3 (1 = rare 5 = annual)

2 (1 = very little damage 5 = plants killed)

These insects eat a wide range of trees and shrubs. Found mostly in the southern two thirds of Illinois, they occasionally show up in the northern third of Illinois.

Tree

• Black Walnut (Juglans nigra)
• Bur Oak (Quercus macrocarpa)
• Crabapple (Malus species and hybrids)
• European White Birch (Betula pendula)
• Gray Birch (Betula populifolia)
• Northern Pin Oak (Quercus ellipsoidalis)
• River Birch (Betula nigra)
• Silver Maple (Acer saccharinum)
• White Oak (Quercus alba)

They travel and eat enmass (usually thirty to a hundred) for protection. They also raise the front and rear portions of their body in mass when a possible predator (birds & other insects) appear. The caterpillars eat holes in the leaves, leaving only the veins. As the caterpillars grow larger, they eat the entire leaf, leaving just the petiole. There is a yellow to orange band around the caterpillar body just behind the head that is easily seen on older caterpillars; that is how they got their name. Young caterpillars are reddish-brown with white stripes; older caterpillars are black with yellowish stripes. The head is black.

These insects overwinter as pupae and the adult moths emerge in early summer. Eggs are laid on the lower side of leaves. Caterpillars are present for several weeks. Two to three generations occur per year.

Because this insect feeds in groups, it is easily controlled by pruning off the branch that they are feeding on or by pulling off the caterpillars by hand. Bacterial and chemical insecticides are effective. This caterpillar is most numerous in late summer when its feeding causes little damage to the tree. In these cases, no control is necessary.

Home, Yard & Garden Pest Guide
The Home, Yard & Garden Pest Guide (C1391) provides is written for homeowners and other residents and provides nonchemical and current chemical recommendations for controlling pests associated with trees, shrubs, turf, flowers, groundcovers, vegetables, fruit, and houses. In addition, you'll find detailed information about integrated pest management, pesticide safety, and pesticide application and calibration techniques. This publication may be purchased at your local University of Illinois Extension Unit office, or by calling 800-345-6087, or by placing an order online (search for "C1391").
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Illinois Commercial Landscape and Turfgrass Pest Management Handbook
The Illinois Commercial Landscape and Turfgrass Pest Management Handbook (ICLT) is written for professional applicators and provides nonchemical and current chemical recommendations as well as application timing information for all major pests of turf, woody ornamentals and herbaceous ornamentals. This publication may be purchased at your local University of Illinois Extension Unit office, or by calling 800-345-6087, or by placing an order online (search for "ICLT").
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U of IL - Distance Diagnosis through Digital Imaging
A free plant, weed, insect and disease identification service available through your local University of Illinois Extension office. Center Educators or State Specialists review & respond to information and digital images submitted by local Extension office personnel. Some samples may require further examination or culture work (nominal fee involved) at the U of IL Plant Clinic.
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U of IL - Plant Clinic
Services include plant and insect identification, diagnosis of disease, insect, weed and chemical injury (chemical injury on field crops only), nematode assays, and help with nutrient related problems, as well as recommendations involving these diagnoses. Microscopic examinations, laboratory culturing, virus assays, and nematode assays are some of the techniques used in the clinic.
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