Crop and Pest Management Guidelines

7.12 Spraying Small Vineyards

On many small-scale vineyards, spraying often requires special attention to selecting the correct sprayer, calibration, calculating amounts of pesticide to use, and accurately measuring pesticide products.

To ensure even distribution throughout the canopy, a systematic approach to spraying the whole canopy is essential. Take particular care to cover the top of the canopy as well as ensuring adequate penetration into the inside and middle of the canopy and the fruiting zone. Spray from both sides of the row. Water sensitive cards (Syngenta) or kaolin clay may be used to check spray distribution.

7.12.1 Selecting a Small Sprayer for the Small Vineyard

There are many important points to consider before purchasing a sprayer, not the least of which is the area to spray, the proximity of the local supplier, standard of manufacture, etc. There are many growers with small vineyards who don't require airblast sprayers and have a need for spraying equipment ranging from backpack sprayers to small truck- or ATV-mounted machines.

Canopy Sprayers

Backpack sprayers. Small capacity (4-5 gallon) sprayers will produce up to approximately 100 psi pressure. Weight is an important consideration and growers should select a sprayer with good, wide, padded straps to ease the load on your shoulders. Correct nozzle selection according to the target is very important to ensure even coverage. A good-sized filling hole at the top is also important.

There are three factors affecting application rate - forward speed, pressure, and nozzle tip size. Unfortunately, most inexpensive backpack sprayers have no pressure gauge. Pay more money and purchase a backpack sprayer with a pressure gauge or, better still, purchase a spray management valve as standard equipment or as an option. Normally output increases or decreases according to the pressure in the system, (which depends on how vigorous you pump the handle up and down). A spray management valve, such as a CF valve, ensures a constant output regardless of hand pump action.

An alternative to the hand-operated backpack sprayer is an electrically-operated backpack sprayer, which utilizes a small rechargeable battery. Maximum pressure is relatively low and it is easier than using a traditional hand pump system, particularly if you have many rows of vines to spray. Similarly, a small backpack sprayer fitted with a small gas engine is available. The electric version is quieter to use, but you must remember to recharge the batteries.

Portable mist and air blower backpacks. These are ideal for vineyards where canopy penetration is required such as with denser, less manicured canopies. A small gas engine drives a fan blower that creates an airstream through a hand-held tube (similar to a leaf blower). The tube has a nozzle at the end that sprays liquid into the airstream. The operator points the hand-held tube towards the canopy to disperse the spray. To reduce pesticide exposure, point the tube backwards to avoid walking into the spray. Reducing engine speed lowers airspeed for smaller canopies in early season. They are very good at rustling the canopy helping withspray penetration and deposition. However, they are heavy and noise is a problem so hearing protection must be worn.

Portable engine-driven gas sprayers. If weight is a problem and ground conditions are relatively smooth, a number of manufacturers offer a sprayer with a small gas engine and a 10- to 12-gallon tank. Larger capacity tanks (14 to 100 gallons) are often trailed and can be pulled by a lawn tractor, ATV, or small tractor.

Small, mounted sprayers. Ideal for mounting onto the carrier rack of an ATV, these sprayers are typically 15 to 25 gallons and use a small electric pump to provide up to 70 psi pressure. When used with a hand wand and a hose, they can be used to spray short lengths of vine rows. The same system is ideal for weed control and spot spraying of weeds.

Large, skid mounted sprayers. Ideal for the back of a pick-up truck, these sprayers have a tank capacity of 35 to 200 gallons and an electric-start gas engine.

Small, trailed airblast sprayers. Very small airblast sprayers, with tank capacities up to 110 gallons and a 5.5 to 20 hp gas engine, can be towed by an ATV or a small tractor. Larger tank capacities up to 300 gallons are also available but require larger tractors with weights and brakes for safe operation. Remember, the larger the gas engine, the more important it is to buy an electric start option. Small airblast sprayers are ideal in smaller vineyards but suffer from a lack of air direction. Therefore, purchase sprayers with deflectors or towers to direct the air into the canopy.

Small, mounted airblast sprayers. Three-point hitch, PTO-driven models with a 22- or 24-inch fan that can be mounted onto 25 plus horsepower tractors are available. Beware of drift so consider models which direct the air via deflectors or towers.

