I read that you shouldn't put black raspberries next to reds because reds carry a virus that can knock out the blacks (after I planted some 2 years prior)

Anybody know how common this virus is?

Also, the black variety seem to be the kind that grows and grows (quite different fro the red which seem to stop at about 5-6 feet. What's the best way to trellis or control these longer ones. Just start bending them around in a gradual circle?

While I'm at it, I heard ealier that raspberries wont prodcue berries on a cane that has produced berries already, but this year I see some dried out berries from last year, and what looks like developing flowers/buds on the same cane !?!

Scott