See:
Peach (Prunus persica) - Leaf Curl
Cause Taphrina populina and T. populi-salicis, fungi, have been reported from Oregon and Washington but only the latter from Idaho. Life cycle is similar to that of peach leaf curl. Often found on Lombardy poplar growing west of the Cascade Range. These fungi live saprophytically in a yeast-like phase, overwintering on dormant bark and buds. Spores infect young leaves before the cuticle hardens.
Symptoms Irregular, convex blisters develop on upper leaf surfaces following cool, wet spring weather. A bright golden yellow "bloom" may appear on the concave undersurface of the affected leaf part; later it turns brown. Early stages can be confused with leaf rust.
Cultural control We lack research data on controlling leaf blister in Oregon. However, the principles used to control peach leaf curl or cherry witches' broom may be useful.
Chemical control Spray just before bud break.
- Bonide Fung-onil Multi-purpose Fungicide at 2.25 teaspoons/gal water. Group M5 fungicide. H
- Daconil Weather Stik at 1.38 pints/100 gal water. Group M5 fungicide. 12-hr reentry.
- Rex Lime Sulfur Solution (28%) at 6 to 12 gal/100 gal water. 48-hr reentry. O
Reference Newcombe, G. 2005. Genes for parasite-specific, nonhost resistance in Populus. Phytopathology 95:779-783.