Water plants around the base of the plant and not over the foliage.Īllow adequate ventilation around the plants, preferably plant them 30cm apart. Photo: ShutterstockĪs box blight thrives in humid conditions, avoid clipping box in wet weather or when rain is forecast in the next few days. Try not to position taller plants over box, because they could drip on them. If you buy box plants for your garden, check them carefully for signs of pest and disease, and quarantine for six weeks before planting. This important, as nurseries may use fungicides that keep blight at bay for a short period. If you buy box in, ensure you quarantine the plants for six weeks to monitor for symptoms. Prevention is better than cure! Propagate new plants from your own healthy box plants and try to keep your plants growing as healthily and robustly as possible, by ensuring they have everything they need in terms of water, sunlight and fertiliser. Contaminated boots and clothing could also bring in the blight’s sticky spores. This is particularly relevant if you employ a mobile gardener. Another way is on tools that have been used on infected plants. The primary route by which box blight could get into your garden is on newly bought plants. Treatments for Cylindrocladium will treat Volutella too, but while good plant nutrition and growing conditions will help reduce Volutella, Cylindrocladium needs more control than this. Volutella needs a cut leaf surface to enter the plant, while Cylindrocladium can enter through the leaf cuticles in humid weather. Remember that box can turn yellow or look sick for lots of reasons, such as a lack of nutrients or because it is growing in too much shade. For Volutella blight, the leaves yellow and darken to a shade of tan.Leaves turning brown or black and dropping off, especially in humid conditions.Brown spots on the surface of the leaves.Symptoms of Cylindrocladium box blight include: The two diseases often appear together but Cylindrocladium is more serious. Confusingly, the term often covers another box disease too, Volutella blight ( Volutella buxi). The origins of box blight ( Cylindrocladium buxicola) are not known but it occurs around the world, from New Zealand to the UK. Check the undersides of leaves for evidence of box blight. Wayne Ellett Plant and Pest Diagnostic Clinic, for confirmation. If box blight is suspected, we urge that you send affected plants to our OSU Extension, C. This highly destructive fungus typically causes a rapid decline of entire plants rather than sectional dieback. "Box blight" caused by the fungus, Cylindrocladium buxicola, should also be eliminated before making a Volutella blight diagnosis. NOTE: boxwood defoliation and dieback may also be caused by a number of other problems including salt damage, winter injury, boxwood leafminer, and various root rots. Of course, sanitation pruning may significantly disfigure heavily infected plants. The disease may be managed by pruning a few inches beneath the transition zone. A careful removal of the bark will expose chocolate colored phloem tissue with a distinct transition zone between dead stem tissue and healthy green tissue. A close examination of the affected stems may reveal loose bark and constricting girdling. Leaves turn light yellow then brown and eventually drop from infected stems. Symptoms first appear in the spring and intensify with new growth. The fungus targets stems where it produces girdling infections. Sectional Foliar Discoloration from Volutella Canker on Boxwoods Both English and American boxwoods are susceptible to this disease which is caused by the fungal pathogen, Pseudonectria buxi (also called Volutella buxi). One candidate for the sectional dieback is Volutella blight. Landscapers and gardeners may be seeing scattered dieback on boxwoods this spring.
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