Raspberry leaf spot

[1][2] Although they are also grown in the Midwest and northeastern states, the output is not nearly as great due to the colder weathers and shorter growing seasons.

[1] S. rubi prefers warmer and wetter conditions, which can make raspberry production very difficult in California.

More severe infections can cause leaves to drop prematurely in the late summer and early fall.

However, Demaree and Wilcox demonstrated the raspberry pathogen could not cause leaf spots on blackberry or dewberry.

Once infected, the raspberry leaf serves as a nutrient source for the fungus to begin producing secondary inoculum, or conidia, within pycnidia, a survival structure that protects the spores.

When the leaves of the raspberry plant begin to fall, perithecia form in the fallen tissue where asci and ascospores will be produced and protected until the following spring.

Raspberry leaf spot infections will typically be more severe in parts of the United States that are climatically warmer and more humid.

Less pesticide and fungicide can encourage biological control agents, reduce production costs, and minimize the chemical residues in fruit.

[1][9][10] Cultural practices are also important for the management of raspberry leaf spot, this includes spacing out and narrowing rows to increase air flow and faster drying as well as removing any weeds and thinning out old canes.

Sanitation, which includes the removal of all plant debris and infected canes in the fall, reduces places for the pathogen to overwinter.

[6] If defoliation does occur due to raspberry leaf spot, the outcome can be economically devastating for the farmer.