ST. PAUL, Minn. – The Minnesota Department of Agriculture (MDA) is setting nearly 23,000 gypsy moth traps across eastern Minnesota this spring as part of its annual program to monitor the state’s forests and urban areas for infestations of the destructive tree pest.
While emerald ash borer – the state’s other high-profile tree pest ? attacks only ash trees, gypsy moth caterpillars devour the leaves of many tree species including oak, poplar, birch and willow. Severe infestations and repeated defoliation can kill trees, especially when the trees are already stressed by conditions such as drought. Fortunately, there are several effective treatment options for dealing with gypsy moths – unlike emerald ash borer.
The MDA’s early warning system against the moths is a network of small, cardboard traps attached to trees or poles. The cardboard traps contain a pheromone to lure in male gypsy moths. Once inside, the moths become entangled in the sticky interior. In mid-summer and again in the fall, workers remove the traps and count the moths inside. When MDA finds a significant number of moths in an area, it moves in to conduct treatments designed to control them.
MDA’s 2009 monitoring program discovered record numbers of gypsy moths moving inland from the North Shore of Lake Superior, but the program found very few gypsy moths in other parts of the state. These 2009 detections prompted MDA to develop plans for control treatments later this spring and summer along the North Shore.
MDA Plant Protection Director Geir Friisoe said monitoring is a key part of the fight against gypsy moths.