Spray Set-Ups for Viticulture

When it comes to spraying, grape growers must defend their vines on two main fronts. Pests and diseases abound and are fought with a variety of pesticides. Weeds are the other enemy and must be countered with herbicides.

Universal vineyard pests include a large range of mites, moths, borers and weevils, while some common diseases found in grape vines include black rot, powdery mildew and cane and leaf spot.

Common set-ups for canopy spraying of pesticides in vineyards include air blast sprayers (either low profile or tower), air shear sprayers and rotary atomiser sprayers.

Air blast sprayers apply low to medium volumes, using droplets sized between 30 and 350 microns. These droplets are directed by the fan’s air stream onto the plant. Air blast sprayers displace the air around the plant with the air from the sprayer.

The size of the droplets is controlled by the nozzles used and the operating pressure. The normal type of nozzle employed with air blast sprayers is hollow cone. Those that produce larger droplets are arranged at the top and those producing smaller droplets are placed at the bottom.

Air shear low volume spraying is a method that ensures constant droplet size and thus maximum chemical concentration. It is a system that delivers fast, high volume, uniform coverage with less run-off.

Rotary atomiser sprayers are sprayers with a high speed rotating disk or cup, which throws off droplets as the spray flows onto it. The size of the droplets is governed by the speed of the disk’s rotation.

Regardless of which spraying set-up is used, correct calibration is vital for accurate application. After determining your sprayer’s travel speed using the test-run method (plotting out a course and timing your travel across it), application rate can then be calculated using the formula; litres per minute (per side) = recommended litres per hectare x kilometres per hour x space between rows ¸ 60,000.

Grape vines generally require spray treatment with insecticides, fungicides, nutrients and growth regulators, all applied at different stages in the plant’s life cycle. Consequently, spraying equipment must be recalibrated for each type of application.

Your spray equipment should also be checked regularly for wear (filter, nozzle, ball valve etc) and worn parts replaced as necessary. Nozzle wear is the most frequent and depends on the material it is made from, the type of chemicals being used and the operating pressure of the sprayer.

Herbicides used to control weeds in a vineyard are usually applied using a boom spray set-up. The most common application method is to create a weed-free strip along the rows of vines.

The application of herbicides to reduce weeds is preferable to cultivation methods, as it causes less erosion and no damage to plant roots.

As with pest management, calibration of boom sprayers for weed control is essential for accurate application. Regular service of boom spray spray equipment is also necessary, particularly hoses and pumps. Australia has excellent spray equipment service agents in every state and territory.

When applying herbicides, great care must be taken, as some chemicals used to control broad-leaved weeds can cause significant damage to vines. Always be aware of adjacent crops and don’t spray if weather conditions are not favourable.

Pest and weed management in viticulture is a relatively straightforward process, as long as you understand the kinds of enemies you are up against, the critical periods for dealing with them, the right chemical mixes to use, and the correct methods of application.

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