and June, with the second establishing on both kudzu and soybean during July and August. A greenhouse study was conducted to determine the suitability of two legumes as hosts for first generation M. cribraria. First generation M. cribraria successfully developed on caged potted soybean plants. Conversely, snap beans were not a suitable host under the conditions of this study. A range of 45-50 d was needed to transition from the egg to adult on soybean plants. Although this study was limited to the greenhouse, kudzu may not be an obligate host for the development of first-generation M. cribraria. An important implication of this finding is the establishment for this pest on spring-planted soybean and for the possible expanded geographic range for this pest beyond that of kudzu.


More news from: University of North Carolina

Biocontrol Agent Tested to Battle Invasive Kudzu Bug

From the USDA newsroom

By Jan Suszkiw
May 3, 2012 Don't let its common name fool you: The "kudzu bug" isn't to be trusted.

Sure, it will feed voraciously on the stems of kudzu, the "Vine That Ate the South." But Megacopta cribraria also has a taste for legumes, including soybeans. And in Georgia, where this native of Asia was first discovered in October 2009, there's worry the pest will infest peanuts, endangering the state's $2-billion legume crop.

U.S. Department of Agriculture (USDA) scientists and their collaborators haven't been idle, however. At the Agricultural Research Service (ARS) Stoneville Research Quarantine Facility in Stoneville, Miss., entomologist Walker Jones is evaluating a top natural enemy of the bug, the parasitic wasp Paratelenomus saccharalis. ARS is USDA's principal intramural scientific research agency.

The wasp is nonstinging and harmless to humans, pets and other animals. However, it lays its eggs in those of Megacopta's. Upon hatching, the wasp's maggot-like brood devour the pest's own developing embryos, reducing the size of the next generation.

Megacopta belongs to a unique insect family that doesn't occur anywhere in the Americas. Thus, importing its co-evolved natural enemies isn't expected to endanger native U.S. bug species, explains Walker, who leads the ARS Biological Control of Pests Research Unit in Stoneville. First, however, the wasp must pass muster on a long list of requirements to confirm its host specificity and environmental safety, starting with the quarantine trials.

Toward that end, Walker is screening eggs of native species of related bugs to learn whether the wasp will attack them, and so far it hasn't. The evaluations require a steady supply of bugs representing four families and 15 species sent to Walker by collaborators across the country.

Besides Georgia, Megacopta has also been reported in parts of Alabama, Tennessee, North Carolina, South Carolina and Virginia. A university-led effort is tracking the pest's spread and studying its basic biology, host crop range, economic impact, chemical control and vulnerability to native predators, parasites and pathogens.

Read more about this research in the May/June 2012 issue of Agricultural Research magazine.