Fusarium wilt is a common and lethal disease of mimosa (Albizia julibrissin)1, also commonly known as silktree. In the United States this disease occurs in the east from New York southward and also in Louisiana, Arkansas and California. Fusarium wilt is caused by the fungus Fusarium oxysporum forma specialis perniciosum. Albizia spp. are the only known host of F. oxysporum'' f.sp. ''perniciosum''. Fusarium oxysporum f. sp. perniciosum colonizes and clogs the tree’s vascular (water-conducting) tissue, and interferes with the movement of plant sap. This results in relatively rapid tree death.

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.

No-tillage corn production has been practiced in Virginia for more than 35 years (Jones et al. 1968), yet many producers have not used no-tillage to its maximum advantage. This publication addresses where no-tillage corn can and should be adopted, and where no-tillage production needs to be modified to reduce production problems associated with continuous use.

Plant Disease Diagnostic Form

The Plant Disease Diagnostic Form was designed to accommodate a wide variety of plants and growing situations; therefore, certain entries on this form may not be appropriate for a particular specimen or situation. Much of the information requested helps reconstruct the "field situation" for the diagnostician. Consider each section of the form carefully; the information provides important clues to the diagnostician that are significant in guiding the diagnostic process and formulating the control recommendation. Your local Extension office staff can assist you in completing the form and include the relevant information requested on the form, so when possible, complete the form with the assistance of your local VCE agent or VCE staff member.

The most effective form of plant disease control in the landscape is prevention. Disease prevention can be as simple as choosing the right plant for the right place at planting time. This fact sheet was developed as a guide to shrubs that generally experience few problems in Virginia landscapes. Using these species for new plantings should help you avoid troublesome disease and insect problems in your landscape.

La forma más eficaz de controlar las enfermedades de los cultivos en nuestro jardín es la prevención. La prevención de enfermedades puede ser tan sencilla como elegir el cultivo adecuado para el lugar adecuado al momento de cultivar. Esta hoja informativa fue desarrollada como una guía de los arbustos que generalmente experimentan pocos problemas en los paisajes de Virginia. El uso de estas especies para las nuevas plantaciones debería ayudarle a evitar problemas de enfermedades e insectos en su jardín.

Many of the tree species commonly planted in Virginia landscapes suffer from disease problems. Although some diseases can be cured, most must be controlled on a preventative basis. The best option for new plantings is to choose species that have a low risk of developing disease. Listed below, in alphabetical order, are some choices of problem-free trees for Virginia landscapes.

Iris leaf spot (also called Heterosporium leaf spot) is the most common disease of iris in Virginia. It is caused by the fungus Cladosporium iridis (syn. Heterosporium iridis). Leaf spotting is most conspicuous on the upper half of the leaf following bloom. Although this pathogen is most common on bulbous iris, it can also cause severe damage to rhizomatous iris, and has also been reported on Gladiolus, Freesia and Narcissus species.

Powdery mildew fungi attack a variety of ornamental plants grown in Virginia.

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.

Leaf and flower gall is a disease that is common on azaleas and camellias in the spring. The disease has also been reported on other members of the plant family Ericaceae. It occurs in home landscapes and nurseries, and is often seen on flame azaleas in the forest in the spring. The disease is caused by species of the fungus Exobasidium.

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.

This publication attempts to distinguish the symptoms of these four major diseases of dogwood.

English boxwood, are susceptible to several diseases that can decrease their effectiveness in established plantings. The major diseases of boxwood are discussed

Wilt and root rot of rhododendron and azalea are symptoms of a disease caused by the soil-inhabiting water mold fungus Phytophthora.

Sooty molds of trees and shrubs commonly occur throughout Virginia on conifers, hardwoods, and other plant species

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.

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.

Angular leaf spot of cucurbits is caused by the bacterium Pseudomonas syringae pv. lachrymans. The bacterium can attack a wide range of cucurbits including watermelon, melon, squash, cucumber, zucchini, and pumpkin.

Bacterial spot, caused by the bacterium Xanthomonas campestris pv. vesicatoria, is one of the most serious diseases of sweet peppers in Virginia.

Common smut of corn is caused by the fungus Ustilago maydis. The fungus causes gall formation on all aboveground parts of corn plant

Early blight, caused by the fungus Alternaria solani, is one of the most common diseases of tomatoes in Virginia.

Anthracnose is a major disease of the common snap bean (Phaseolus vulgaris) and can occur on other legumes. It is caused by the fungus Colletotrichum lindemuthianum. When environmental conditions are favorable, crop losses can be as high as 100 percent on susceptible cultivars of snap beans.

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.

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

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.

