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Invasive Bugs in Connecticut May Be Adapting to Extreme Winters

Carole Cheah
/
Connecticut Agricultural Experiment Station

Scientists say this winter's extreme cold is having a limited impact on the state's invasive bugs, and it may even be making one insect stronger. It's called the hemlock woollyadelgid, and it was first identified in Connecticut in 1985.

Infected Hemlock trees can die off within four to six years of the adelgid's arrival.

"In the period of less than ten years it was found throughout the whole state," said Carole Cheah from the Connecticut Agricultural Experiment Station. "It kind of settles on the twig, on the hemlock twig, and spins this wool around itself, which protects it from the cold and the rain. It doesn't move, so a lot of people will think it's a fungus."

Credit Carole Cheah / Connecticut Agricultural Experiment Station
/
Connecticut Agricultural Experiment Station
Evidence of a hemlock woolly adelgid infestation. The bugs wrap themselves in a wool-like coating.

But it's a bug -- and it's a dangerous one. Infected Hemlock trees can die off within four to six years of the adelgid's arrival. Each year,  entomologists collect data hoping that Connecticut's cold winter weather will knock those population numbers down. "This year's data was very interesting," Cheah said. "Because of all this interest around the polar vortex, I was able to go out and sample ten sites throughout the state ...to see what effect that brief period of cold temperatures had on the adelgid."

Credit Carole Cheah / Connecticut Agricultural Experiment Station
/
Connecticut Agricultural Experiment Station
Hemlock trees that have been inspected by the Connecticut Agricultural Experiment Station. Fewer trees may require insecticide this coming spring.

Cheah found that in really cold parts of the state, like the northwest corner, bugs aren't dying off at the rates they once did. "I'm seeing populations in that part of the state which, prior to this, had suffered high mortality," Cheah said. "They're suffering much less mortality, which suggests there's some sort of adaptation going on from the survivors of previous winters. Which is not really good news."

But there is some good news. While bugs in the northwest are proving themselves more resistant, overall, the temperatures this winter did kill off about 80 percent of the state's adelgids. That means fewer hemlocks needing insecticide this spring. 

Patrick Skahill is a reporter and digital editor at Connecticut Public. Prior to becoming a reporter, he was the founding producer of Connecticut Public Radio's The Colin McEnroe Show, which began in 2009. Patrick's reporting has appeared on NPR's Morning Edition, Here & Now, and All Things Considered. He has also reported for the Marketplace Morning Report. He can be reached at pskahill@ctpublic.org.

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SOMOS CONNECTICUT es una iniciativa de Connecticut Public, la emisora local de NPR y PBS del estado, que busca elevar nuestras historias latinas y expandir programación que alza y informa nuestras comunidades latinas locales. Visita CTPublic.org/latino para más reportajes y recursos. Para noticias, suscríbase a nuestro boletín informativo en ctpublic.org/newsletters.

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