Winter mortality was especially high in the northwest corner of Connecticut.
This year's cold winter killed off a high percentage of insects that target Connecticut's hemlock trees. That's good news for forests and for landowners in the state.
Carole Cheahis a research entomologist with the state's Agricultural Experiment Station, and she said hemlock woollyadelgids are strange little bugs. "It actually doesn't even look like an insect. It's like a little woolly white cotton ball on the underneath of hemlock trees," Cheah said.
Hemlock woollyadelgids feed on trees like the Eastern or Carolina hemlock by attacking the stems of their youngest branches. That can weaken and kill the trees.
Cheah said the bugs are strange beyond just their appearance, too. Unlike most insects that hibernate during the winter, hemlock woollyadelgids stick around, feeding and developing as the snow falls.
Here in Connecticut, Cheah has been tracking how the bugs fared during the winter for the past 15 years. Last year, she said the average adelgid winter mortality was about 84 percent. "This year, it's considerably higher, which is great news for the forest, it's great news for homeowners, and landscapers, and forest managers," she said. "It's about 90 percent, and there was much less variation, which to me seems that we reached really killing temperatures this year, especially in February."
Winter mortality was especially high, Cheah said, in the northwest corner of Connecticut. Places like Norfolk and Salisbury had mortality rates running as high as 99 percent.
Cheah said any die-offs greater than 90 percent will noticeably reduce population numbers in the state. That's important for hemlock trees -- since it's one less thing conspiring to kill them, but Cheah said it's also for important homeowners. Fewer bugs means less of a need to spray insecticide treatments on plants, which can be good for consumer pocketbooks.
