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In Pursuit of Answers to Thwart Threatening Invaders


Published:
June 13, 2012
An APHIS employee at the Center for Plant Health Science and Technology Otis Lab prepared an agarose gel for electrophoresis of DNA.  The Otis Lab’s mission is to identify, develop, and transfer technology for the survey, exclusion, and control of plant pests and diseases.
An APHIS employee at the Center for Plant Health Science and Technology Otis Lab prepared an agarose gel for electrophoresis of DNA. The Otis Lab’s mission is to identify, develop, and transfer technology for the survey, exclusion, and control of plant pests and diseases.

It’s at that first alarm, when an invasive species is discovered within U.S. borders, that scientists at USDA APHIS’ Center for Plant Health Science and Technology (CPHST) power up to solve a biological puzzle and protect American resources.That first alarm also triggers a healthy apprehension of the unknown.  But a little apprehension is good, said APHIS entomologist Joe Francese, adding that confidence goes up the moment APHIS scientists learn more about how an insect pest arrives, thrives, breeds – and dies.

But until that eureka moment, no two days will be the same for Francese and his colleagues based at a former Air Force facility on Cape Cod, Mass. There, scientists are used to long days and the occasional trip overseas as they bring scientific rigor, an arsenal of knowledge and a good healthy sense of curiosity to the task of slowing or halting an invasive pest’s ravenous adventure in America.

That was the case in 2002 after the Emerald ash borer beetle was first detected in Michigan. It likely arrived in the United States hidden in wood packing materials several years prior to detection, but that’s about all that was known at that time, he said.

Enter that mixture of dogged perseverance, can-do attitude and spirit of calm deliberativeness toward finding solutions as the initial “what do we have here?” apprehension gives way to the scientists’ natural curiosity to explore.

“We knew almost nothing about the beetle’s behavioral or chemical ecology or what we could use to trap it,” Francese said. “Over the years, we’ve increased our knowledge tremendously, and we are constantly working to improve what we have and increase our chances of detecting EAB.”

Francese and others have traveled to the far corners of the Earth to collaborate with foreign scientists and to search for answers.  He has visited China several times to study the EAB’s behavior “mostly looking at flight propensity in relation to preferred and non-preferred host trees.”

David W. Williams, another APHIS entomologist, has carried out foreign exploration in East Asia “searching for parasitic wasps that kill and devour Emerald Ash Borer larvae.”

After returning from trips to South Korea and the Russian Far East with wasp parasites of the EAB, the species was identified and reared in the lab. “Because of its biological attributes, this species should be a particularly useful weapon in our EAB arsenal,” Williams said.

CPHST research had already led to discovery of three parasitic wasps with the potential to decrease EAB populations in an environmentally safe manner.

Currently a Brighton, Michigan facility is the site of APHIS’ mass-rearing efforts for the three known and tested EAB biocontrol agents- Spathius agrili, Tetrastichus planipennisi and Oobius agrili- all small stingless wasps native to China.  After testing at CPHST, the rearing process for these parasites was transferred to Michigan several years ago.

The wasps parasitize immature EAB lifestages by attacking and destroying EAB larvae and eggs.   The three wasps native to China were first released in 2007 in low numbers in Michigan following the completion of an environmental assessment which found them not to pose a risk to non-target insect populations.  In 2012, parasitoid releases will be made in fourteen of the fifteen states that harbor EAB.

Another scientific tool in the fight against the EAB to come out of CPHST is the purple trap used to detect and contain EAB. The traps yield distribution data used by State and Federal partners in the fight against the ash tree-killing beetle.

The APHIS scientists have the same advice to residents to combat the spread of invaders: Keep your eyes open!

“Be aware of new and different organisms in your environment,” Williams said. “If we are to have a chance at preventing the wholesale destruction of our forests and landscapes by foreign invaders, we need as many eyes on the ground as possible.”

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