Researcher says three insect invasions converging on Southeast Missouri

Thursday, June 23, 2011

SIKESTON, Mo. -- If they aren't already, farmers and homeowners should be on the lookout for several insects infesting Southeast Missouri and threatening damage to plant life.

According to Dr. Sven Svenson, assistant professor of agriculture at Southeast Missouri State University, and Dr. Kelly Tindall, research entomologist for the Delta Research Center in Portageville, Mo., three insects of concern are the Japanese beetle, the emerald ash borer and the gypsy moth.

The insects are attacking most of Southeast Missouri's major forest and landscape species and many commercially important food crops, Svenson said. Complete infestation is projected to occur in the area sometime within the next two to 25 years, according to Svenson.

Japanese beetle adults can feed on plants until they are defoliated, and beetle larvae damage grass species by feeding on roots. Emerald ash borer larvae feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients, thereby killing them. The larval stage of the gypsy moth can consume all of the foliage from trees and other plants, with repeated defoliation eventually killing the plant.

Native to Japan, the Japanese beetle was first found in the United States in 1916 near Riverton, N.J. Spreading out from New Jersey, the front wave of Japanese beetles arrived in Southeast Missouri several years ago and is progressively moving south.

Tindall said early this month Japanese beetles began showing up for the first time this year in trap captures in several counties in southwest, east central and Southeast Missouri.

"Japanese beetles have a huge host range," Tindall said.

They are pests of ornamentals, grapes, turf, corn and soybeans.

"People don't like them because they feed on roses. That is a prized plant for most people," Tindall said.

The wine industry, in particular, is being hit hard by this pest as are golf courses because the larvae will feed on the turf, the entomologist explained.

"This is a statewide problem. Farmers typically know about it, but as the beetles move in, more of the general public are learning about them," Tindall said.

Recent observations suggest that the first couple of years you may catch a couple of beetles and at some point afterward, captures may be in the thousands a night.

Based on last year's trap captures, Mississippi County probably is infested with them the most. In 2010, Mississippi County captured 12,000 over a three-day capture period and Stoddard County captured 108 over a three-day capture period, Tindall said.

According to the University of Missouri Extension's Integrated Pest Management Pest Monitoring Network, the following Japanese beetle trap collections were reported: five in Mississippi County on June 8; eight in Portageville on June 15; 200 in Scott County on June 17; and 12 on June 14 and 17 on June 17 in Stoddard County.

Currently, Wayne County is the only county in Missouri under quarantine for emerald ash borer. Missouri's first reported emerald ash borer infestation was in July 2008 at the Wappapello Lake area.

However, the pest is a concern for residents in all counties.

"Anyone who has an ash tree on their property is at risk for this pest," Tindall said.

She suggested buying local firewood when camping to reduce the risk of transferring the pest from town to town or even state to state.

"And if you don't use all the firewood, don't bring it home with you," Tindall said.

The gypsy moth was introduced to the East Coast in 1869 and since then has spread slowly westward. When it arrives, the gypsy moth will be especially devastating to Missouri forests because one of its favorite foods is oak leaves, according to the Missouri Department of Conservation.

The Departments of Conservation and Agriculture and numerous other state and federal agencies cooperate on a monitoring program to detect any introductions of gypsy moth. Each year, several moths are found that have been accidentally brought into Missouri from infested states. Spot infestations of gypsy moth were found in the 1990s in Dent County and in northern Arkansas near Branson. These infestations were controlled, delaying the introduction of gypsy moth into Missouri for the time being.

In Southeast Missouri, Svenson said, "Trial areas are needed to identify species and cultivars of species that can survive and thrive in the presence of these pests."

Information obtained from the previously infested regions of the United States will aid in the successful selection of test species that can live despite the invading insects, he said.

Native insect species are also at risk of being affected by the spread of these insects.

"Any time a new insect enters an ecosystem, there is a possibility that the new insect can displace the native species," said Tindall.

Chemical and physical control measures are available, but none are completely effective, and many of the treatments may have undesirable or unintended side effects, she said.

"All the insecticides that go out to get rid of the new insects could impact native species," Tindall said.

For the homeowners who choose to protect their gardens, read product labels, follow the directions and use personal protective equipment during the application process, Tindall added.

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