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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Woollybears in the Garden

This article was published originally on 6/27/2007

The woollybear is a common and well-known caterpillar. Though most people have one kind of woollybear in mind, there are as many as 8 different species in the U.S. that could legitimately be called woollybears because of the dense, bristly hair that covers their bodies. Woollybears are the caterpillar stage of medium sized moths known as tiger moths. The best-known woollybear is called the banded woollybear. It is black at both ends and reddish-brown in the middle. This is the species commonly seen crossing the road in the fall of the year. This also the woollybear mentioned in winter-prediction mythology. Folk-lore claims that the longer the black at the ends of the body, the more severe will be the coming winter. As you might expect, science has debunked this legend. Another woollybear caterpillar seen in mid-summer in the garden is the yellow woollybear. The yellow woollybear is occasionally found feeding on the foliage of garden plants, flowers, soybeans and other plants. Reference books claim the yellow woollybear will feed on "many low-growing plants" and even trees and shrubs. The yellow woollybears are highly variable in color. The fine hairs covering the 1.0 to 1.75 inch long body vary from beige or yellow to dark reddish-brown. The caterpillars chew large irregular holes in the foliage and the extent of the damage depends on the number of larvae and the size and aesthetic value of the plants (for example, defoliation of soybeans is never an issue, while only a few woollybears can make young canna plants look quite unsightly). The yellow woollybear has two or three generations per summer. The adult moth is nearly pure white and is called the Virginia tiger moth. Special control actions against yellow woollybear caterpillars are rarely required. Hand picking caterpillars as they appear and before damage is extensive should be adequate.

Year of Publication: 
2007
Issue: 
IC-497(16) -- June 27, 2007