Page 40 - Grapevine Jan-Feb 2020
P. 40
Around The Vineyard
diseases and address pest concerns before they to replace the one-year-old canes annually.
become significant issues. Spur pruning is most often used for high fruitful-
ness varieties and is relatively easy to do. This is
When to Prune the most popular method of pruning among vine-
yards today, particularly for grape varieties like
As a general rule, dormant pruning can be done Merlot and Cabernet Sauvignon.
anytime between leaf drop in the fall and bud
break in the spring. Vineyards around the country Meanwhile, head training is sometimes practiced
may start pruning right after Thanksgiving into by vineyards without trellising. While this practice
mid-December, but this tedious job usually extends is economical, it’s important to watch for rot and
through March. Some vineyards wait until January mildew, as well as congested canopies that can
to begin their dormant pruning because this is topple under their own weight.
when the canes become woody.
“We spur prune the majority of the vineyard
Jordan Lonborg, viticulturist at Tablas Creek because 65% of the vineyard is on trellis,” said
Vineyard in Paso Robles, California, told The Lonborg. “Ten percent of the vineyard is cane
Grapevine Magazine that his vineyard chooses pruned as well. A majority of the cane pruning
when to prune largely based on weather. occurs on Syrah and Viognier due to their vigorous
nature.”
“We typically start pruning in January,” he
said. “But the majority of pruning takes place in Disease Identification and
February and March.” Weeding While Pruning
Vineyards may postpone pruning to assess cold Grapevine diseases can occur at any time of the
injury better and adjust pruning levels to compen- year, but the winter season is a useful time to
sate for losses. Double pruning is sometimes used check plants for abnormalities and take action.
to avoid spring frost injury. However, the availabil- Some of the most common diseases that grape-
ity of labor in the winter months has a big impact vines experience are Pierce’s disease, phylloxera,
on when vineyards do their pruning as well. downy mildew, powdery mildew, gray mold, black
rot and vine truck diseases such as Petri disease
“Pruning your grapes too early in the season is and black measles.
a mistake that novices make that can result in
no fruit production,” Randy Killion, president of While pruning, keep an eye out for discolored
Zenport Industries in Sherwood, Oregon told The lesions that are red, brown or black. Other signs of
Grapevine Magazine. Zenport manufactures and disease are curling leaves, weak or short shoots,
markets professional and consumer specialty horti- rapid wilting and shriveled leaves or grape clusters.
culture tools and supplies for the lawn and garden, Also, look for grapes covered in a gray or tan pow-
landscape, irrigation and agriculture markets. der or leaves with yellow edges.
“If low temperatures and strong winds follow prun-
ing, it’s very possible that the pruned parts will However, a visual diagnosis may not be sufficient,
freeze,” Killion said. “This will make you lose all or and it may require laboratory analysis to identify
part of your crop. Therefore, it’s recommended certain bacterial and fungal diseases correctly. To
that pruning is delayed until February.” protect the healthy plants in the vineyard, prompt-
ly remove diseased wood and either burn it (if your
Types of Pruning area allows burning) or add it to the green waste
bin to be hauled away.
Cane pruning is most commonly used for grape
varieties that have low natural fruitfulness on the Pruning and weeding go hand-in-hand around this
basal buds. This type of pruning requires vineyards time of year, and there are important factors to
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