U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


Date of this Version


Document Type



Agricultural Research May/June 2013.


Each spring, the western corn rootworm (Diabrotica virgifera) awakens from its winter slumber to wreak havoc on corn crops across the United States. The pest emerges in larval form, hatching from small white eggs deposited beneath the soil and causing significant feeding damage to the grain crop’s roots. The toll on U.S. farmers: an estimated $1-2 billion annually in yield losses and chemical control.

European growers face a similar threat from the pest, which was first reported in a corn field near the Belgrade international airport in Serbia (formerly Yugoslavia) in 1992, but is presumed to have arrived a decade earlier. Since then, the insect has spread over Eastern Europe and partially over Western Europe. In response, scientists from the United States and Europe have been pooling their expertise and resources to launch a multifaceted counterattack. (See “Rooting Out Rootworm Resistance,” Agricultural Research, September 2010.)

On the biological control front, for example, a team of scientists from the Agricultural Research Service and the University of Neuchâtel (UniNE), in Switzerland, is field-testing different formulations to apply beneficial roundworms that prey on the pest. The roundworm, a species of entomopathogenic nematode known as Heterorhabditis bacteriophora, poses no danger to humans, pets, or livestock. But its lethality to rootworms may give corn growers another option for protecting their crops—together with use of insecticides, rotations with non-host crops like soybean, and Bt corn.