The health of Maryland’s hemlocks, and the associated ecosystems, is being threatened by the hemlock woolly adelgid (HWA). This small, exotic insect is native to Asia, and was first found in North America in British Columbia in the1920’s. It was reported in Richmond, Virginia in 1951, and spread northward into Maryland by the 1980’s. Landscape [...]
Fall webworms are slightly more than 1 inch long and covered with long, pale, gray hairs. The body color ranges from yellow to brown with dusky, mottled areas along the sides and two rows of black dots along the back. Most characteristic of the fall webworm are the large, silk webs that encircle the ends [...]
Verticillium is common in many soils and affects several hundred herbaceous and woody plant species, while exhibiting definite host preferences. Verticillium can become a serious problem on susceptible hosts in infested soils, since the fungus persists in the soil indefinitely, many times on hosts that exhibit no symptoms. Because of its ability to spread internally [...]
The eastern tent caterpillar, Malacosoma americanum, is a pest native to North America. Populations fluctuate from year to year, with outbreaks occurring every several years. Defoliation of trees, building of unsightly silken nests in trees, and wandering tent caterpillars crawling over plants, walkways, and roads cause this insect to be a pest in the late [...]
Spider mites are common pest problems on many plants around yards and gardens. Injury is caused as they feed, bruising the cells with their small, whip like mouthparts and ingesting the sap. Damaged areas typically appear marked with many small, light flecks, giving the plant a somewhat speckled appearance. Following severe infestations of spider mites, [...]
Scale insects can be serious pests on trees, shrubs, and other perennials. Most people don’t recognize them as a scale insect because most immature (nymphs) are immobile, wingless, and lack a separate head or other recognizable body parts.
Plant rust is a general term that refers to a rather large family of fungi that attack plants. Frequently, when a plant is affected by rust fungi, many gardeners feel at a loss as to what to do. Rust treatment as a plant disease is startling but can be treated. Rust fungi are very easy [...]
Root rot is a general term that describes any disease where the pathogen (causalorganism) attacks and leads to the deterioration of a plant’s root system. Most plants are susceptible to root rot, including both woody and herbaceous ornamentals. Root rots can be chronic diseases or, more commonly, are acute and can lead to the death [...]
Powdery mildew, as the name implies, often appears as a superficial white or gray powdery growth of fungus over the surface of leaves, stems, flowers, or fruit of affected plants. These patches may enlarge until they cover the entire leaf on one or both sides. Young foliage and shoots may be particularly susceptible. Leaf curling [...]
The peach tree borer is a native North American pest that causes serious damage to peach, cherry, plum, nectarine, and apricot. Damage is caused by the larval stage, primarily to younger trees. Larvae tunnel into the roots and lower trunks of the hosts feeding on the growing tissue and inner bark. Young trees may be [...]
