Rose Black Spot
Rose black spot, caused by the fungus Diplocarpon rosae, is the most common cause of defoliation of landscape roses in Virginia. The disease is less of a problem in greenhouses where relative humidity can be carefully controlled. Susceptible ... [... more]
Virginia Tech Extension |
Powdery Mildew of Ornamental Plants
Powdery mildew fungi attack a variety of ornamental plants grown in Virginia. Photinia, crape myrtle, dogwood, lilac, Japanese euonymus, wintercreeper euonymus, and many crabapple cultivars are highly susceptible and can be seriously damaged by ... [... more]
Virginia Tech Extension |
Fire Blight of Ornamentals
Fire blight, caused by the bacterium Erwinia amylovora, is a serious disease of many ornamental species in the Rosaceae family. Certain varieties of apple, flowering crabapple, pear, pyracantha, and quince are highly susceptible. Other plants, ... [... more]
Virginia Tech Extension |
Juniper Tip Blights
In Virginia, juniper tip blight is caused by one of two different fungi, Phomopsis juniperovora or Kabatina juniperi. Symptoms of the two diseases are identical; however, some aspects of their control differ. Therefore, correct identification of ... [... more]
Virginia Tech Extension |
Entomosporium Leaf Spot of Photinia
Photinia, a shrub belonging to the rosaceous family, is widely grown in nurseries and landscapes in the eastern United States. Several species, including Photinia serrulata and Photinia glabra, and a hybrid, Photinia x fraseri, are grown for ... [... more]
Virginia Tech Extension |
Powdery Mildew-Resistant Woody Ornamentals
Powdery mildew is a common fungal disease of many ornamental plant species. Although plants are not often killed by the disease, they may become unsightly when heavy fungal growth develops on leaves and flowers. Controlling the disease on ... [... more]
Virginia Tech Extension |
Phytophthora Root Rot of Rhododendron and Azalea
Wilt and root rot of rhododendron and azalea are symptoms of a disease caused by the soil-inhabiting water mold fungus Phytophthora. Several different spe of Phytophthora have been reported to cause similar symptoms, but Phytophthora cinnamomi ... [... more]
Virginia Tech Extension |
Azalea Leaf and Flower Gall
Azalea leaf and flower gall is a disease that causes concern to many Virginia home gardeners each year. It is caused by the fungus Exobasidium vaccinii. In home landscape plantings, the disease is more alarming than damaging, but in greenhouse ... [... more]
Virginia Tech Extension |
Crown Gall of Woody Ornamentals
Authors: G. H. Lacy, Professor of Plant Pathology, Department of Plant Pathology, Physiology and Weed Science, Virginia Tech; and Mary Ann Hansen, Extension Plant Pathologist, Department of Plant Pathology, Physiology and Weed Science, Virginia ... [... more]
Virginia Tech Extension |
Black Root Rot of Japanese Holly
Japanese holly (Ilex crenata) is an important evergreen shrub grown in nurseries and landscapes in Virginia. It is widely used in foundation plantings, hedges, and in mass plantings. In 1976 the disease, black root rot, caused by the fungus ... [... more]
Virginia Tech Extension |
A Guide to Successful Pruning: Pruning Basics and Tools
Pruning is a regular part of plant maintenance involving the Another response to pruning occurs inside plants. around wounded areas, walling off or compartmentalizing the wounds. The branch collar is the swollen area of trunk tissue that forms ... [... more]
Virginia Tech Extension |
Boxwood Leafminer
Now is a good time to scout for boxwood leafminer damage and determine if control is needed on your boxwoods this spring. Boxwood is the only known host for this small fly; American boxwood is the most commonly attacked, European boxwood is less ... [... more]
Virginia Tech Extension |
