2017-02-02 / Regional News

State environmental officials predict another year of defoliation from Gypsy Moths

Following widespread defoliation by the invasive gypsy moth in 2016, state environmental officials are predicting another season of higher than usual caterpillar feeding in 2017 and are encouraging homeowners to survey trees on their property to identify egg masses due to the absence of leaves, and to begin the scheduling of the treatment process with a certified arborist or licensed pesticide applicator. Egg mass surveys performed by foresters throughout the state indicate the likelihood of a higher than normal gypsy moth caterpillar hatch this spring.

Gypsy moth populations in Massachusetts have generally experienced cyclical patterns, but have been controlled by natural factors, including weather, natural and introduced enemies, and the resilience of Massachusetts forests to withstand defoliation. Recent drought conditions have limited the effectiveness of a soil borne fungus, Entomophaga maimaiga, which has helped keep gypsy moth populations in check since the last large outbreak during the 1980s. Though trees are able to overcome a single defoliation event, successive years of severe insect feeding, or the addition of other stressors such as drought, can lead to long-term tree damage or tree mortality.

“The Department of Conservation and Recreation remains steadfast to combating invasive species like the gypsy moth to ensure the Commonwealth’s natural resources are protected for all to enjoy,” said DCR Commissioner Leo Roy. “The agency will continue to monitor the situation; however, by sounding the alarm early, we hope to provide the public with ample opportunity to treat their own trees before it is too late.”

“The Department of Agricultural Resources remains committed to assist our sister agencies and the public combat the gypsy moth problem,” said MDAR Commissioner John Lebeaux. “It is important the public look at all options when attempting to control gypsy moths. If hiring a company to help with the issue please contract with a well-trained, licensed applicator. We hope that early detection and education will lead to the most effective and environmentally appropriate response to this problem.”

In areas that have seen repeated defoliation by gypsy moth, forest health specialists recommend targeted treatments utilizing a biological pesticide such as Btk (Bacillus thuringiensis var. kurstaki) to reduce gypsy moth populations to more manageable levels. Trees should be checked beginning in the first week of May for signs that the egg masses have hatched; look for tiny, black, hairy caterpillars, only 3-5 mm long, traveling from the pink egg masses in search of food, or congregating on the undersides of the leaves of oaks and other trees. Individuals interested in pursuing treatments should hire a certified arborist or licensed pesticide applicator to protect their trees in a safe and effective manner.

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