5-18-2004 |
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THEY AREN'T GYPSY MOTHS, BUT SPRING
DEFOLIATORS ARE Contact with landowners, West Virginia Division of Forestry personnel and WVDA staff places defoliation as occurring in Cabell, Kanawha, Lincoln, Mingo, Putnam and Wayne Counties. Numerous white oaks are also being defoliated along Rt. 50 between Parkersburg and Clarksburg and there is inchworm defoliation occuring in Mineral and Hardy Counties. Defoliation has been reported as moderate to heavy in all locations. It is not unusual for inchworms, or loopers, to show up in large numbers. These are native insects that periodically have high populations that may be triggered by stress, such as drought conditions. They are present in high numbers for 2-3 years and then collapse due to high corresponding numbers of predators and parasites. In the western part of the state this spring, the looper defoliation is occurring along with that being caused by a number of other miscellaneous oak-feeding caterpillars, which is making the defoliation very noticeable. The common oak moth, Phoberia atomaris, is also a native insect, nearly an inch long when mature, hairless, and generally dark brown and black in coloration. They have two rows of small, black triangles that occur down the length of the back of the caterpillar. This pest prefers white oak as a host. Loopers come in a variety of different colors, but they all have the typical tail-to-nose "measured" movement. In the eastern part of the state, they are defoliating a larger variety of hardwood hosts such as oak, maple, wild cherry, elms, and hickories. Some of the defoliated areas are several acres in size. "This is the second year for the looper and common oak moth defoliation," states Forest Entomologist Sherri Hutchinson. "We are already getting calls on large, shiny-green beetles called caterpillar hunters in the areas where the defoliation is occurring. This is just one of the predators that show up when caterpillar populations get high." While it is never good for a tree to be completely defoliated, early spring defoliation usually results in a second flush of leaves. If the trees were very healthy prior to the infestation, the majority of trees should recover. Trees previously stressed from weather, insect or disease problems will have a harder time maintaining their health. At the very least, it does mean that the trees will be starting off the season in a stressed state. If drought conditions or other stressors occur later this year, some decline and/or mortality will result. Landowners are also reporting bark falling off white oak trees in the western counties. The caterpillars are hiding under loose flaps of bark and birds and squirrels are pulling these off trying to get to the caterpillars. It is only the outer bark, and while unsightly, does not damage the tree. Woodpeckers normally put holes in the trunks causing wounds that attract other insects such as wood borers and decay fungi. If you would like to report defoliation on white oak in counties
not mentioned, please contact the WVDA, Plant Industries Division
at (304)-558-2212. Contact: Buddy Davidson The West Virginia Department of Agriculture protects plant, animal and human health through a variety of scientific, regulatory and consumer protection programs, as mandated by state law. The Commissioner of Agriculture is one of six statewide elected officials in West Virginia. Currently, Commissioner Gus R. Douglass is the longest-serving agriculture commissioner in the nation. For more information, visit www.wvagriculture.org. |
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