BROWNTAIL MOTH

  Dark brown with a broken white stripe on each side and two conspicuous red spots on the back. They grow to 1.5 inches in length. 

 The caterpillars feed on the leaves of many hardwood trees and shrubs.  Common host trees and shrubs include:

    • Oak, apple, crabapple, cherry, hawthorn, shadbush, serviceberry, and rugosa rose. 

  Feeding by browntail caterpillars can cause reduced growth and branch dieback.  A number of years at high population levels can lead to mortality of trees and shrubs.  

  The browntail caterpillar has tiny (0.15 mm) hairs that on sensitive individuals cause a skin rash similar to poison ivy and/or trouble breathing.  The microscopic hairs break off the caterpillars and are everywhere in browntail infested areas; on trees, lawns, gardens, decks, picnic tables and in the air. The hairs can remain toxic for up to THREE YEARS so although the problem is worst from May to July, they may cause a reaction at other times of year as well.  Wind or activities such as mowing, leaf-blowing, etc., can stir up the hairs, leading to a reaction. The rash and trouble breathing can last anywhere from a few hours to several weeks.  It is caused by both a chemical reaction to a toxin in the hairs and physical irritation from the barbed hairs. Contact your physician if a reaction is severe. 

  Only seen in July and August. Both sexes of the browntail moth have snow white wings and a tuft of dark brown hair on the tip of the abdomen. The moths are strongly attracted to light.

 Adult moths emerge from cocoons in late July and August, laying clusters of eggs on the underside of leaves. 

 Browntail overwinters as colonies of caterpillars in white silk tightly woven around a leaf or leaves in trees or shrubs.  These webs contain 25 to 400 caterpillars, are spun in the early fall, and remain firmly attached to the tips of small branches all winter.  The webs are often confused with silken structures formed by other less serious species of moths.