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Exotic invaders
 by Rebecca Goetz
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Purdue entomologist Cliff Sadof tracks gypsy moth movement in Indiana and helps homeowners cope with the invaders. "When gypsy moths first enter an area, they have few natural enemies, so they do a lot of damage," Sadof says. (photo by Tom Campbell) |
Some exotic insects have made pests of themselves, too.
Thanks to an enterprising entomologist, Hoosiers will spend the next 10 years adjusting to an insect invader that's eating its way south through the state. Entomologist Francois Trouvelot brought gypsy moths from Europe to Massachusetts in 1869. He hoped to cross them with silk moths to create oak leaf-eating insects that could spin silk.
It didn't work.
Worse than that, some of the gypsy moths escaped from his backyard colony and found that they really enjoyed munching American flora. Since then, they've spread through the northeastern United States, northeastern Ohio and Michigan's lower peninsula. The line of infesting insects moves about 13 miles a year, annually munching leaves off of another three million acres of forest, says Purdue entomologist Cliff Sadof. So far, gypsy moths have eaten their way into five northeastern Indiana counties and two neighborhoods in Indianapolis, forcing nursery and Christmas tree producers to have their crops inspected before they can ship to uninfested counties. The moths have also made a mess of some backyards.
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A gypsy moth caterpillar can eat 11 square feet of foliage in its lifetime. (photo courtesy Cliff Sadof) |
"When gypsy moths first enter an area, they have few natural enemies, so they do a lot of damage," Sadof says. "Large, older caterpillars can eat all the leaves off a tree in a matter of days. Plus, under really infested trees, caterpillar droppings and smelly, diseased caterpillars can cover the ground, chairs or picnic tables."
Sadof tracks gypsy moth movement and tries to help homeowners cope. He developed a set of 100 slides that Purdue Extension educators use to show Hoosiers how to cope with invading moths. He also set up a Web site that describes the insect and ways to control it. Sadof has been promoting a 50-lesson curriculum that high school teachers can use to explain basic and applied ecology (see accompanying article).
In the end, Indiana homeowners will have to learn to live with the voracious moths. In selected areas, the Indiana Department of Natural Resources is trying to slow the moths' spread with aerial sprays. After the first wave of moths takes its toll, Sadoff says, natural enemies should start to keep the insects in check.
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