Phytophthora Leaf and Twig Blight

You'll see leaf and twig blight as browning and dieback of foliage and small branches. This wet-weather disease spreads by water-splash spores. Remove infected material promptly. Improve drainage and air circulation through selective pruning. Avoid overhead watering and reduce leaf wetness. Plant in well-drained locations. This blight is most damaging during cool, wet springs when flower and shoot development is rapid. Monitor plants closely during vulnerable periods.

Control weeds and brambles to help air circulation. Select a site that permits good air drainage. Remove affected tissue promptly, cutting into healthy wood. Improve air circulation by thinning dense growth and avoid overhead watering during susceptible periods. Preventive fungicide applications may help where the problem recurs annually.