Purdue professor responds to accusations of U.S. agroterrorism

Scientific research doesn't support a recent Serbian newspaper article accusing the United States of agroterrorism by introducing the western corn rootworm beetle into Yugoslavia during the early 1990s, said a Purdue University expert.

C. Richard Edwards, a professor of entomology, said it's more likely that the pest was accidentally introduced through passenger or cargo air travel. Historically other pests have been accidentally introduced to many countries by cars, boats, planes and trains, he said.

"I don't really believe that someone planted the insect there," Edwards said. "It is highly likely that the insects hitched a ride on an airplane into Yugoslavia in the mid-1980s, and they weren't observed until 1992 when plant damage was first noticed."

A Serbian official quoted in the article said the western corn rootworm was introduced in the early 1990s. Edwards said a few beetles couldn't cause the type of damage reported in one or two years. It usually takes five to seven years for a rootworm population to build up to damaging levels.

A representative of the U.S. Department of Agriculture's Animal and Plant Health Inspection Service asked Edwards to respond to the accusations because of his expertise on the western corn rootworm beetle, Diabrotica virgifera virgifera. Edwards is a leading researcher of corn rootworms, also known as diabrotica, and has been actively following the situation in Europe since 1994.

He chairs a subcommittee on diabrotica for the International Working Group on Ostrinia and other Maize Pests, is a United Nations Food and Agriculture Organization diabrotica network expert, and a member and adviser of the European Union's diabrotica project. He traveled to Belgrade, Yugoslavia, five times in the past seven years to research the insect and assist local entomologists.

In addition to his international work in western corn rootworm, Edwards is a Purdue Cooperative Extension field crops specialist who specializes in pests of corn, soybeans, small grains and alfalfa.

The western corn rootworm beetle and its damage were found near the Belgrade International Airport in 1992. Since then the insect has spread quickly throughout Central and Eastern Europe. The beetle is now found in Bosnia-Herzegovina, Romania, Hungary, Croatia, Bulgaria, the Slovak Republic, the Czech Republic and the Trans-Carpathian region of the Ukraine. It's also been found in Western Europe in northern Italy, southern Switzerland, near Paris and in eastern Austria.

Edwards said he thinks females carrying fertilized eggs were the first of the species to make the long voyage. He said they likely hitched a ride on an airplane from the Midwest - perhaps from Chicago's O'Hare International Airport, which had flights to Belgrade during the 1980s.

Once they landed in Belgrade, the beetles found conditions very similar to their native environment. Most importantly, they found cornfields less than 500 yards from the airport, Edwards said. Mature beetles feast on corn pollen, silks and leaves. In the United States, females lay their eggs in the soil from early July through August. Those eggs hatch in the spring and the larvae begin eating the roots of corn seedlings.

Typical corn rootworm larvae damage includes extensive root pruning that can cause lodged or goosenecked plants. Adult corn rootworms also can decrease pollination rates by feeding on corn silks. Yield losses of 10 to 15 bushels per acre are common, but losses greater than 50 percent can occur. A traditional corn to soybean crop rotation is the main means of controlling rootworm infestations in most of the United States, but a population of the pest has developed a tolerance to rotation. Those females lay their eggs in soybeans or other crops, taking the chance that corn will be planted there the following spring.

Edwards said the beetles in Belgrade are being genetically analyzed to determine if they're rotation resistant. If they are, then crop rotation may not be a viable control method.

"We are assessing the situation to determine the best course of action in either case." Edwards said.

Full story:

Purdue professor responds to accusations of U.S. agroterrorism: http://news.uns.purdue.edu/UNS/html4ever/021210.Edwards.rootworm.html

Related links:

C. Richard Edwards: http://www.entm.purdue.edu/directory/entm/106.htm
Corn rootworm Information: http://www.entm.purdue.edu/fieldcropsipm/insects/cornrootworms.cfm
Glas Javnosti homepage: www.glas-javnosti.co.yu

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