Notes on Raspberry Diseases
Late leaf rust
Identification
Small yellow spots and masses of yellow powdery spores develop on the
leaf underside. Badly infected leaves drop prematurely; canes with severe
defoliation are more susceptible to winter injury. Orange-yellow patches
of rust also develop on flower parts and fruit, which make the fruit unmarketable.
Late leaf rust symptoms on raspberry
Period of Activity
White spruce is the alternate host for this disease and it produces spores
that can travel for many miles in the air. In July, spores from white
spruce cause the first infections on flowers, calyces and leaves of fruiting
laterals. These first lesions produce new infections on leaves and fruit
throughout the growing season. Most serious symptoms are noticed in late
summer. Fruit infections can be quite serious on susceptible fall-bearing
cultivars.
Management notes
Heritage and Festival are very susceptible. Nova is highly resistant
to this disease.
White spruce is a host for this disease. Removal of white spruce in the
vicinity of the planting may help reduce the potential for disease on
raspberry. Keep rows narrow and control weeds to improve drying in the
row.
Learn more...
