Pre-Pruning in the Vineyard: Disease Prevention and Vine Life Extension
If you’ve cruised up to wine country in the last couple weeks, you’ll notice vineyards are looking fairly bare. The shoots on the vine are either unpruned and naked of all their leaves or have been cut down to a 2-bud stub on the cordon, but what about those vines that look like they’ve been half pruned, with canes only about a foot long?
Lately, a new trend has started to develop involving two passes through the vineyard. The first pass typically occurs anywhere between October and December and trims canes down to about 12 inches. It’s being called ‘double’ or ‘pre-‘pruning and has been most commonly practiced, so far, on cordon-pruned vineyards. It can even be mechanized, potentially saving cost and time! Whether done by hand or machine
Vines re-pruned to 12 inches is advantageous in a couple ways:
– Prunes canes down to a manageable length, i.e. No shoots in your face for the final prune, explained below
-Lowers risk of fungal spores landing on the vulnerable final cut and traveling down into the rootstock, potentially doing some major damage to the vine
Keep in mind, it’s not uncommon for fully developed shoots to reach six feet in length. Often these shoots hang over the top wire, getting in the way of precision cuts during pruning. The angle and length of the final prune is crucial for the success of the vine during the next growing season. When there are several old shoots hanging in your face and poking your eyeballs, it’s difficult to make the best cut.
More importantly, during the vine’s dormant time, winter, is when fungal spores can attack and potentially cause a major infection called Eutypa lata. The spores love to stick to the raindrops that land on the vines and it’s the perfect place for them to make their home. By the time these spores can potentially climb down the canes, it’s time for another prune and the part of the affected cane is trimmed off. Preventing disease now can extend the life of the vine.
About where the cut is being made in the below picture is where the pre-prune cut will be, taking the vineyard through to the end of winter.
When the weather turns toward spring is when it’s best to make the final cut, which will look like the vines below. There will be less cane to work with so crews can focus on the cut itself, the angle and number of buds. During the warm and dry weather is when the open cuts can heal quickly, if the sap hasn’t already started to flow. Either way, spores have much less of an opportunity to infect, and give vines the best foundation for a healthy start to the growing season.