Phytophthora Blight

You'll see phytophthora blight as sudden browning and dieback of shoots and foliage on susceptible plants. Avoid wounding plants, as wounds provide ideal infection sites. This water-loving pathogen spreads in wet conditions. Improve drainage and reduce overhead watering. Remove infected shoots immediately and thin canopies to improve air circulation. This blight is most damaging during cool, wet springs when flower and shoot development is rapid. Monitor plants closely during vulnerable periods.

Remove blighted tissue promptly, cutting well below visible symptoms. Improve air circulation by thinning dense growth. Avoid overhead watering, especially during bloom and new growth periods when tissues are most susceptible. For recurring problems, preventive fungicide applications timed to protect new growth can reduce infection, but cultural controls should be your first approach.