If you see yellow planes above, they're spraying to keep the spongy moth off trees

Efforts to curb the invasive spongy moth will continue Wednesday in several suburbs, when low-flying, yellow "air tractor" planes will spray an organic, biodegradable mating disruption product in 12 different natural areas, including St. Charles, Geneva and Naperville.

With the ability to completely strip trees bare year after year, spongy moths have the potential to severely damage trees and forests. But since an Illinois county was first quarantined - Lake County in 2000 - prevention treatments have proved successful at slowing the insect's westward spread.

Weather permitting, the areas will receive a pheromone application that attracts and confuses male spongy moths, preventing them from breeding. The substance does not affect other insects, mammals or the environment, and it's made from food grade materials, according to the Illinois Department of Agriculture, which conducts the annual treatments in partnership with the United States Forest Service and The Slow the Spread Foundation.

Historically known as the "gypsy moth," spongy moth caterpillars have a feeding period that lasts between seven and 10 weeks through spring and summer. A single spongy moth caterpillar can eat 11 square feet of vegetation during its lifetime.

"Unlike the emerald ash borer, another nonnative pest which feeds exclusively on ash trees, the spongy moth is not a picky eater," according to a department news release. "It will devour almost anything leafy and green as it feeds on over 250 species of plants, but especially prefers oak and willow trees."

The mating disruption agent to be sprayed Wednesday is one of two methods used. A previous spraying of insecticide known as BTK or Bacillus thuringiensis kurstaki took place last month in areas in Aurora, Galena, Lemont and West Chicago.

Spongy moth specialists will be in the field for the spray program as it occurs. In total, 32,000 acres will be treated this year.

A map of the treatment plan can be found at tinyurl.com/IllinoisSpongyMothMap. More information about Slow the Spread, including product labels and frequently asked questions, can be found at tinyurl.com/ILSlowTheSpread.

• Jenny Whidden is a climate change and environment writer working with the Daily Herald through a partnership with Report For America supported by The Nature Conservancy. To help support her work with a tax-deductible donation, see dailyherald.com/rfa.