The mighty American chestnut tree (Castanea dentata [Marsh], Borkh.) was once a dominant figure in hardwood forests throughout the eastern United States. An iconic source of food, chestnuts were sold by the ton every year, until the chestnut blight nearly brought this tree crop to extinction in the early to mid-20th century.

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.

To provide leadership in safeguarding and protecting the ornamental horticulture industry, historical gardens and landscape plantings from boxwood blight.

This Best Management Practice document is a set of 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 the disease in the most effective manner and avoid spread of the disease to new locations.

This Best Management Practice document is a set of 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 the disease in the most effective manner and avoid spread of the disease to new locations.

This Best Management Practice document is a set of 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 the disease in the most effective manner and avoid spread of the disease to new locations.

This Best Management Practice document is a set of 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 the disease in the most effective manner and avoid spread of the disease to new locations.

Best management practices for boxwood blight (also called “box blight”) for greenery producers are practices recommended to avoid the introduction and spread of boxwood blight, caused by the fungus Calonectria pseudonaviculata (syn. Cylindrocladium pseudonaviculatum). The recommendations in this document are designed to avoid spread of boxwood blight within a planting or to new locations when pruned tips are collected, sold and/or used for holiday greenery1. These recommendations are relevant to anyone involved in the greenery (“tipping”) industry, including small and large-scale greenery producers, home growers who sell boxwood tips, and people who tip-prune boxwood on other people’s property. Care must be taken at all levels of greenery production to prevent the spread of the boxwood blight pathogen and avoid economic losses associated with this disease.

Boxwood blight is caused by the fungal pathogen Calonectria pseudonaviculata (syn. Cylindrocladium buxicola). Boxwood blight was first described in the United Kingdom in the mid-1990’s and by 2002 was found in several other European countries and New Zealand. In September 2011 boxwood blight was discovered in North America. Symptoms of the disease include leaf spotting (Fig. 1), elongate, dark cankers on stems (Fig. 2), defoliation, and dieback (Fig. 3). The primary means by which the disease spreads is the inadvertent introduction of infected boxwood to existing plantings. The pathogen can also spread by spores, which readily adhere to equipment and work clothes, and by microsclerotia, which survive in infested soil and plant debris. This document outlines best management practices for landscapers and property managers to reduce the risk of spreading boxwood blight to landscapes and public and historic gardens, and to manage the disease if it is introduced.

This is a guide for understanding the biology of plant nematodes, how they affect different crops, how to sample for them, how to interpret nematode sample results and management strategies.

Since 2015, Extension specialists from Virginia Tech (VT) have visited and collected plant and soil samples from several large areas of dying great rhododendron (Rhododendron maximum) in Virginia’s mountainous regions. In 2016 VT specialists met with Virginia Department of Forestry, US Forest Service personnel, and other experts to revisit some of these sites. No consistent cause of this mortality has yet been identified. It is possible that a variety of factors are stressing the rhododendrons in these areas to a point where opportunistic pathogens or insects can successfully attack and kill them. The following information summarizes our observations and diagnostic results from four separate great rhododendron mortality sites in Virginia. This information is not equivalent to a research study, which would also include samples taken from healthy great rhododendron for comparison; however, we are confident that we have ruled out two diseases that are frequently mentioned both online and anecdotally as a cause of this mortality, specifically Phytophthora root rot and Botryosphaeria dieback.

In this publication, we describe apple blotch disease, also known as Marssonina leaf blotch, an emerging apple disease in the Eastern United States. This disease leads to severe apple tree crown defoliation that indirectly affects the apple fruit size, color, yield and twig development. The causal gent of this disease is a fungus Diplocarpon coronariae (also known as Marssonina coronaria).

Fungal species in the Colletotrichum genus are the causal agents of bitter rot on apples. In Virginia, six Colletotrichum species cause apple bitter rot: C. fructicola, C. chrysophilum, C. siamense and C. theobromicola from CGSC and C. fioriniae and C. nymphaeae from CASC. Over the past two decades, bitter rot infections have been increasing in the Mid-Atlantic region, where these pathogens are becoming more prevalent due to increasingly warm and wet weather conditions that favor Colletotrichum growth. The region produces approximately $500 million worth of a worth of apples every year. Losses to bitter range from 14% to 100% in commercial apple orchards. This publication describes causal pathogens, their biology and management approaches and has practical and scientific significance.

In 2019, a new species of Neopestalotiopsis was reported to cause significant damage in strawberry fields in Florida. Since then, this disease has been found in most southeastern states, including Virginia and Delaware. Molecular identification has revealed that more than one Neopestalotiopsis species is pathogenic to strawberry plants and can cause symptoms on leaves (leaf spot), fruit (fruit rot), and crown (crown rot) of strawberry plants. We would like to share the current knowledge on the biology of Neopestalotiopsis spp. and management practices that could partially suppress Neopestalotiopsis fruit rot in strawberries.