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Second phase of gypsy moth spraying to begin

Starting in late June, the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP), will begin another round of aerial treatments to control gypsy moths in 15 counties.

Phase two targets adult male moths, whereas phase one earlier this spring, targeted gypsy moth caterpillars. Residents in counties that include Chippewa and Rusk, can expect loud, low-flying, yellow planes as early as 7 a.m., through mid-July.

Efforts in those counties will focus on where gypsy moth populations are low or beginning to build, to slow them from spreading farther west.

Planes contracted by the U.S. Forest Service, in a joint project with the DATCP, will apply an organic, biodegradable mating disruptor, to 31 sites in the counties in the western third of the state.

The mating disruptor is a pheromone that female moths release to attract males for mating. When applied to a large area, it prevents male moths from finding a female. The mating disruptor is in the form of small waxy droplets that slowly release the pheromone.

Research shows that applying the mating disruptor to the forest canopy, can reduce gypsy moth populations by nearly 90 percent in the subsequent year. The scent that is released is specific to male gypsy moths and will not interfere with the life cycle of other insects.

The mating disruptor is not harmful to people, animals, birds or other insects. According to the Environmental Protection Agency, there is no health risk to humans, nor have any adverse effects been reported in the two decades that the pheromone has been used for gypsy moth control.

The gypsy moth has harmful effects on local communities. The cost of removing dead trees can range from hundreds to over $1,000, and the loss of mature trees decreases property value. Caterpillars also shed bristly skin that can irritate people’s eyes, skin and respiratory system.

The DATCP will start spraying in southwestern Wisconsin, and end in the northwestern part of the state in mid-July. Dates and times are weather dependent.

Maps of treatment areas are available at