FAIRFAX COUNTY, Va. – A newly emerging disease called Vascular Streak Dieback has been killing nursery stock and new plantings purchased from nurseries throughout Virginia and in at least five other states. As County residents begin buying trees and shrubs for fall plantings, the Urban Forest Management Division is advising them to be on alert for the disease. Dieback may look like yellowing or paling of the leaves’ green color (leaf chlorosis), brown or scorched leaf margins and stunting and/or wilting of current year’s growth. In Virginia, redbud (Cercis canadensis), maple (Acer spp.), and dogwood (Cornus florida) appear to be the most affected.
Scientists studying VSD have consistently found a fungus Ceratobasidium theobromae (synonym: Rhizoctonia theobromae) inside the woody stem of trees in nurseries showing symptoms of dieback. This fungus already has been reported as the cause of VSD on cacao in Southeast Asia. The study from 2012 found VSD spreading by wind carried fungal spores in cacao plants. After a spore infects a leaf, it travels into the branch and the main stem’s woody tissue, eventually killing the plant. Researchers continue to study VSD, and the fungus related to it, to find ways to prevent infection and the potential spread into the natural environment.
Virgina Cooperative Extension recommends that nurseries ensure best management practices of plant stock to prevent chances of infection. Residents looking for trees in nurseries may consider asking nursery staff about vascular streak dieback and if the internal woody tissue may safely be checked for VSD before purchasing. Also, look for any signs of scorched leaves and buds or dieback of young stems. If VSD is suspected in a recent purchase report it to the Virginia Cooperative Extension and dispose of the plant material correctly to prevent its potential spread. Plants, or the suspected live branches, also may be bagged and either taken or mailed to the Extension, where the disease can be positively identified. If mailing, a two-day delivery is best to avoid damage to live tissue.
Find more information on identifying and reporting VSD here Vascular Streak Dieback: An Emerging Problem on Woody Ornamentals in the U.S..
Virginia Tech Extension Fairfax Office
12011 Government Center Parkway
Fairfax, Virginia 22035
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Directions on mailing samples to the Plant Disease Clinic: Helpful Tips for Submitting Adequate Samples to the Plant Disease Clinic.
Plant Disease Clinic
106 Price Hall
170 Drillfield Drive Virginia Tech
Blacksburg, VA 24061-0331