MADISON – Adult gypsy moths will soon emerge and special traps will provide valuable data for the Wisconsin Department of Agriculture, Trade and Consumer Protection to plan future gypsy moth treatment sites. The traps are small boxes, bright green or red, and will be tied to tree branches. The traps are designed to catch and monitor the invasive gypsy moth. The moth flies through a small opening, then becomes stuck.
Trappers from the Wisconsin Department of Agriculture, Trade and Consumer Protection’s Gypsy Moth Slow the Spread Program began setting traps in mid-May and will set approximately 11,000 traps total in 48 counties, mainly in western and southern Wisconsin, by early July.
Traps are used as a method of population survey, not as a method of population control.
“Trapping tells us where the gypsy moths are and where they’re not,” said Chris Whitney, gypsy moth trapping coordinator. “It helps determine if an egg mass survey needs to be done in the fall to better evaluate the population and if an area may need an aerial treatment the following year.”
The traps only catch male gypsy moths because they can fly and the females cannot. To find each other and reproduce, the females release a pheromone for the males to detect and follow. This pheromone is undetectable to other insects and is used as a lure in the traps.
The traps will stay in place until the male moths stop flying in August.
“It’s important to leave the traps up during moth flight to get the data we need. Then, when the moth flight ends, we’ll take them down,” Whitney said.
If a trap needs to be set on private property and the owner is present, trappers ask the owner for permission to set the trap on the property. Trappers wear fluorescent vests and carry an identification card. If the owner is unavailable, trappers set the trap, and leave an information sheet and a phone number to call for more information.
“Most landowners are very cooperative, and we appreciate that,” Whitney said. “But, if a landowner wants a trap moved or removed, they can call the number listed on the trap and we can move the trap.”