May and June are the months when the gypsy moth caterpillars would eat the foliage from your trees, IF they are present. Now is the time to watch trees for gypsy moth presence.
According to the Iowa Department of Agriculture and Land Stewardship, we still have knowledge of only two infestations, one in Long Grove and the other in Clear Lake. Other infestations potentially exist in central Iowa as a result of last years introduction of egg masses on infested blue spruce trees, but those situations require further inspection and analysis.
Gypsy moth caterpillars start out only 1/4 inch long but grow to almost 3 inches by the time they are full grown. They are ashy- brown in color and have distinctive colored knobs or dots along their top side. The knobs are in pairs, one pair per body segment, and are red and blue in color. The gypsy moth caterpillars do not make any webs or tents as they feed. The common tent-making caterpillar seen at this time is the well-known eastern tent caterpillar.
See Extension Pamphlet Pm-1091, "Gypsy Moth" for additional detail.
This article originally appeared in the May 13, 1992 issue, p. 79.