Ramorum Leaf Blight

Ramorum causes leaf blight and stem cankers on various hosts, with symptoms appearing during cool, wet springs. Remove infected leaves and branches. Improve air circulation and reduce leaf wetness. Avoid overhead watering. Monitor for symptoms and remove infected plants if disease is severe. 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.