COLUMBUS, Ohio — It turns out that one way to keep gypsy moths from multiplying is to disrupt their mating.
Whatever images that conjures up, they are probably not in sync with the actual method the Ohio Department of Agriculture uses. Picture a small, yellow plane flying a couple hundred feet above tree tops and buildings, spraying an organic product called SPLAT GM-O. Despite its whimsical name, the product has a serious intent: it confuses male gypsy moths amid their search for females.
Gypsy moths can kill trees by eating the leaves that allow for photosynthesis and growth of the tree.
SPAT GM-O is a synthetic version of the naturally occurring female gypsy moth pheromone. Harmless to humans and animals, SPLAT GM-O is a turn-on for male gypsy moths. By saturating areas with the synthetic pheromone, which has the consistency of lotion, a male gypsy moth doesn’t know how to find a female to mate with because suddenly the pheromone is everywhere. And female gypsy moths can’t fly, so they can’t seek out males. The result: fewer babies.
The process is akin to spraying a lot of a certain perfume in a large area with a lot of women, say a Justin Bieber concert. A man is stymied as he tries to find his girlfriend who wears that perfume. Everywhere he can smell the perfume, so he can’t possibly zero in on her. The romance is off, save for the slim chance he’ll run into her in the crowd on his way to the bathroom or to the parking lot.
For gypsy moths in Ohio, mating disruption starts June 14. Within about a week, the Ohio Department of Agriculture will have sprayed portions of 16 counties: Allen, Athens, Fairfield, Franklin, Hancock, Hardin, Licking, Marion, Morgan, Muskingum, Paulding, Perry, Ross, Union, Washington and Wyandot.
The approach to limiting gypsy moths is effective in areas with relatively low, but growing populations of the moth, said Dan Herms, a professor of entomology and an Ohio State University Extension specialist in the College of Food, Agricultural and Environmental Sciences at The Ohio State University. OSU Extension is the outreach arm of the college.
Saturating an area with SPLAT GM-O isn’t used in areas dense with gypsy moths because the male gypsy moths would be able to locate and mate with females – not by tracing their scent but by spotting them.
“They can still find each other,” Herms said.
The method of disrupting mating can be used with other insects, however the insect has to give off a pheromone and not all do. Also, it must be possible and not too costly to make a synthetic version of the pheromone, Herms pointed out.
Mating disruption is used to limit some populations of the peach tree borer, which feeds under the bark of peach, cherry and plum trees.
Earlier in the spring, aerial treatments were done in Ohio using a larvicide to kill the bug in its caterpillar stage in eight counties where a high number of gypsy moths were found: Hardin, Hancock, Jackson, Licking, Lucas, Marion, Muskingum and Union. Across the state, 51 of Ohio's 88 counties have established gypsy moth populations.
Sometimes the gypsy moth becomes popular in some unexpected places like it did last summer in downtown Columbus.
While in its caterpillar stage, it can feed on the leaves of over 300 different tree and shrub species, though it prefers oak trees. Although a healthy tree can rebound, repeated defoliations can make the tree susceptible to disease and pests, ultimately killing it.
“It becomes a nuisance for homeowners because you can have caterpillars crawling over all of your house,” Herms said.
Since the early 2000s, the state has been able to avoid major outbreaks, said Dave Adkins, gypsy moth program manager with the Ohio Department of Agriculture.
Helping in the efforts has been the spread of a fungus called Entomophaga maimaiga that kills the gypsy moth in its caterpillar stage.
“We’ve pushed the population of gypsy moths back to the point where the fungus has established itself,” Adkins said.
The fungus needs a wet spring to flourish and fortunately we had one this year, he said.
Though a problem in Ohio, the gypsy moth is not the state’s worst. These days the emerald ash borer damages far more trees, said Kathy Smith, program director of forestry for OSU Extension.
“If you drive around Ohio, the majority of the dead trees you see were killed by the emerald ash borer,” Smith said. “And there are a lot of dead ones out there now.”