Herbicide or Ground Application Sprayers

Backpack, small ATV-mounted tank, and hand-lance sprayers. These sprayers can be used for herbicide application BUT be very careful if you use them to apply other types of pesticides. Be sure to wash them thoroughly between uses so that there are no herbicide residues in the sprayer. Ideally, you should have a dedicated sprayer for herbicides to reduce chances of carry-over.

Controlled Droplet Applicators (CDA). The use of CDA's will considerably reduce the need to carry vast amounts of water. A spinning disc (battery powered) will produce 95% of the same-size droplets, thus reducing herbicide rates by at least 50% and water rates by 75%. Herbi and Mantis (trade names) are both hand-held CDA sprayers. ATV- or tractor-mounted shielded CDA sprayers, such as the Enviromist, also reduce spray rates while shielding the vines from the spray.

Wick wipers. Where occasional weeds and access over wet land are a problem, the use of a hand-held wick wiper is an easy-to use, effective option. A small tank, usually contained in the handle, holds the liquid, which soaks a rope wick or a sponge. The rope or sponge can then be wiped against the weeds.

7.12.2 Calibrating Small Sprayers

Calibration of Backpack Sprayers - in General

Use clean water

DYNAMIC CALIBRATION

• Select correct nozzle and pressure.
• Measure and mark off an area 10 feet x 10 feet on concrete.
• Fill sprayer to a known level, mark the fill level.
• Spray the area on the concrete.
• Refill sprayer to the fill mark.
• Compare quantity collected with nozzle chart and desired amount.

STATIC CALIBRATION

• Select correct nozzle and pressure.
• Measure and mark off an area 10 feet x 10 feet on concrete.
• Spray the area and record time taken.
• Carry out stationary run of same time duration, catching liquid in a graduated measuring jug.
• Compare quantity collected with nozzle chart and desired amount.

Calibration of Backpack Sprayers - for Canopy Spraying

• Fill the spray tank with a known quantity of clean water (e.g. 2 gallons)
• Determine the number of vines that you can spray on both sides with the spray tank (e.g. 48 vines covered)
• Determine the total number of vines per acre (e.g. 968 vines per acre)
• Calculate the spray volume required per acre:

Spray volume/acre = (vines per acre ÷ vines covered per spray tank) x volume applied in spray tank

e.g Spray volume/acre = (968 ÷ 48) x 2 = 40 gallons per acre

7.12.3 Calculating the Amount of Pesticide to Use

Many pesticides are typically sold for large-scale vineyards and give application rates on a per acre basis or an amount per 100 gallons of spray mix. When converting a known quantity per acre to spray a smaller area, the first step is to measure the area to be sprayed using a tape measure. Divide the number of square feet you have measured by 43,560 to obtain the acreage (in decimal form).

Example:

• If you are going to spray 20,000 sq. ft, 20,000 divided by 43,560 = 0.459 acre
• The label states 3 pints of product per acre. Multiply the label rate per acre by the decimal for your area

3 pints multiplied by 0.459 = 1.38 pints

• Remember there are 16 fl oz in 1 pint.

7.12.4 Measuring Small Amounts of Pesticide

Measuring equipment. Always use measuring equipment that is dedicated only for pesticide use. For very small quantities of liquids, a syringe can be useful. For powder or granular products use weighing scales, do not rely on a measuring cup as the bulk density of products varies.

Safety. Be sure to wear the proper protective clothing and equipment as required on the pesticide label. Always be aware of watercourses, neighboring properties and changes in the weather.

Measuring small amounts. The following tables and examples provide information on converting pesticide rate amounts for smaller areas.

Powders and Granules

Example: The label states 3 lbs of powdered product per 100 gallons but you only wish to use a backpack sprayer with a 5-gallon tank. Table 7.12.1 shows you need to mix in 2-3/8 oz of powder. Use clean weighing scales to provide the correct amount of powder, NEVER use a volumetric measure, e.g. a measuring cup, because the bulk density of different products varies.

Liquids

Example: The label states 4 pts of a liquid product per 100 gallons of spray but you only wish to use a backpack sprayer with a 5-gallon tank. Table 7.12.2 shows you need to mix in 3-1/4 fl oz of liquid product. Use a clean measuring cylinder or vessel to provide the correct amount of liquid.

7.11. Cleaning Sprayers

7.13 Application Equipment Distance Learning