05-Oct-09 10:04 | Eric Stafne

Wow, I’ve never seen a situation like that!  A clearly good blackberry grower who has a big-time problem on his hands due to viruses.  Nearly 100% of the plants were infected.  How does that happen?  The most likely answer is that the plants were already infected with the viruses at the nursery and then manifested when enviromental conditions were right (cool conditions).  What can the grower do now?  Well, he has two options — continue to crop the plants until they decline past the point of profitability or pull them out and replace them.  The first option is the most viable in this case.

Unfortunately, many grape growers are in the same situation.  Viruses tend not to kill plants, but rather predispose them to other problems.  When buying plants try to get vines that are virus indexed (this does not mean virus free, no one can claim virus free as viruses are difficult to detect and many exist outside of what is usually tested for).  Be on a lookout in your vineyard for viruses.  The most common one is Leafroll virus with typical symtoms showing up in July/August with reddening of the leaves and downward rolling of the leaves.  Fruit may also take longer to ripen.