The European gypsy moth was introduced near Boston, Massachusetts in 1869. It is one of the most destructive forest pests in the US. Early attempts to eradicate this invader failed, and it has expanded its range over the northeastern states. Gypsy moths now range from Maine to Wisconsin, through northern Illinois, and into Ohio and Virginia.
While Missouri has no current infestations, gypsy moths were in Dent County and in northern Arkansas near Branson, Missouri in the 1990s. These infestations were successfully eliminated, delaying the introduction of the gypsy moth into our state.
Nationwide, gypsy moth caterpillars kill over a million acres of forest per year and cost citizens an estimated $868 million in damages annually. Because gypsy moths are non-native, they have few natural enemies in North America. Populations can reach outbreak levels in some years, severely damaging the forest and creating a nuisance for humans.
Missouri’s forests are highly susceptible to this pest. Thirteen of the top 20 preferred food species (mostly oaks) are common here. When combined with drought and other tree stresses, defoliation by gypsy moth could kill thousands of trees in Missouri.
Ultimately, our oak-dominated forests could change to forests with fewer oaks. With the loss of many oaks, wildlife that depends on acorns, like deer, turkey, and black bear, could undergo high population losses. From an economic perspective, Missouri’s oak timber industry would result in thousands of jobs and millions of dollars lost for the state.
Keeping this pest out of Missouri is the best way to protect Missouri’s forests. Humans can easily carry gypsy moths to new locations. Eggs, caterpillars, and pupae can hitchhike on firewood, outdoor equipment, and vehicles.
If you travel to infested states or move to Missouri from those areas, inspect your car and equipment to make sure no stowaways are on board.
Each summer, MDC partners with the Missouri Department of Agriculture, the US Department of Agriculture, the Missouri National Guard, and the US Army, to place several thousand gypsy moth traps across the state.
Traps are bright orange, triangular cardboard boxes usually placed on oak trees along roads. A pheromone lure inside the traps attracts male moths. These moths are then captured by the traps’ sticky-coated, inner walls.
If a moth is found, several traps will be placed in that location the next year to see if the moths are reproducing. These traps help us protect Missouri’s forests from this invasive insect, so please don’t disturb them!
Watch for unusual insect activity in your area, especially during the spring and summer. If you notice caterpillars with pairs of red dots and blue dots on their backs, contact your county’s MDC Forester. If possible, collect specimens or take pictures of the caterpillars.
If you travel during the spring and summer to areas infested with gypsy moths, look out for hitchhiking caterpillars, pupae, and egg masses on your vehicle and outdoor equipment.