Indiana's Department of Natural Resources will use low-flying planes to spray parts of Purdue University during May and June to eradicate an invasive insect that threatens tree populations.
The insect is the gypsy moth, one of North America's most devastating forest pests, which was first accidentally introduced to the United States near Boston in 1869 by an immigrant artist turned astronomer who dabbled as an amateur entomologist. The insect has slowly spread throughout the Northeast and into parts of the upper Midwest and Great Lakes states, including Indiana.
"You can liken the spread of gypsy moth to that of a slow burning forest fire," said Purdue entomologist Matthew Ginzel. "It's been in the U.S. for almost 150 years and has been inching westward. This eradication effort is like stomping out a cinder from this large fire that has landed in West Lafayette. In this way, we can slow the spread of gypsy moth. Larvae were discovered last summer on campus, and we're mandated to take action."
Gypsy moth larvae are small and spread by the wind or transport of wood. The gypsy moth caterpillar can grow up to 4 inches long and consume up to 11 square feet of foliage from early May until June. The moths have a large appetite for oak trees but also feed on numerous others species and, when abundant, can defoliate and kill trees. Additionally, the rain of caterpillars and their excrement from treetops can cause rashes or allergies.
"We've been working on gypsy moths for about 20 years in Indiana," said Scott Kinzie, nursery inspector and compliance officer with the Indiana DNR. "We're trying to keep it in the northern part of the state, basically in a line from Jay County running all the way up to Newton County. There is so much of it there we won't eradicate it, but we're trying to keep it from spreading further south. Hopefully, this will take care of it and will be the only time we will be treating the Purdue area."
Small aircraft, such as those seen flying close to the surface of Indiana farm fields, will do the same over parts of Purdue. A spraying application will take place in early to mid-May and then five to seven days later, followed by a third application in June. Areas to be sprayed are around Windsor Hall and areas further north and parts south of there.
DNR officials cannot yet provide the exact date for spraying. For that, they must watch for the optimal time, which is when caterpillars are small and most susceptible.
The first two applications will involve the use of Btk, a bacterium found naturally in soil and on leaves that produces protein crystals that kill specific kinds of insects. The third will involve pheromones, which essentially will disrupt male moths from finding females in order to mate.
"There is nothing to worry about as far as harmful effects to human health," Kinzie said. "Btk only affects caterpillars and nothing else. You might have a slight smell, but nothing big. You won't even smell pheromones."
The spray will take place just after sunrise – around 6-7 a.m. on each of the three days. Ginzel said the winds are often calmer then, which will decrease drift, and people will not be out and about as much as later in the day.
A campus text message will be sent out at the time of the spraying to alert the university community that it is taking place and to expect the low-flying aircraft.
An informational meeting open to anyone wanting to learn more about gypsy moth treatment is scheduled for 6 p.m. Monday (April 28) in the large conference room of the France A. Córdova Recreational Sports Center. Those with questions can also call the Indiana Department of Natural Resources toll-free at (866) NO-EXOTIC (663-9684).