Agriculture officials use stingless wasps to battle Prince George’s beetle problem

By Erich Wagner, Published: June 6

In the battle against an invasive tree-killing insect native to eastern Asia, state and federal agriculture officials have decided to use a strategy that lets nature do most of the work.

The emerald ash borer is a species of beetle that feeds on — and eventually kills — ash trees, which are prominently used in landscaping as well as stormwater and erosion control.

After years of failed attempts to eradicate or at least lessen the effect of the pests by destroying infected trees, officials with the U.S. Department of Agriculture and the Maryland Department of Agriculture in Cheltenham are trying to cut off the problem where it starts: with insect eggs. To do so, they have enlisted the help of another east-Asian insect: “stingless wasps,” which are smaller than fruit flies and lay their own eggs as parasites in ash borer eggs, eventually killing the host.

Although the tiny wasps are not a native species, officials said they are confident they will not become invasive.

Officials deployed the first set of wasp eggs onto infected trees May 30. The emerald ash borer beetles are particularly aggressive compared with native wood-boring insects, laying 70 to 100 eggs each, eating through the interior of a tree as larvae and then feasting on its leaves as adults, they said.

Ash borers are widespread despite earlier eradication efforts, which involved the destruction of 27 square miles of trees in Prince George’s County, where the region was first infested in 2003 via a tree nursery shipment from Michigan.

Since 2003, there have been reports of infestations in Charles, Howard, Anne Arundel, Washington and Garrett counties.

Officials said the program costs about $300,000 each year. Prior eradication efforts had cost as much as $1 million a year.

Charles Pickett, an agricultural inspector at MDA, said that not only do officials anticipate the eggs being more effective in stopping ash borers, but they hope they will be more capable of surviving and producing an enduring population to fight the invasive insect down to a manageable level.

“Each wasp can produce 62 eggs,” Pickett said. “We just want to get it to an equilibrium to control the borers so they’re not killing everything. We have native redheaded and clear-winged ash borers, which have always been here, but they only affect trees, they don’t kill them.”

Jian Duan, a research entomologist at the USDA and lead scientist in the effort to stop the emerald ash borer, said the wasps were one of several species tested before release for their potential effectiveness against the ash borer, as well as whether they would cause any adverse effects of their own.

MDA’s Cheltenham facility grows ash borer eggs to send to a lab in Michigan, which uses them to cultivate the wasps for use in Michigan and Maryland.

“[This species of wasp] and the emerald ash borer evolved together for many years,” Duan said. “It will be very hard for the wasps to switch to another egg.”

Dick Bean, program manager for plant protection and weed management at MDA, said the wasp effort is one of the last options available for saving the ash tree in Maryland. Given the region’s abundance of waterways and Chesapeake Bay tributaries, more conventional pest control means such as crop dustings of pesticides were out of the question.

“There’s just nothing on the market that we can use, especially [in Prince George’s County] because of environmental reparation efforts,” Bean said. “Biological control is one of the last hopes we have. But there’s no silver bullet yet.”

Bean said the first batch of eggs should at least make an impact on the ash borer population. Officials will keep track of the effectiveness of the wasps, as well as the dispersal system used thanks to a postdoctoral study conducted in conjunction with the effort by the University of Maryland.

Original Article Here

Agriculture officials prepare for emergence of latest wave of tree-killing beetles in SW Ohio

THE ASSOCIATED PRESS  

CINCINNATI — State agriculture officials are preparing for a new wave of tree-killing beetles that have infested southwest Ohio and other areas of the country to re-emerge.

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service predicts that Asian longhorned beetles, which have been feeding for much of the past year under the bark of trees, are about to emerge again in Clermont County east of Cincinnati.

State agriculture officials say they are taking added precautions, including requiring trucks to be covered with tarps when hauling infested trees to a site where woody material is chipped down enough to prevent the beetles from surviving, The Cincinnati Enquirer reported.

The midterm state budget finalized last week by the Ohio House and Senate includes $2 million for eradicating the beetle and for reforestation programs. The bill, which has been sent to Gov. John Kasich, does not specify how the money would be spent, but the Ohio Department of Agriculture plans to take a close look to determine the best use of the money, said Erica Pitchford, of the state agency.

Population levels for the beetles should be drastically reduced from last year because more than 7,000 infested trees have been removed, said Christine Markham, national director of the USDA's Asian longhorned beetle program.

But Markham says it's impossible to estimate the size of this year's population.

"We continue to survey, and we continue to find infested trees," Markham said.

Agriculture officials have surveyed about 116,000 trees in Clermont County's Tate and Monroe townships since last July, confirming nearly 8,300 infested trees and removing 7,400.

Since 1997, Congress has appropriated $463 million for Asian longhorned beetle eradication nationally, according to Markham.

The bullet-shaped, white-spotted black beetles tunnel into trees in the larval stage, eventually cutting off water and nutrients. They're especially attracted to maple trees, but 12 other types — including willows, poplars and elms — can be hosts for the bugs, creating a serious threat to forests and the timber industry.

The beetle can be difficult to detect, and well-trained individuals looking at trees from the ground detect, on average, about 30 percent of lightly infested trees, Joe Boggs, an assistant professor with Ohio State University Extension and OSU's entomology department, has said. He says trained climbers detect about 70 percent.

An environmental assessment released this month by the federal Animal and Plant Health Inspection Service lists a plan that would cut down every tree infested with the beetles and every other healthy tree they could attack in a half-mile radius as the most effective option for destroying the beetles, The Columbus Dispatch reported. Two other options in the plan would treat at least some healthy trees with a protective pesticide. The public has until July 9 to comment on the options.

Some residents concerned about losing healthy trees have said they want to combine removal of infested trees with chemical treatments of potential host trees.

The beetles, discovered last summer in Clermont County, are believed to have arrived from wooden materials in cargo shipments from Asia. Federal officials say the first U.S. infestation was discovered in 1996 in Brooklyn. Infestations in other parts of New York, Massachusetts, New Jersey and Illinois have resulted in the removal of tens of thousands of trees.

Original Article Here