BY LINDA McGURK
Indiana Correspondent

WEST LAFAYETTE, Ind. — Just as Indiana Gov. Mitch Daniels proclaimed June Invasive Species Awareness Month, a new pest made its way into cornfields in the northern part of the state.

The Asiatic garden beetle – introduced into the eastern United States in the 1920s – is known to feed on more than 100 plants, but Christian Krupke, a field crops entomologist at Purdue University, was still surprised when he recently identified it in a cornfield in northern Elkhart County.

“It was interesting that we found it in field crops, because we’ve never found it there before,” Krupke said.

As the name implies, the Asiatic garden beetle has a preference for turf grass and plants commonly found in gardens, such as roses, dahlias, asters and chrysanthemums, but Krupke’s finding confirms that the grubs have adapted to feeding on corn, primarily in sandy soils.

In addition to this confirmed case, suspected sightings of larvae have been reported in the southern part of Elkhart County, as well as in Kosciusko, Lagrange and St. Joseph counties. Krupke expects those cases will be confirmed shortly.

The larvae are about to pupate and at this point new findings are unlikely, but in order to monitor the beetle in the future, Krupke recommended farmers who discover crop damage take a few minutes to dig around the plants until they find, and are able to identify, the culprits.

“If you do have a pest problem, make sure you know which insect is causing it. Don’t just assume it’s one of the usual suspects,” he said.

The Asiatic garden beetle is smaller than the Japanese Beetle, but Krupke said the two are related and should be treated similarly.
The grubs live and feed below ground, where they chew around the root and cause the plant to die. The afflicted cornfields were characterized by uneven stands and large gaps in the rows, and in one field the economic damage was significant.

“If the conditions are right – sandy soils, a high population (of larvae) and the corn is susceptible – there is a potential for high damage, but I don’t think it will become a key pest in Indiana. It’s worth noting in the group of secondary pests, and it’s something we should keep an eye on,” said Krupke.

The Asiatic garden beetle is one of more than 70 species of insects, pathogens and plants now categorized as invasive in Indiana, according to Christopher Pierce, Purdue University entomologist and state survey coordinator of the Indiana Cooperative Agricultural Pest Survey (CAPS). Seven species were added just last year.

“Every year there’s always something new,” Pierce said. “It’s a never-ending problem.”

Scientists and conservationists depend on the public to help fight exotic species, and that’s why Purdue University joined forces with The Nature Conservancy and Gov. Daniels to make June “Invasive Species Awareness Month.” The idea came from Wisconsin, where a similar program has been successful in increasing awareness of the problem, said Kate Howe, coordinator of the Midwest Invasive Plant Network (MIPN).

“(Invasive species) can cause a lot of different problems, the most obvious being that they displace native plant species. They reduce diversity and affect the animals that eat the plants or use them as habitats. Invasive plants can also change the amount of nutrients and water available in the soil,” Howe said.

One invasive plant known to cause a headache for farmers because it serves as an alternative host for Asian soybean rust is the kudzu plant, which was introduced in the 1800s and commonly used for erosion control along roadsides. Already prevalent in the Southeast, kudzu can now be found as far north as near Chicago and in several parts of Indiana, said Howe.

“In Indiana, we’ve taken a pretty proactive stance and try to eradicate it before it becomes a problem for farmers,” he said.
Homeowners, gardeners, farmers and others who suspect invasive insect or plant activity should contact the Purdue University Plant and Pest Diagnostic Laboratory at 765-494-7071 or the Indiana Department of Natural Resources at 866-NO EXOTIC (663-9684).

More information about invasive species is available at www.entm.purdue.edu/CAPS