Gypsy moth caterpillars eat the leaves of many trees and shrubs, favoring oak, poplar, birch and willow. Infestations typically result in unsightly defoliation, and severe, repeated infestations can kill trees – especially when the trees are already stressed by drought or other factors. The moths are not native to North America, and after being accidentally introduced on the East Coast in the late 1800s, they have spread west state-by-state.
Fortunately, there are effective tools available to identify and control gypsy moth infestations. Minnesota’s early warning system against these moths is a deceptively low-tech network of small, cardboard traps set on trees or poles across the state. The cardboard traps contain a pheromone to lure in male gypsy moths. Once inside the trap, the moths become stuck to the sticky interior surface. Depending on trapping results, the final step may be a localized treatment to control the moths. Northeastern Minnesota is again expected to be a hot spot for gypsy moths in 2012, although the Twin Cities are also considered to be at high risk.
Minnesota is a member of a federal program called “Slow-The-Spread of Gypsy Moth” (STS). For more than a decade STS has helped Minnesota delay the full-scale invasion of gypsy moths even as the pest’s numbers swelled in Wisconsin and other eastern states.
“For nearly 40 years, the Minnesota Department of Agriculture and our partners have protected Minnesota’s trees from this nasty pest,” MDA Plant Protection Director Geir Friisoe said. “Our efforts have saved important industries like tourism and forestry from economic harm. Each year we delay the moths is a victory for the environment and the economy.”
For the first time in 2012, MDA will also conduct a pilot survey for five invasive pests with similar destructive habits as gypsy moth. The list includes Asian gypsy moth, nun moth, rosy moth, Siberian moth, and pine-tree lappet. This survey will focus on Duluth and the Twin Cities. To date none have been found in Minnesota.
Minnesotans can help fight gypsy moths and other defoliators by taking two simple steps to avoid giving the pests a ride to new areas. First, don’t transport firewood. Second, when leaving any area infested with gypsy moths, check tents, vehicles and other outdoor articles for the moths’ distinctive fuzzy, buff-colored egg masses. More details can be found at www.mda.state.mn.us/gypsymoth or www.hungrypests.org.
