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Bacterial Leaf Scorch of Landscape Trees
Bacterial leaf scorch is an important and often lethal disease of many landscape trees, particularly in the southern and eastern U.S. In Virginia landscapes it is most often observed on oak, elm, and sycamore; however, many other landscape tree species are susceptible to this disease. The bacterium that causes bacterial leaf scorch colonizes the tree's water-conducting tissue (xylem), disrupting water movement and reducing water availability to the tree. The symptoms of bacterial leaf scorch are very similar to symptoms of other problems that limit water uptake. This is why marginal leaf scorch symptoms caused by other problems, such as drought stress or root disease, are often mistaken for symptoms of bacterial leaf scorch. Laboratory identification of the causal bacterium (Xylella fastidiosa) from affected petiole and leaf tissue is necessary for positive confirmation of the disease.
Feb 2, 2024 3001-1433 (SPES-568NP)
Anthracnose - A Fungal Disease of Shade Trees
Anthracnose is a generic term for a disease that occurs on many ornamental and forest trees. A number of different fungi cause anthracnose on various hosts. It occurs most commonly and severely on sycamore, white oak, elm, dogwood, and maple. Other host plants that usually show only minor symptoms of anthracnose include linden (basswood), tulip tree, hickory, birch, and walnut. Anthracnose fungi may be host-specific, as in the case of sycamore anthracnose, which infects only sycamore and not other tree species. Anthracnose fungi have similar life cycles, but require slightly different moisture and temperature conditions for infection.
Feb 26, 2024 450-604 (SPES-555P)
Black Root Rot of Holly
Black root rot is a fungal root disease that is a serious and extremely common problem on Japanese holly (Ilex crenata), a commonly used evergreen landscape shrub. Inkberry holly (Ilex glabra), blue or Meserve holly (Ilex crenata) are also very susceptible to black root. The disease is not as commonly diagnosed on blue holly and inkberry holly as on Japanese holly in the Virginia Tech Plant Disease Clinic. The black root rot pathogen is soil-borne and can be introduced into a landscape on infected nursery plants. Chinese holly (Ilex cornuta) and English holly (Ilex aquifolium), are resistant to the black root rot pathogen.
Feb 7, 2024 450-606 (SPES-569P)
Verticillium Wilt of Shade Trees
Verticillium wilt is a serious vascular wilt disease affecting many shade tree species and over 80 tree genera, as well as many woody ornamental landscape plants, and herbaceous and vegetable plants. Verticillium wilt most commonly occurs in nursery, orchard and landscape locations. Maple (Acer spp.) are a tree genus commonly associated with the disease, but Verticillium wilt occurs on many other trees and woody ornamentals used in landscapes. Verticillium wilt more commonly occurs in locations with colder climates than Virginia; however, Verticillium wilt does cause disease on trees and woody ornamentals in Virginia.
Feb 29, 2024 450-619 (SPES-571NP)
Rose Rosette Disease
Rose rosette disease (RRD) is a serious disease problem of cultivated roses, and over the past two decades RRD has become the most important rose disease in North America. RRD is caused by Rose rosette virus (RRV). RRD leads to stunting, decline and death of roses, yet there are no easy, economical or particularly effective management tactics for RRD. Currently, the major rose cultivars available to growers are susceptible to RRD.
Dec 20, 2023 450-620 (SPES-556P)
Brown Rot on Peach and Other Stone Fruits
Brown rot is one of the most destructive diseases of peach and nectarine in Virginia, and also occurs on other stone fruits such as apricot, cherry, and plum. When environmental conditions favor this disease, crop loss can be devastating.
Feb 16, 2024 450-721 (SPES-554P)
Reducing Pesticide Use in the Home Lawn and Garden
Pesticide use affects the quality of human health, the environment, and nontarget organisms in the ecosystem. Therefore, any pesticide application warrants a careful assessment of the expected benefits and risks. Too often, however, homeowners use pesticides inappropriately or without careful consideration of alternatives. This fact sheet outlines general pest control tactics that can easily be implemented for home lawns and gardens, along with other information that home owners can use to make sound pest management decisions. The intent is to ensure that homeowners are aware of alternative control tactics and pesticide characteristics, and that pesticides are used properly and only when necessary
Mar 18, 2024 450-725 (SPES-589P)
Botryosphaeria Canker and Dieback of Trees and Shrubs in the Landscape
Most trees and shrubs are susceptible to dieback and cankers caused by several species of the fungal genus Botryosphaeria. Botryosphaeria fungi are typically opportunistic pathogens. Opportunistic pathogens only cause disease on plants that are stressed. Therefore, avoiding plant stress, which predisposes plant tissue to infection and colonization by this fungal group, is the best strategy to prevent Botryosphaeria disease problems.
Nov 17, 2023 450-726 (SPES-527P)
Late Blight of Tomato and Potato Jan 19, 2024 ANR-6 (SPES-567P)
Best Management Practices for Boxwood Blight in the Virginia Home Landscape
Boxwood blight is a devastating disease of boxwood that results in defoliation and decline of susceptible boxwood. This best management practices factsheet provides guidelines for home growers of landscape boxwood to avoid introduction of the boxwood blight pathogen into a landscape or, if the disease is already present in a landscape, to manage to disease in the most effective manner and avoid spread of the disease to new locations.
Dec 19, 2023 PPWS-29NP (SPES-557NP)
Plant Injury From Herbicide Residue
Herbicides that are usually associated with contamination of straw/hay, turf clippings, manure, and composts are growth regulator herbicides or synthetic auxins, a group of herbicides that mimics plant hormones and regulates growth. These herbicides are labeled for control of broadleaf weeds in grass crops, such as pastures and corn; in turfgrass, including lawns, golf courses, parks, and highway turf; and in noncrop areas. Vegetable and fruit crops, as well as broadleaf ornamentals can inadvertently be injured by these chemicals through drift of spray droplets, volatilization, and spray tank contamination or by residues in straw, manure, turf clippings, or compost. Diagnosing the specific herbicide responsible for the plant damage can be difficult. This publication focuses on damage caused by herbicide residues.
PPWS-77P (SPES-565P)
Vascular Streak Dieback: An Emerging Problem on Woody Ornamentals in the U.S. Feb 28, 2024 SPES-483P (SPES-587P)