Since vascular streak dieback of some commonly grown nursery ornamentals has become a concern for many growers, it is important to be aware of new releases of information about this issue. Currently several University diagnostic clinics such as those at Purdue University and NC State University have confirmed vascular steak dieback on the following species:

• Eastern Redbud (Cercis canadensis)
• Flowering dogwood (Cornus florida)
• Black gum (Nyssa sylvatica)
• Wax myrtle (Myrica cerifera)
• Southern catalpa (Catalpa bignonioides)
• Northern catalpa (Catalpa speciosa)
• Sweetshrub (Calycanthus floridus)
• Spicebush (Lindera benzoin)
• Umbrella magnolia (Magnolia tripetala)
• Green hawthorn (Crataegus viridis)
• Chinese plum (Prunus salicina)
• Red maple (Acer rubrum)
• Feeman’s maple (Acer x freemanii)
• Witch hazel (Hamamelis virginiana)
• Paperbark maple (Acer griseum)
• Serviceberry (Amelanchier canadensis)
• Kousa dogwood (Cornus kousa)
• Witch-alder (Fothergilla spp.)
• Tulip poplar (Liriodendron tulipifera)
• Fragrant sumac (Rhus aromatica)
• Giant tree lilac (Syringa reticulata)

According to Mike Munster at the NC State University Plant Disease and Insect Clinic, Cercis canadensis is by far the most common species affected, distantly followed by Cornus florida, and maples (Acer spp.) are possibly third most affected.

Recently Virginia Cooperative Extension released a new online fact sheet titled Vascular Streak Dieback: An Emerging Problem on Woody Ornamentals in the U.S.  This publication contains information about the current situation, symptoms, what we know and don’t know, avoidance, management, and lab diagnosis. It does list some information about fungicides. However, keep in mind that the potential causal disease species for vascular streak dieback has not been scientifically confirmed and thus no fungicide trials have been conducted, so there are no current official recommendations for management or prevention with fungicides.