Lymantria dispar, formerly known as the gypsy moth, is an important defoliating insect of hardwoods in New Hampshire. A native of Europe and Asia (though we don't think we have the Asian varieties), Lymantria dispar was introduced into North America in 1869 when specimens were accidentally released in Medford, Massachusetts. Lymantria dispar is an outbreak pest and can remain at low levels for several years and then numbers can rise every few years. Many might remember the outbreaks in the early 1980s and 1990s. Unless areas are actively monitored, even moderate Lymantria dispar populations can exist unnoticed. Although these cycles are influenced by numerous factors, the low populations in New Hampshire in recent years generally are believed to be the result, at least in part, of a Lymantria dispar disease caused by the fungus Entomophaga maimaiga.
Recent outbreaks of Lymantria dispar in southern New England and some small populations in a few southern New Hampshire towns are worrisome. Forest health specialists are monitoring the situation. For forest landowners and managing foresters - We recommend as a best management practice not to harvest timber in a stands defoliated by Lymantria dispar until three (3) years after the outbreak subsides. Trees need time to recharge their starch reserves without additional root and soil stress.
We will add updates here as they become available. Last updated June 25, 2021.
More about Lymantria dispar
Lymantria Dispair fact sheet UNH Cooperative Extension
lymantria dispair pest alert US Forest Service
lymantria Dispair DEFOLIATION IN NH THROUGH THE DECADES
Lymantria Dispair Management in the United States: A Cooperative Approach
European Lymantria Dispair
'Pray for a Wet Spring' Eagle Tribune, 10/30/2016
Check your lawn furniture and outdoor toys for Lymantria Dispair egg masses before moving or taking a trip
Lymantria dispair Send Forest Animals Packing Video