fokidex.blogg.se - Purple tree spider

Very effective fungicides for dogwood powdery mildew control include myclobutanil and propiconazole. For fungicides to be effective, they must be applied as soon as symptoms are noticed. If the disease is severe enough to warrant the use of fungicides, be sure that the dogwood is a valuable specimen and the spray equipment can provide good coverage. sericea) is very susceptible to powdery mildew. ‘Cherokee Brave’, ‘Springtime’, and ‘Pygmy’ have partial resistance. The flowering dogwood ( Cornus florida) cultivars ‘Appalachian Joy’, ‘Appalachian Blush ‘, ‘Appalachian Snow’, and ‘Appalachian Mist’ are very resistant to powdery mildew. Cultivars of the oriental dogwood Cornus kousa (such as ‘Milky Way’, ‘Milky Way Select’, and ‘National’) and many of the Cornus florida x Cornus kousa hybrids (such as ‘Aurora’, ‘Constellation’, ‘Celestial’, and ‘Stellar Pink’) are generally resistant to powdery mildew. Resistant species and cultivars are available and should be considered for new plantings. Improve air circulation and sunlight penetration around the tree by removing overhanging branches and crowding vegetation. Prune out dead and infected branches and twigs. Begin by raking up and destroying all fallen leaves. Infection that begins early in the season can be devastating and may warrant the use of fungicides.Ĭultural controls should be the first line of defense. Prevention & Treatment: Most powdery mildews of landscape trees occur late in the summer and are therefore of little consequence. Warm, dry days and cool, damp nights favor disease development. Powdery mildew is most common in dense, shady areas where the air circulation is poor. Spores are spread by wind to surrounding dogwood plants.

Infected leaves exhibit marginal leaf scorch, dead patches, reddish discoloration, yellowing, and premature defoliation. New growth is covered with a fine, white, powdery coating, typically on the upper leaf surface. Powdery Mildew: Erysiphe pulchra (formerly Microsphaera pulchra) is the fungus that attacks leaf surfaces and tender shoots and causes powdery mildew.