I have a patch of black and purple raspberries: five Bristol, two (remaining) Jewel, three Glencoe, 2 Cumberland, 1 Royalty, and 1 Brandywine.
Something seems to be killing off my Jewel plants in particular within about 2 yrs of planting. I get one good crop year, then they peter out. Bristol seems unaffected so far as do Glencoe and Brandywine purples. Cumberland and Royalty seem moderately affected but none have per se died yet.
I’ll post a pic below, but basically, the fruiting floricanes do OK, but the primocanes start off fine and vigorous, then suddenly the new growth gets “weak” and the cane eventually dies entirely by early August. That’s how it happened last year on a Jewel plant, and in 2021 on an original Jewel plant I bought in 2019. The plant I thought died last summer did attempt to push some weak primocanes this spring, but they petered out.
This year, a different Jewel plant, which grew fine last summer and fine this year until a couple weeks ago, is showing this same phenomenon on 2 of the 5 primocanes it is pushing. I don’t know for sure that it’s dying like the other one did, but it has that same look the other plant did before slowly dying off last year.
My Royalty purple seems to be very stunted this year as well, and my Cumberland blacks (2 plants total) are kinda in-between - not quite as bad as the affected Jewel plants, but not really as vigorous as last season. My other Jewel plant (which is a year younger and came from a different nursery source) looks fine and is still growing like gangbusters. So far my Brandywine plant is also unaffected. I will note the Jewel plant exhibiting this phenomenon is a tip-root off the original plant that died, as is the one that died last season. The unaffected one is one I purchased separately.
What is odd is that Jewel is constantly touted as more disease resistant than Bristol, but for me Bristol is the winner, and so far, does not seem affected by this phenomenon.
What is this? Is it viral? Anthracnose? Verticillium wilt? Cane borer? Is there anything I can do?