MAA NEWS MAA NEWS Fall2017_w-1

NEWS FALL 2017 A Tale of Two Caterpillars: Winter Moth and Gypsy Moth Reviewed for 2017 by Tawny Simisky way in, and begin feeding. Partial defoliation of the host is common, with leaves appearing tattered or shredded and riddled with holes. Once the cater- pillars are mature, they drop to the soil to pupate, typically in late May or early June. In 2016, Dr. Joseph Elkinton (Professor in the Department of Environmental Conservation at UMass Amherst) and his laboratory noted fewer winter moth pupae at most research locations across the state than had been observed previously. This seems to have led to fewer adult moths pres- ent in November and December of 2016, fewer eggs laid, and reduced winter moth caterpillar numbers and activity for many MA locations in 2017. The ubiquitous gypsy moth caterpillar, captured at Quabbin Reservoir, Belchertown, MA this summer. Photo by A. Simisky. As fall’s arrival is upon us, we take a look back at the 2017 activity of two notorious defoliators in Massachusetts: winter moth (Operophtera brumata) and gypsy moth (Lymantria dispar). WINTER MOTH ON THE DECLINE IN 2017 Winter moth is a non-native, invasive insect first identified in Massachusetts in 2003. Since then, winter moth has been a menace to eastern Massachusetts communities dealing with this pest in near-constant outbreak, witnessing early spring defoliation of oaks, maples, apples (preferred), among other species. Winter moth overwinters in the egg stage, each nearly wingless (brachypter- ous) female moth depositing 150-350 tiny eggs in bark crevices, on lichen, etc. of the trunk and branches of their hosts. Egg hatch typically occurs between late-March and early-mid April in Massachusetts, or when approxi- mately 20-50 Growing Degree Days (base 50°F) have accumulated. Newly emerged, tiny caterpillars crawl and disperse via ballooning (spinning a silken thread, catching the wind to be carried to a new location) to host plant buds as they expand. If the buds are open enough, the caterpillars will wriggle their Winter moth egg hatch was first reported in Franklin, MA on 4/6/17 by Heather Faubert of URI, in advance of most of the Massachusetts win- ter moth population. The Elkinton Lab reported 50-95% winter moth egg hatch by 4/19/2017 from observations in Falmouth and Hanson, MA. When sampling for winter moth in host plant buds, win- ter moth numbers were observed to be greatly reduced this year. In past similar surveys, it was not uncommon to find 20+ winter moth caterpil- lars per host plant bud sampled; early in the 2017 season, however, 1-2 caterpillars were observed in every other bud or so. Scouts reporting to UMass Extension’s Landscape Message from the Cape Cod Region (Barnstable, MA), Southeast Region (Han- son, MA), and the North Shore Region (Beverly, MA) noted that winter moth damage on hosts, such as maple, was dramatically reduced from previous years. (continued on page 3) PROUD FOUNDING PARTNER OF Where the best in the tree industry come together. NewEnglandGROWS.org