Spongy moth caterpillars are a severe risk to oaks and different bushes in Chicago space

There can be some very confused moths this summer time in some components of Prepare dinner, DuPage, Kane, Kendall and different Illinois counties. And that’s excellent news for bushes.

The bugs are spongy moths (Lymantria dispar dispar, previously often known as gypsy moths), whose caterpillars are a severe risk to oaks and different bushes as a result of they’re “feeding machines,” in line with Stephanie Adams, a plant pathologist in plant well being care at The Morton Arboretum in Lisle. To fight their unfold, the Illinois Division of Agriculture is utilizing small planes to use a therapy known as SPLAT that retains the grownup moths from reproducing by disrupting their mating.

The therapy makes use of intercourse pheromones to lure male moths away from the females. It’s particularly focused to spongy moths, so it doesn’t have an effect on different species, and it’s biodegradable and unhazardous to people and different animals. The Arboretum is likely one of the websites the place SPLAT can be utilized.

Spongy moth caterpillars kill bushes by eradicating too lots of the leaves the bushes must reside. “The caterpillars eat at simply an unbelievable fee,” Adams stated. “A big caterpillar can eat a sq. foot of foliage a day.” Some 300 species of bushes are on the menu, together with oak, maple, apple, crabapple, hickory, birch, pine, spruce and willow. The moths’ populations are inclined to rise and fall in cycles, however when populations surge in an space, they’ll do widespread injury.

A tree could not die immediately, in line with Sharon Yiesla, plant data specialist within the Arboretum’s Plant Clinic. “But when a tree loses most of its leaves two or 3 times, it’s not going to have the ability to get well,” she stated. “And if an evergreen tree loses greater than 50 % of its needles, it might’t come again.”

The moths have been spreading steadily by means of North America for the reason that 1860s, once they had been imported as a part of a failed effort to start a silkworm trade. Their voracious caterpillars have brought on widespread injury to forests, parks and bushes in streets and yards.

The caterpillars, the larval stage of the moth’s life cycle, begin consuming on the prime of a tree’s leafy cover when they’re small. “We could not even know they’re there,” Yiesla stated. When you discover that your tree is getting skinny on prime, use binoculars to search for the caterpillars. They’re darkish coloured and lined with spiky hairs, with 5 pairs of blue bumps and 6 pairs of purple bumps alongside their our bodies and are about 2½ inches lengthy at their largest stage.

When you assume you could have spongy moth caterpillars in a tree, Adams instructed tying a strip of material across the trunk as a lure. “The caterpillars come down out of the cover at night time,” she stated. “And they’ll go beneath the material band. Within the morning, you’ll be able to squish them.”

Over the winter and into early spring, you might be able to see egg lots nearer to the bottom. They’re tan or mild brown and 1 to 2 inches throughout, with a spongy, fuzzy texture. The egg lots could also be on tree bark or any flat floor, comparable to garden furnishings, sheds or sculptures. “You may take away them and drop them right into a bucket of soapy water to kill the eggs,” Yiesla stated.

Spongy moths are unfold geographically once they lay eggs on movable surfaces comparable to autos, firewood or tenting tools that folks carry to new websites. Vacationers may help gradual the unfold by inspecting their cargo rigorously for the tawny-colored egg lots earlier than leaving dwelling, and by shopping for and burning firewood close to the campsite. Bringing wooden from dwelling can unfold eggs of spongy moths or different pests.

Seek the advice of with an arborist a couple of heavy infestation of spongy moth caterpillars. There are pesticides which will assist if the precise chemical is used, whether it is utilized by an expert on the proper time within the insect’s life cycle and if the tree isn’t already too badly harassed or broken. Spraying a big, mature tree is troublesome and prone to be costly.

To handle grownup moths, which emerge in June and July, pheromone traps can be found that lure in male moths. Nevertheless, Adams identified that the traps could not scale back your tree’s infestation as a result of they entice moths from far past your yard. “It’s possible you’ll find yourself with extra moths,” she stated.

For tree and plant recommendation, contact the Plant Clinic at The Morton Arboretum (630-719-2424, mortonarb.org/plant-clinic, or [email protected]). Beth Botts is a employees author on the Arboretum.