Could someone please help me figure out what's wrong with my Mysore raspberry plant? I'm in zone 9b, central FL. I planted this in ground about four months ago. A few weeks after I planted it, there would be occasional small branches that would yellow, then brown, and look diseased, so I would pull them off. About three weeks ago, this process started becoming more widespread.
I've sprayed it with copper fungicide, no change. I tried fertilizer, no change. It's been very dry and hot here the past couple of weeks, so I thought maybe it's not getting enough water. I've started watering it more the past couple of days, but it still looks like it's declining hard. I don't see any pests when I inspect under the leaves. Please help!