2017-01-19 / From The Garden

Winter Moths Are Here in Force

The winter moth is a devastating insect which has been living in Rhode Island for quite a few years, having migrated from Cape Cod, though originally from Nova Scotia. 2015 saw infestations on Aquidneck Island in great numbers. Since then there has been little change.

According to the state website: “The Department of Environmental Management reports that winter moth caterpillars are prevalent throughout Rhode Island and are causing defoliation on oak, maple, ash, basswood, elm, beech and fruit trees.”

“In an effort to control the winter moth population, in early May researchers from DEM, in conjunction with URI and Joseph Elkinton, Ph.D. of the University of Massachusetts Amherst released a parasitoid fly that feeds exclusively on the winter moth in several Rhode Island communities. This is the second year that this parasite has been released in the state; the hope is that it will become established and eventually act as a control agent for the winter moth population. A natural enemy of the winter moth, Cyzenis albicans has been effective in mitigating large populations in Nova Scotia. However, it will take several years for populations of the parasite to catch up with the population and spread of winter moths.”

The spray that is effective in killing this moth is Spinosad. It is used in orchards to protect the trees from the tiny green, inchworms. If you have fruit trees, you can spray with horticultural oil (organic) in the spring, which will smother the eggs laid by the moths on your trees. Should you have larger, old or established trees that are way beyond your reach you will need to call a tree service to spray.

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