I'm having the same problem w/ my blackberry vines that I had two years ago. Last year's production was great (114 pints from 2 vines). This year and two years ago the canes have shown some pest/disease pattern. I'm not sure if these canes have crown borer, cane borer (due to the 2-year cycle/pattern), cane blight, or all three of these insects/diseases. The producing canes dry out and die from the tip of the cane. Lateral canes are very sparse if exsistent at all. The canes have blossomed, but production will be sparse. I've been cutting back and removing dead/dried up canes. About 4 of the new canes were destroyed from a rain storm a couple of weeks ago. These canes looked pretty hardy and the storm wasn't that bad, so I'm thinking something could be affecting the cane crowns. From the information my county extension agent has referred me to, the only treatment recommended is removing canes and applying insecticide before blossoms appear. What can I do now?? Just wait the season out?? What can I apply to kill this/these pests/diseases in the canes as well as in the soil??? Any advice would be GREATLY appreciated!