Coryneum blight (Shothole)
Wilsonomyces carpophilus
38 host plants · Fungal
Last updated
Shothole is a fungal disease typically attacking the leaves of ornamental (flowering) cherries. Lesions are initially dark brown, reddish, or purplish spots and may be surrounded by a light green to yellowish halo.
Start with sanitation: remove and dispose of affected material as you find it. Thin dense growth to improve air circulation, and redirect irrigation away from foliage. If the condition persists despite cultural adjustments, your local Extension office can help identify the pathogen and recommend targeted treatments.
What Should I Do?
- Prune and destroy dead buds and cankered twigs
- Rake and destroy infected fallen leaves
- Avoid overhead watering
Quick Reference
Management
Spring bud break through early summer; any time leaves or flowers are wet
Moisture on leaf or flower surfaces for 24+ hours; temperatures above 36F (2C). At 77F (25C), infection requires only 6 hours of wetness." # source: "Wikipedia (Shot hole disease)
Cultural Controls
- Prune and destroy dead buds and cankered twigs WSU HortSense
- Rake and destroy infected fallen leaves WSU HortSense
- Avoid overhead watering WSU HortSense
- Space plantings and prune for good air circulation WSU HortSense
- Remove and dispose of infected buds, leaves, fruit, and twigs Wikipedia
Common on ornamental flowering cherries and English laurel (cherry laurel) throughout Western Washington residential landscapes. Favored by the cool, wet spring conditions typical of the maritime climate, with prolonged leaf wetness during the infection window. Sweetheart cherries are particularly susceptible in western Oregon and likely western Washington. Several peach cultivars are not suitable for western Washington due to persistent shothole pressure in the maritime climate. Fall application of copper at leaf drop is especially important due to heavy autumn rains." # source: "PNW Plant Disease Management Handbook