Growers Reminded To Watch Out For Grape Pruning Disease

Grapevine pruning diseases can be extremely harmful in established grapevines, occurring after the vines are pruned back after the growing season. Dr. Akif Eskalen, plant pathology, Cooperative Extension Specialist and lecturer in the Department of Plant Pathology at the University of California, Davis, has done extensive research on the causes, prevention and treatment of grapevine pruning diseases.

“Grapevine pruning diseases are one of the most important challenges for viticulture that affect the vineyard longevity and productivity in all grape vine varieties, wine grape, table and raisins, not only in California but also worldwide. The main entry point for these pathogens are the pruning wounds that all grape growers have to do during the dormant season. That’s why it’s very important that should be prevented before the disease gets into the plant.”

Eskalen noted grapevine pruning diseases are common, as they can affect other woody plants.

“These group of pathogens are very common pathogens, not only colonizing or attacking grapevines, but other woody plants. Because of that, they have a very wide variety of hosts. When it comes to the monoculture that we have to do in our agriculture in today, that also gives them a good opportunity to find good suitable hosts next to each other to colonize and cause diseases.”

Growers he pointed out have few options to prevent grapevine pruning diseases.

“Late pruning practices become an option for our grape growers. and another practice, known as double pruning, but the problem with that is that you have to do the pruning right before the bud break, that will give you a short time of application of those pruning wounds and pruning of the grapevine, which also brings a shortage of time and labor shortage, but these are the options that grape growers have been applying.”

SePRO Ag offers Bio-Tam, a biological product that contains Trichoderma, to help prevent grape pruning diseases.

“Trichoderma species are known to suppress pathogens by either direct competition for the nutrition or space on the pruning wound. Trichoderma-based products are able to colonize the pruning wounds, producing a lot of secondary metabolites that protect the pruning wounds from the fungal pathogens. Sealants, however, are another well-known pruning wound protectant. The only difference that I could see is that the sealants doesn’t have the fungicidal effect, they may not be as effective as the biological for controlling the diseases.”

Bio-Tam has two separate strains of Trichoderma and should be applied immediately after pruning.

“Bio-Tam has two different strains of Trichoderma to protect the pruning wounds, combining and working together. When it comes to the application time, Trichoderma-based products could be applied during the dormant season, which is the winter. All of fungi prefer the higher temperature to colonize, but they are also able to colonize in the lower temperature, as well. So I can see that biocontrol agents may have this kind of advantage.”

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