Resources by Mary Ann Hansen

Title Available As Summary Date ID Author
Problem-free Shrubs for Virginia Landscapes
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.
Jun 27, 2016 450-236 (PPWS-69P)
Problem-free Trees for Virginia Landscapes
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.
Oct 19, 2016 450-237 (PPWS-70P)
Iris Leaf Spot
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.
Nov 1, 2016 450-600 (PPWS-90NP)
Juniper Tip Blights Mar 30, 2017 450-601 (PPWS-91 NP)
Botrytis Blight of Peony
Botrytis blight is a common fungal disease that confronts the peony grower each spring. The fungus Botrytis cinerea blights stems, buds, and leaves and can cause plants to look unsightly, especially in wet springs. This fungus causes disease on a wide variety of herbaceous and woody ornamentals, as well as vegetables and small fruits. It is sometimes referred to as “gray mold” because of the conspicuous, fluffy, gray fungal growth that forms on infected plant parts.
Sep 26, 2016 450-602 (PPWS-93NP)
Powdery Mildew of Ornamental Plants
Powdery mildew fungi attack a variety of ornamental plants grown in Virginia.
May 1, 2009 450-603
Leaf and Flower Gall of Azalea and Camellia
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.
Oct 18, 2016 450-605 (PPWS-92NP)
Entomosporium Leaf Spot of Photinia
Photinia, a shrub belonging to the plant family Rosaceae, is a popular landscape shrub in the southeastern U.S. Several species are grown, but the most popular is the hybrid Photinia ×fraseri, or “redtip”, so named for its bright red, immature foliage. The biggest drawback to growing photinia is a leaf spot disease caused by the fungus Diplocarpon mespili (syn. Entomosporium mespili) to which redtip is highly susceptible.
Sep 30, 2016 450-609 (PPWS-82P)
Rose Rosette Disease
Rose rosette disease (RRD), a disease believed to be caused by the recently identified Rose rosette virus, has been spreading through much of the wild rose population of the Midwestern, Southern, and Eastern United States for years.
Sep 17, 2012 450-620 (PPWS-10P)
Corn Smut
Common smut of corn is caused by the fungus Ustilago maydis. The fungus causes gall formation on all aboveground parts of corn plant
May 1, 2009 450-706
Impatiens Downy Mildew May 21, 2013 PPWS-19NP
Best Management Practices for Boxwood Blight in the Virginia Home Landscape: Version 2, September 2016
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.
Sep 30, 2016 PPWS-29NP (PPWS-85NP)
Virginia Boxwood Blight Task Force
To provide leadership in safeguarding and protecting the ornamental horticulture industry, historical gardens and landscape plantings from boxwood blight.
May 20, 2014 PPWS-30
Best Management Practices for Boxwood Blight: Best management practices for boxwood blight in Virginia production nurseries WITH boxwood blight Version 2, September 2016
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.
Sep 30, 2016 PPWS-32NP (PPWS-87NP)
Best Management Practices for Boxwood Blight in Virginia Production Nurseries WITHOUT Boxwood Blight Version 2, September 2016
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.
Sep 30, 2016 PPWS-33NP (PPWS-86NP)
Best Management Practices for Boxwood Blight: Best management practices for Virginia retail nurseries WITH boxwood blight Version 2, August 2016
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.
Sep 30, 2016 PPWS-34NP (PPWS-89NP)
Best Management Practices for Boxwood Blight: Best management practices for Virginia retail nurseries WITHOUT boxwood blight Version 2, September 2016
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.
Sep 30, 2016 PPWS-35NP (PPWS-88NP)
Best Management Practices for Boxwood Blight for Greenery Producers
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.
Oct 13, 2016 PPWS-39NP (PPWS-95NP)
Boxwood Blight: A New Disease of Boxwood Found in the Eastern U.S. Jan 5, 2012 PPWS-4
Best Management Practices for Boxwood Blight for Professionally Managed Landscapes and Public and Historic Gardens in Virginia
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.
Sep 26, 2016 PPWS-49NP (PPWS-84NP)
Plant Injury From Herbicide Residue
In recent years, an increased number of cases of injury from herbicide residue in straw/hay, manure, and compost have been diagnosed in the Virginia Tech Plant Disease Clinic. Growers are surprised and dismayed to learn that manure, straw, mulch, or other amendments intended to improve their garden or landscape might have such unforeseen consequences. Of particular concern to organic growers are herbicide residues.
Aug 22, 2016 PPWS-77P