It's not always easy to spot the tiny green Winter Moth Caterpillar at a distance, but it's sure easy to see the damage they do to trees. If left unchecked, the invasive species can strip the leaves off fruit and evergreen trees in a season - and that's why the Wellesley DPW will be taking action to control the pests with a spraying program this month.
"In 2005 and 2006, we had incidents where this species would destroy every leaf on a tree," said Michael Quinn, Wellesley's deputy tree warden. "Since 2007, we've had a plan in place to manage them, and we're going to be doing more work this year as well."
The caterpillar, which has been a growing problem across the state, starts feeding on trees, particularly fruit trees and fruit-bearing bushes, in the spring. In about June, they burrow into the ground, emerging in November and December as small moths.
Quinn said in a release on the town's website that the spraying program, which will target about 880 of the town's approximate 3,000 public trees, began on April 16. It will continue through the end of May.
Trees will be sprayed between 5 and 10 a.m., and notices will be posted 24 hours before and after a tree has been sprayed.
"The compound we're using, called Conserve #SC, is the safest and most effective product we've been able to find to manage this pest," Quinn said. "Residents don't need to worry about staying indoors or wearing long-sleeve clothing when the spraying takes place, and we have all the materials safety data sheets on the product on file in our office."
The spraying is only one of the strategies Wellesley is using to combat the caterpillars, which are becoming a bigger problem across the state. Last year, Wellesley was the location of a pilot program developed by the University of Massachusetts to release predatory flies to eat the caterpillars.
"The program to release the flies is growing," Quinn said. "I know a lot of towns are hoping that we can eventually get this species under control."
Quinn has also published a series of guidelines for property owners whose trees are afflicted with the caterpillar.
"We recommend a certified arborist to develop a pest management plan, and suggest they call around to get at least three quotes on a price," Quinn said.
The total cost for the spraying program is between $7,000 and $10,000, Quinn said.
Sarah Thomas can be reached at email@example.com.