The most important spray of the season for control of anthracnose on brambles is the delayed dormant spray of lime sulfur, Sulforix or copper hydroxide. Delayed dormant is when buds are fully expanded and new leaves are exposed about a half inch. If you have a problem with anthracnose, this is one spray that you can’t afford to miss. In my experience anthracnose is mainly a problem on black raspberries. Most modern cultivars of blackberries and nearly all red raspberries are resistant. That said, delayed dormant applications can reduce overwintering inoculum of a number of important pathogens.
Black raspberry at 1/4 inch green
Apache blackberry at early swell. Note small spider visiting
Heritage red raspberry at 1/4 inch green