Spider Mites (Tetranychus urticae)
Tetranychus urticae (an animal with over 60 common names, including red spider mite and two-spotted spider mite) is one of many species of plant-feeding mites found in dry environments, and generally considered a pest. It is the most widely known member of the family Tetranychidae or Spider mites.
T. urticae is extremely small, barely visible with the naked eye as reddish or greenish spots on leaves and stems; the adults measure about 0.5 mm. The red spider mite, which can be seen in greenhouses and tropical and temperate zones spinning a fine web on and under leaves. The red spider mite is extremely polyphagous; it can feed on hundreds of plants, including most vegetables and food crops (peppers, tomatoes, potatoes, beans, corn, strawberries) and ornamentals: roses, etc. It lays its eggs on the leaves, and it poses a threat to host plants by sucking cell contents from the leaves cell by cell, leaving very tiny, pale spots or scars where the green epidermal cells have been destroyed. Although the individual lesions are very small, commensurate with the small size of the mites, the frequently-observed attack of hundreds or thousands of spider mites can cause thousands of lesions and thus can significantly reduce the photosynthetic capability of plants, greatly reducing their production of nutrients, sometimes even killing the plants. Although this way of feeding could spread plant viruses, this is considered of secondary importance.
Woolly Adelgid (Adelges tsugae)
The Woolly Adelgid (Adelges tsugae) is a native of Japan and was first reported in the eastern United States in 1951 near Richmond, Virginia. By 2005, the insect was established in portions of 16 states from Maine to Georgia, and infestations now cover about half of the hemlock’s range.
It is in the family Adelgidae, which is related to aphids. The Adelgid uses long mouthparts to extract sap and nutrients from hemlock foliage, this prevents free growth, causing needles to discolor from deep green to grayish green, and to drop prematurely. The loss of new shoots and needles seriously impairs tree health. Infestation is usually fatal to the host after several years. Valued plantings of the shade-loving Eastern hemlock (Tsuga canadensis) can be ravaged by the Wooly Adelgid, and the natural stands of hemlock in the forests and parks would be greatly affected if the pest spreads to those locations. The wind, birds, other wildlife and the movement of infested host material by humans are all factors in the dispersion of the adelgid. Currently all WV counties are infested with the Wooly Adelgid.
Gypsy Moth (Lymantria dispar)
Gypsy moth larvae generally prefer oaks, but may feed on several hundred different species of trees and shrubs, both hardwood and conifer.
In the East the gypsy moth prefers oaks, aspen, apples, sweetgum, speckled alder, basswood, gray and paper birch, poplars, willows, and hawthorns, although other species are also affected. The list of hosts will undoubtedly expand as the insect spreads south and west.
The gypsy moth avoids ash trees, tulip-tree, American sycamore, butternut, black walnut, catalpa, flowering dogwood, balsam fir, arborvitae, American holly, and shrubs such as mountain laurel and rhododendrons, but will feed on these in late instars when densities are extremely high. Older larvae feed on several species of hardwood that younger larvae avoid, including cottonwood, hemlock, Atlantic white cypress, and the pines and spruces native to the East.
Emerald Ash Borer (Agrilus planipennis or Agrilus marcopoli))
The average length for an adult emerald ash borer is ¾ in (20 mm) long and 1/6 in (4 mm) wide. The larvae are approximately 1 mm long and .6 in (15 mm) in diameter, and are a creamy white color. The color of the larvae make them very difficult to spot on a tree. The eggs turn to a yellow brown color prior to hatching.[1] The average emerging season for the emerald ash borer is early spring to late summer. Females lay around 75 eggs from early May to mid-July. The feedings are usually finished by fall. The EAB's life cycle is estimated to be one year in southern Michigan but may be up to two years in colder regions.
In October 2007, an emerald ash borer larva was discovered in a West Virginia Department of Agriculture "detection tree" located in Fayette County. This detection tree was located in a recreational site, with camping, mountain biking, and white water rafting. It is believed that the pest arrived in firewood that was illegally transported by tourists visiting the New River Gorge area, a popular site for white water rafting.
