Hi there! It's hard to tell from just pictures but it looks to me like it might be a nutritional deficiency. I'd recommend applying a complete fertilizer soon and then again in the spring. Cheyenne

Thank you for your answer. What kind of picture would help you better diagnose the problem?

Things like this are hard to diagnose with just a picture in general. Ideally I'd see the whole cane, with pictures of both the top and underside of young and old leaves that look healthy and unhealthy as well as close ups of the fruits and any lesions on the leaves. If you want a for sure diagnosis you could send it in to the plant and pest diagnostic lab on campus. If you'd like to talk more about your raspberry plant feel free to email me directly at <personal data hidden>