2013-12-19 / News

Winter moths begin invading Jamestown


Dr. Joseph Elkinton of the University of Massachusetts Amherst releases parasitoid flies in Jamestown in the spring of 2013 to control winter moths. The project takes several years to become fully effective. 
Photo/Jim Rugh Dr. Joseph Elkinton of the University of Massachusetts Amherst releases parasitoid flies in Jamestown in the spring of 2013 to control winter moths. The project takes several years to become fully effective. Photo/Jim Rugh Earlier this year, Dr. Joseph Elkinton of the University of Massachusetts Amherst began implementing a biological control program in Jamestown to help thwart the pesky winter moths that are active this time of year.

Elkinton, with the help from Heather Faubert of the University of Rhode Island, released a parasitoid fly in early May in the north end. The tiny-sized flies feed exclusively on winter moths. Jamestown became the third Rhode Island site in three years where Elkinton introduced the program – the others being Charlestown and Roger Williams Zoo.

The hope is that the parasite 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 limiting populations of winter moths 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.

Therefore, according to Jim Rugh of the town Tree Preservation & Protection Committee, the winter moths will still bug Jamestowners for as many as five more years.

According to the state Department of Environmental Management, adult male winter moths are now in flight searching for flightless females for mating purposes. These non-native invasive pests were first discovered in Rhode Island in 2004. The state received reports of them being found throughout much of Rhode Island, and particularly in the coastal communities of Warwick, Cranston, South Kingstown, Charlestown and Westerly. They have also been reported in Cumberland and Lincoln in the northeastern part of the state. Rugh says there is a healthy population of winter moths in Jamestown as well.

According to state forester Bruce Payton, the DEM began receiving reports of the emergence of winter moths beginning in late November, and expects to receive additional reports through the end of December.

“Homeowners describe sometimes seeing hundreds of moths congregating around porch lights,” he said. “It is no coincidence that this past spring these same communities witnessed an astonishing number of caterpillars defoliating oak, maple, ash, basswood, elm, beech and fruit trees.”

Leaves on affected trees are filled with small holes and have a shotgun blast appearance.

Winter moth caterpillars are pale green with white longitudinal stripes running down both sides of the body. Also referred to as loopers or inchworms, they are often found in association with both fall and spring cankerworms that look similar and have similar feeding patterns.

Payton noted heavily defoliated trees will put out a second flush of leaves, which depletes a tree’s stored energy supplies.

“This is very stressful for the tree,” he said.

Adequate water is critical to trees during the time of defoliation, so if drought conditions occur, supplemental watering of the refoliating trees may be necessary for their survival. Fertilizer application is not recommended at the time of defoliation. If residents decide to fertilize, they should contact a licensed arborist. The ideal time for fertilization is late winter or very early spring, but no later than mid-April.

Rhode Island residents are asked to call Paul Ricard of the Department of Environmental Management at 568-2013 ext. 17 to report sightings of the winter moths.

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