NEW HAVEN, Conn. (WTNH) – State agricultural officials say some rain we had over the last week is helping put an end to this year’s gypsy moth caterpillar infestation in parts of the state. Rainfall helps a natural fungus thrive, that is deadly to the caterpillars. The Connecticut Agricultural Experiment Station announced Monday that are widespread reports of dead and dying gypsy moth caterpillars around the state.
The problem was widespread in Connecticut in 2015, with more than 175,273 acres having trees stripped of leaves, the worst of it in Middlesex, New London, and parts of New Haven and Windham counties. The spring of 2015 was very dry in eastern Connecticut, so there was little control of the caterpillars by the gypsy moth fungus. The problem wasn’t as bad in western and central Connecticut in 2015.
With recent rains, the water-fueled fungus has been killing off the caterpillars this season, and should keep the problem from being as bad in 2017. “It is likely that this pathogen will knock back the gypsy moth population and help prevent another large outbreak in 2017” said State Entomologist Dr. Kirby Stafford.
The gypsy moth was first detected in Connecticut in Stonington in 1905. State agriculture officials say they don’t believe this recent outbreak will mean a return to widespread deforestation that the state dealt with in the early 1980s. If the trees in your yard were stripped clean, they should make a full recovery. Healthy trees can survive defoliation. The result could be different for older or diseased trees.
There is only one generation of the gypsy moth each year. The caterpillars hatched from the buff-colored egg masses in late April this year. An egg mass may contain 100 to more than 1000 eggs laid in several layers. A few days after hatching, the ¼ inch long caterpillars will ascend the trees and begin to feed on new leaves. These young caterpillars deposit silk trails as they crawl and, as they drop from branches on these threads, may be distributed on the wind. Larger caterpillars generally crawl up and down tree trunks and feed mainly at night. They seek cool, shaded protective sites during the day. However, under outbreak conditions with dense populations of caterpillars, they may feed continuously day and night and crawl at any time. The caterpillars generally complete their feeding sometime around the end of June, pupate, and transform into an adult moth in about 10 to 14 days. Male moths are brown and can fly. The female moths are white and cannot fly. Each female moth will lay a single egg mass and die. These eggs will pass through the winter and larvae will hatch the following year in late April or early May.