Biocontrol agent tested to battle invasive kudzu bug

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 non-stinging 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.