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Resources by Mary Ann Hansen

Title Available As Summary Date ID Author
Integrated Pest Management for Vegetable Gardens Sep 12, 2019 426-708 (ENTO-330NP)
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, 2022 450-236 (PPWS-69P)
Arbustos ideales para los paisajes de Virginia (Problem-free Shrubs for Virginia Landscapes)
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.
Aug 7, 2023 450-236s (SPES-429s)
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.
Jun 29, 2022 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 2, 2021 450-600 (PPWS-90NP)
Juniper Tip Blights Mar 30, 2017 450-601 (PPWS-91 NP)
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)
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)
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)
Angular Leaf Spot of Cucumber
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.
Jan 22, 2024 450-700 (SPES-528P)
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)
Virginia Boxwood Blight Task Force
To provide leadership in safeguarding and protecting the ornamental horticulture industry, historical gardens and landscape plantings from boxwood blight.
Jul 1, 2019 PPWS-30
Best Management Practices for Boxwood Blight in Virginia Production Nurseries WITH 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.
Feb 16, 2021 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.
Jan 5, 2021 PPWS-33NP (PPWS-86NP)
Best Management Practices for Boxwood Blight: Best Management Practices for Virginia Retail Nurseries WITH 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.
Jan 6, 2021 PPWS-34NP (PPWS-89NP)
Best Management Practices for Boxwood Blight: Best management Practices for Virginia Retail Nurseries WITHOUT 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.
Jan 6, 2021 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.
Jan 6, 2021 PPWS-39NP (PPWS-95NP)
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)
Mortality of Great Rhododendron (Rhododendron maximum) in Virginia
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.
Aug 21, 2019 SPES-151P
An Overview of Southern Blight, Caused by Sclerotium rolfsii Aug 24, 2021 SPES-325NP
Anaerobic Soil Disinfestation for Management of Soilborne Pests in Vegetables Jul 6, 2021 SPES-326NP
Arbustos ideales para los paisajes de Virginia (Problem-free Shrubs for Virginia Landscapes) Dec 5, 2022 SPES-429P