The battle against gypsy moths, pesky insects that threaten the health of oaks and other trees, will resume in earnest this month in more than 37,000 acres of DuPage County forest preserves and wooded areas of neighboring municipalities.
Forest preserve officials say they will work with the Illinois Department of Agriculture to spray for the moths beginning in late June and throughout July at the Blackwell, Big Woods, Warrenville Grove, St. James Farm, Herrick Lake, McDowell Grove, Danada, Hitchcock Woods, Egermann Woods, Hickory Grove, Greene Valley, Burlington Park, Pioneer Park, Goodrich Woods and West Branch Riverway preserves.
The moths are not native to this area and their caterpillars can defoliate entire oaks and other trees making the plants prone to disease and premature death, officials said in a news release. The spraying won't eliminate the harmful insects but it will minimize damage to area woodlands, officials said.
"With the tools available to us today, it's impossible to eradicate gypsy moths," said Tom Velat, the district's invertebrate ecologist. "But we can slow the spread."
Velat said the forest preserve has been fighting gypsy moths since the early 2000s.
"For the past couple of years, (gypsy moth) populations have been kind of low," said Velat, adding the insect goes through boom and bust cycles. "Now gypsy moth populations are beginning to become elevated again."
The district didn't have help from the state when it did its own treatments in 2008, 2009 and 2010. This time, the treatment is being done by the state.
"The Illinois Department of Agriculture proposed doing this treatment as a way to knock back these elevating populations," Velat said. "It's much more extensive because the state has jurisdiction over more than just forest preserve property. They can treat anywhere."
The state will use small planes flying roughly 100 feet above the treetops to spread green rice-sized flakes that contain gypsy moth pheromones, chemicals the females produce to attract males, officials said in the release. The flakes distract and confuse male moths to keep them from reaching females and successfully mating. The flakes only target gypsy moths, do not contain pesticides and are nontoxic to other wildlife and humans. They may stick to vehicles or pavement but should easily wash off.
The sprayings are weather-dependent, so there is no definite schedule for when each preserve and neighboring area will be treated. Officials said the preserves will remain open when the treatments take place.
For more information, contact the Illinois Department of Agriculture at (815) 787-5476.