2024 Grapes Table of Contents: 7.7 Equipment for Weed Control in Vineyards

Page Contents

7.7 Equipment for Weed Control in Vineyards

7.7.1 Boom Applicators
7.7.2 Sensor-Controlled Applicators
7.7.3 Controlled Droplet Applicators (CDA)
7.7.4 Flame Applicators
7.7.5 Where to buy Equipment and Nozzles

7.7 Equipment for Weed Control in Vineyards

Herbicides require good application techniques if improved deposition and drift reduction is to occur. Some of the commonly used herbicides can damage vines so great care must be taken. Drift has been a major concern for some years, off target movement wastes money, reduces deposition on the target plant, damages vines, can lead to pesticide residue on grapes, pollutes water, and may cause strain with other people.

44090

7.7.1 Boom Applicators

Two main types of boom applicators are available. A frame can straddle over the top of the canopy, spraying under the vine on each side of the target row. The other type may be fitted to the front of the tractor spraying one side only of the adjacent row. 20-30 gallons per acre are typical spray volumes.

The use of hoods and break-back devices are important. A hood will protect the vines from drift of small droplets being emitted from a conventional flat fan nozzle. A break-back device will protect the sprayer boom and nozzle from damage caused by inadvertently striking a post or trunk.

44091

7.7.2 Sensor-Controlled Applicators

Sensor-controlled pesticide applicators use optical sensors to determine where weeds are located. These sensors, coupled with a computer controller, regulate the spray nozzles and apply herbicides only when needed, thus considerably reducing herbicide use. A computer-controlled sensor detects chlorophyll in plants and then sends a signal to the appropriate spray nozzle, applying the herbicide directly to the weed. The operator calibrates the system to bare soil or pavement, allowing the computer to determine when a weed is present. Sensor-controlled applicators are often mounted on ATVs or UTVs. Typically, this type of applicator can be used at speeds up to 10 mph. A complete sensor-controlled system consists of a chemical tank, pump, battery power, computer controller, optical sensors and spray nozzles.

Benefits of sensor-controlled applicators include:

Reduced amount of herbicide applied.
Reduced potential for groundwater contamination.
Ability to apply herbicides in dark or light conditions.
If equipped with wind-deflecting shields, can reduce herbicide drift.

44092

7.7.3 Controlled Droplet Applicators (CDA)

A CDA herbicide applicator is an electrically driven spinning disc under a large plastic hood or dome. The outer edge of the disc has small teeth which break up the liquid herbicide into droplets, 95% of which are the same size. The speed of the spinning disc determines droplet size. As there are no large or small droplets in the CDA spectrum, all droplets stick to the plant, allowing for rates as low as 1 to 8 GPAto be applied.

Various widths of hoods or domes can be selected and are fitted with break-back devices. Where the ground is rough, e a bristle skirt maybe used. Where applications are made around young vines, an optional plastic cover can be fitted over the bristle skirt.

CDA sprayers reduce the amount of water required, thus considerably improving spraying logistics. They are lightweight, relatively inexpensive, and very maneuverable.

44093

7.7.4 Flame Applicators

Flame applicators simply use a flame to destroy weeds. Most flame applicators burn liquid propane gas to create a flame having a temperature near 2000F. The flame is applied directly to the weeds using a hand-held wand or with boom-mounted torches attached to a tractor or ATV. The flame is applied to the weed for only a short period of time, usually about 1/10 of a second. The length of time the flame is applied depends on the age, size and tenderness of the weed. When the weeds are exposed to the flame, the water inside the plant cells boil, causing them to burst. (The weeds are not burned up.) By destroying the plant cells, the plant is unable to transport water and continue photosynthesis, causing the weed to wilt and die.

It is recommended that the flame be applied to weeds when they are 1 to 3 inches tall and typically in the spring and early summer. Flame applicators should only be used when there is little or no potential for setting fire to dry plant material. Beware of setting fire to trellis posts and poison ivy.

Benefits of flame applicators -