In the Vineyard

An out-of-control vineyard, pre-bloom. This vineyard could have benefited from more buds left at pruning and then remove extra shoots at fruit set to bring the canopy into balance and open it up for light

penetration and air flow.


Why spray? It’s a key part of good housekeeping Left without protection early in the spring, a vineyard can decline into a disastrousmildew infection by late summer.

few secondary infections such as botrytis and sour rot and it can make a person really wish vineyard cleanup and early season spray had been done.

By Gary Strachan E

veryone knows that the two most important factors that predispose a vineyard to a mildew infection are moisture and temperature. Add some old infected prunings, some mummified fruit, and tender, young, unprotected shoots in spring, and you have the recipe for black, blotchy canes next fall. Good housekeeping to remove infected material will go a long way toward protecting a vineyard by eliminating most of the mildew spores floating around on those lovely spring breezes.

They’re insidious. The initial infection of the tender new shoots won’t be visible until the canes start to harden later in the summer, but an invisible secondary release of spores can happen quickly, as soon as the weather warms up to the mid 20s. If left without protection early in the spring, a vineyard can decline into a disastrous mildew infection by late summer, and it will be too late to do anything about it. Add to this a

30 British Columbia FRUIT GROWER • Spring 2017

What’s early season? It’s almost tradition that a dormant spray of lime-sulfur be applied before budbreak. There’s a risk of damaging the new buds if you’re late, so use a lighter application if buds are swollen or open. A spray of dormant oil is also a good way to inhibit mites and

leafhoppers by smothering eggs. It makes a sticky mess, but you can combine the the two. After the buds break and the weather warms, it’s time for your first spray, whether you use organic or systemics. The new shoots are vulnerable at this point; green and tender and growing rapidly. At about 7 centimetres (3 inches) the shoots require their first protection. Systemic sprays protect new growth for a longer duration at this period of development. A surface

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