Upright Dieback
Diaporthe vaccinii (asexual: Phomopsis vaccinii)
13 host plants · Fungal
Last updated
This profile contains verified disease data from extension databases. Regional field notes and expert review are in progress.
Blueberry flowers, twigs, and shoots die back with elongated cankers at stem bases, showing red-flagging of leaves. Diaporthe vaccinii infection occurs during wet spring bloom. Prune during dry periods and thin flower spurs. Remove dead branches. Fungicides like captan may help during extended wet conditions, though preventive practices are paramount.
Remove affected material as you find it and clean up any fallen debris where upright dieback spores can overwinter. Improve air circulation around susceptible plants through selective pruning. Avoid overhead irrigation during vulnerable growth periods. If the problem is persistent, your local Extension office can recommend current fungicide or bactericide options for your specific situation.
Quick Reference
Management
Spring (April-May) during new shoot emergence and active growth. Peak: late April through May. Upright/terminal growth most vulnerable.
Cool wet spring (50-62°F) with 10+ hours continuous leaf wetness. Rain-splash dispersal. Plant stress exacerbates severity.
Cultural Controls
- Prune Asian pears during dry periods in the winter, or delay pruning until spring or summer. Summer pruning also helps slow down overly vigorous trees. Thinning flower spurs during dry periods reduces bloom, helps improve fruit size, and may reduce the amount of disease observed. Avoid planting Asian pears in frost pockets or low-lying areas. Do no