By Jennifer Keiper, WLS-AM 890 News

(CHICAGO) Gypsy moths: They can destroy one tree after another and four Illinois counties have been placed under a quarantine.

Cook, DuPage, Lake, and McHenry counties are already on the Gypsy moth quarantine list but just added are Kendall, Kane, LaSalle, and Will counties.

What it means is that to control the spread of voracious gypsy moth populations, the Illinois Department of Agriculture is going to treat infestations with pesticide alternatives and certify nursery or lumber products transported outside county borders.

Residents are also being asked to check cars and outdoor items for egg masses, live moths, or caterpillars.  The caterpillars have bundles of bristles over their body and two lines of colored warts along their back, some are red and the ones near the head are blue.

The caterpillars are around from May through mid-July, then they pupate – shedding their skin and becoming moths.  Gypsy moths can strip plants bare, causing tree death.  They will eat almost anything leafy-green.