Raspberry leaf spot is perhaps the most common raspberry disease we see in the clinic. Early infections look like dark green circular spots on new leaves. As leaves get older, spots become light tan to gray (see picture below). Severe infections cause leaves to fall off in late summer and early fall and this may not only reduce your raspberry harvest, but it also makes plants more prone to winter injury.
Infected raspberry leaves showing gray-tan spots caused by S. rubi.
Infected raspberry leaves with raspberry leaf spot. Lesions may fall out creating a shot-hole appearance.
S. rubi spores produced in lesions are spread by rain and wind-driven rains to young tissues.
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