Some of northern VA growers contacted us about splitting of the trunks and cordons which became apparent in the last few weeks. Although the cold injury model showed that temperature we experienced were below the threshold temperature (i.e., the buds should be safe in many cases), the cold winter then a few days of warmth followed by another cold temperature probably caused some of vines to show more or less like "Southwest injury" on trunks and cordons.
If you have these suffering vines, you would probably think about re-training damaged cordon or trunk. If you decided to do, please keep in your mind that the big wound can invite various vascular/trunk pathogens such as Esca and Botryosphaeria. These disease may not damage the vines in a short time, but it can shorten the life of the vine.
As I noted in my trunk disease management page, there are few options to provide protections on these wounds.
The bottom line is that you should pick a day without rain in the forecast and provide a protection (Topsin-M, Rally, even Dreft, or B-lock (new paint material), please see the trunk disease management page for more details). B-lock is a latex paint with Boron, and the previous studies showed the efficacy against Esca and Eutypa dieback. If you cannot find B-lock in nearby co-op or chemical distributors, you can find them at
Farm Supply Company, they are in CA, but they will ship to VA.
(B-lock applied trunk)
Also, if you are interested in helping me on data collection, I have a small supply of B-lock that I would like to test out in a field experiment.
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