Early Bunch Stem Necrosis? - A New Vineyard Malady!
For the past three years we have been in search of the cause for extensive bloom shatter and almost total loss of crop in our Merlot vineyard. We are happy to say that we finally have found the cause for this, as well as a solution. This phenomenon of extensive bloom shatter and loss of fruit set is termed "Early Bunch Stem Necrosis". What it means is that when the vine is in bloom its internal ammonia (nitrogen) level is so high that it actually creates a toxicity which causes the vine to abort it's own unopened flowers. It is actually caused by budding for too small a crop!
In order to avoid this toxicity, we are leaving at least 60% more buds on the Merlot vine in our cropping. These extra buds help to disburse the excess nitrogen, allowing for a normal fruit set. Many may argue that overcropping leads to a reduction in fruit quality. This is not an issue, as once the fruit has set we will thin to desired levels for maximum fruit quality.
Note: In our Harvest Newsletter we were happy to say that our experiments involving multiple kicker canes proved to be a great success, and we were able to avoid Early Bunch Stem Necrosis and bring in a healthy crop of Merlot.