Virginia Evergreen Winter 2018

VCTGA News Journal ‒ Winter 2018 VCTGA News Journal – Winter 2018  is an unfortunate reality that box- wood blight can be spread by spores and microsclerotia and these propa- gules can be carried on and by almost anything between sites if they are not washed and sanitized. Hoses are a good example of a tool that might be overlooked as a potential carrier. I cannot over emphasize to folks the importance of sanitation when work- ing with boxwood in landscapes. Folks need to wash and sanitize all tools and equipment, hoses, boots, anything that touches boxwood or touches the ground around boxwood during landscape maintenance be- tween sites. Remember; once the dis- ease is spread to a site we have found it is very hard to eradicate. Even traces of inoculum can result in se- vere disease expression during wet years due to repeating disease cycles. Boxwood are used in a variety of ways in the landscape. We see that compact shrubs of the ‘American’ and ‘English’ boxwood and some re- lated hybrids are very prone to devel- oping severe defoliation from box- wood blight due to their compact crowns. Plants in the shade are also more prone to developing severe de- foliation. Much of this relates to mi- crosite and leaf wetness period. We have yet to see what boxwood blight may have in store for larger speci- mens of ‘American boxwood’ at Vir- ginia’s historical sites which can have stems with diameters 6 inches and greater. The most severe defolia- tion we have observed is in the lower crowns of boxwood. One theory is larger diameter specimens in which the lower crowns have been pruned by man or nature may allow these older specimens to maintain healthy upper crowns due to more airflow and drier microsite higher up off the ground. A lot remains to be seen. I am very hopeful that over time we will adapt to this disease; keeping older specimens around when deemed ap- propriate, redesigning gardens to re- duce leaf wetness periods, applying

 Landscape contractors should at all times be equipped with a san- itation “kit” for disinfesting tools and equipment and take precau- tions to avoid moving spores on clothing, boots, hoses, vehicles, etc. Specific recommendations for effective sanitation methods are detailed on the Virginia Box- wood Blight Task Force website (under the “Sanitizers” tab).  Landscape companies should en- sure their staff are familiar with the symptoms of boxwood blight so that they can recognize the disease in the landscape. Lami- nated wallet cards with images of symptoms of boxwood blight and information on the Virginia Box- wood Blight Task Force website are available through your local Virginia Cooperative Extension office. Resources: the Virginia Boxwood Blight Task Force website and Best Management Practices Refer to the Virginia Boxwood Blight Task Force website for further information on boxwood blight. We recom- mend that you familiarize your- self with the appropriate Best Management Practice (BMP) for your situation. The BMPs are available on the website as PDFs. From: Virginia Boxwood Blight Task Force Date: Tips - Only you can help prevent boxwood blight! It is that time of year where we begin hearing about and discovering box- wood blight expressing itself on plants in nurseries and landscapes. Already a few cases at retail nurseries this fall associated with nursery stock shipped in from out of state. One newer twist for 2017 is Virginia Tech Cooperative Extension is re- porting cases in the landscape where the disease was likely spread by pruning tools and other equipment. It

 If boxwood blight is suspected, immediately contact your local Extension office, which can sub- mit a sample for confirmatory di- agnosis. Where boxwood blight is confirmed, it is strongly rec- ommended to immediately re- move and double bag all diseased plants and fallen leaves as well as contaminated soil underneath the planting. The bagged waste should be removed to a desig- nated landfill to mitigate disease spread to other boxwood in the landscape and other properties nearby. • Employ only landscape professionals who are aware of how boxwood blight spreads, since boxwood blight can be in- troduced to properties through landscape maintenance activi- ties. The fungal spores and fallen diseased leaves can be moved on tools, boots, tarps, hoses, cloth- ing and vehicles. Landscape pro- fessionals should have a stringent sanitation plan in place to decon- taminate tools, equipment, vehi- cles, clothing, shoes, etc. be- tween landscape locations and other practices that minimize the chance to move the disease through landscaping activities. • Adhere to best management practices outlined for boxwood blight, which are detailed in PDFs available at the Virginia Boxwood Blight Task Force website. Additional Precautions for Landscape Professionals:  Landscape professionals are strongly advised to walk through a site before beginning work. This is to identify any potential boxwood blight problems and/or risks. We have heard anecdotal reports from landscape profes- sionals of both serious equipment contamination issues and spread of the disease by unexpected en- counters of the disease in a land- scape.

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