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Ornamentals and Turf |
We have not received any reports about stinging caterpillars, but they are probably on the horizon. Some of the stinging caterpillars are called slug caterpillars because their prolegs lack tiny hooks that most other caterpillars have, and the prolegs are so short that some of the slug caterpillars do resemble slugs. Several species of slug caterpillars have stinging hairs (saddleback caterpillars, hag moth caterpillars and stinging rose caterpillars) that can inflict a quite painful sensation. Some individuals are very sensitive to such episodes and may require professional medical treatment. Slug caterpillars overwinter in tough silk cocoons. Moths emerge the following spring and summer and lay flat eggs on leaves of various trees and shrubs. Puss caterpillars are one of the stinging caterpillars in the family of flannel moths. They produce a very painful sting when brushed (brushing against the caterpillar breaks tiny hollow spines which are filled with an urticating fluid which produces the painful stinging sensation which may last several hours). Swelling associated with the sting may be evident for several days. The adult is a lovely brown-colored moth with fluffy wings called a flannel moth. Puss caterpillars feed on various deciduous trees and shrubs, especially oak, elm, hackberry, maple, and sycamore. The moths, called flannel moths, are yellow-brown in color and have fluffy, wavy, white hairs. The young larvae sometimes feed in groups on the surface of the leaf. Older larvae devour the entire leaf. The caterpillars finally spin a dense cocoon in which it spends the winter. Puss caterpillars are usually not abundant enough to be noticed although rare outbreaks may be widespread and may cause noticeable defoliation. Two generations probably occur each year, and the winter is spent in the cocoon spun some place on the host tree. Sevin or one of the Bacillus thuringiensis (B.t.) pesticides should give adequate control, although B.t. is not very effective on older caterpillars. Usually only a few are found and chemical control is not needed. Crush with a stick or rock, if desired.
This week we have received two samples of this hemlock (Tsuga) pest from western North Carolina. The elongate hemlock scale is an introduced species. It has been collected from firs, spruces, hemlock, and yew. As these scale insects insert their mouthparts, they inject saliva which causes the needles to turn yellow. Predators and parasites help moderate the scale population. Crawlers are most numerous in May, but all life stages were present in one recent sample. We recommend that the tree be treated with one of the horticultural oils if the problem is severe. Egg laying shuts down with cold weather. Treat again in late May and three weeks later. Apply to undersides of needles. For more information, visit the following site on the Internet: http://www.fs.fed.us/na/morgantown/fhp/palerts/EHScale.pdf.
Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Last modified on August 11, 2003 by Stephen J. Toth, Jr.
