Pseudomonas Blossom Blast and Dieback
Pseudomonas syringae
4 host plants
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Pseudomonas causes blossom blast and shoot dieback on flowers and young shoots in spring. This bacterial disease spreads in cool, wet weather. Remove infected tissue promptly. Improve air circulation around plants. Avoid overhead watering and apply copper fungicides preventively during vulnerable periods. Monitor your plants closely and implement integrated management strategies. Prompt removal of infected material helps limit disease spread.
Protect from frost using a variety of methods including overhead irrigation or wind machines. Prune Asian pear cultivars in summer.
Quick Reference
Management
Bloom period is the primary infection window for blossom blast. Dormant season for bark canker development and dormant-bud death. Severe on wood of 'Old Home' and Asian pear cultivars. Severe blossom blight on 'Packham's Triumph', 'Bartlett', 'Eldorado', 'Anjou', and 'Bosc'. Less severe on 'Comice', 'Forelle', red 'Anjou', and red 'Bartlett'." # Source: PNW Plant Disease Management Handbook (Pear - Pseudomonas Blossom Blast and Dieback)
Rain and low temperatures, especially frost-inducing temperatures during bloom, increase incidence of blossom infection. P. syringae produces ice nucleation proteins that promote frost damage at 28-25°F, creating wounds for bacterial entry. Cool wet spring weather favors disease spread and canker development on woody tissue." # Source: PNW Plant Disease Management Handbook (Pear - Pseudomonas Blossom Blast and Dieback)
Cultural Controls
- Protect from frost using a variety of methods including overhead irrigation or wind machines.
- Prune Asian pear cultivars in summer.
- Remove and destroy infected tissue.