Dusting equipment is available in all practical sizes ranging from one-half to 25 pounds or more in dust capacity. Small piston or plunger-type dusters are convenient when only a few plants are involved, but for the most efficient application on a large area, continuous flow models of the bellows-operated or hand-cranked, rotary type are preferred. Regardless of type, extension tubes or dust-deflecting accessories are essential for coverage of hard to reach places and undersurfaces of low growing plants.
For best results and maximum personal safety, dust when air is calm and plant surfaces are damp, but not wet. Dusting wet surfaces causes unsightly deposits on leaves. After dusting, remove excess dust from the hopper to prevent caking in storage and possible corrosion of metal parts.
Of the many different types of spray equipment on the market, the hose proportioner or hose-on sprayer probably is the most widely used around the home. Its popularity is due mostly to low costs, simplicity, and versatility in applying all kinds of spray materials. This sprayer attaches to the end of a garden hose and meters the pesticide out through a siphon to mix with water from the hose. The chief difference between models of hose-on sprayers is the metering system used to regulate dosage. The simplest models have a non-adjustable nozzle and siphon system calibrated so that a set volume of water is required to empty the pesticide container. These are available in sizes calibrated to deliver three to 15 gallons of spray for each jar of chemical used. Sprayers with the lower rates are best suited for spraying plant foliage; the 15 gallon size is best for lawns.
More versatile types of hose-on sprayers are equipped with an adjustable nozzle so that spray volume can be regulated. These work better with emulsifiable concentrates than with wettable powders. Dosage is regulated by a dial setting that meters out desired amounts of pesticide concentrate for each gallon of spray applied. Using the proper dial setting, the amount of concentrate placed in the pesticide jar does not affect dosage; therefore, do not dilute materials in the jar with water. Some disadvantages of hose-on sprayers are:
- Their use is limited to the area reached by hose
- Difficulty in obtaining uniform spray coverage in large, dense shrubbery and on undersides of low-growing plants
- Water pressure may not be sufficient to break the spray into the fine mist needed for good plant coverage
Compressed Air Sprayers:
These sprayers operate on air pressure (20-80 psi) developed by a hand-operated air pump. They will handle wettable powders as well as liquids, provided the spray tank is agitated frequently to keep material in suspension. Tank sizes range from two quarts to five gallons or more with the largest sizes normally mounted on wheels for handling ease. Quality features for this type of sprayer include a corrosion-resistant tank fitted with a large filler opening for cleaning ease, a pump equipped with replaceable parts and a reasonably long extension tube fitted with a rotating, adjustable nozzle.
These also are hand operated, but operating pressure is developed by the action of a sliding rod or piston to force liquid through the spray nozzle. Pressures up to 180 psi are possible, and liquids can be sprayed up to 30 feet depending on nozzle adjustment. This sprayer most commonly is fitted with a suction hose that can be dropped into any size container of spray mix. The larger models are the best choice of all hand-operated equipment for spraying large shrubs and fruit trees.
Large areas require equipment operated by an engine or tractor power takeoff. Boom-type or single nozzle tree sprayers used for application of fungicides should be equipped with piston-type pumps for handling wettable powder formulations with minimum wear and capable of developing spray pressures in excess of 100 pounds per square inch (psi). Pumps developing 300 psi or greater are needed for certain orchard spraying. Turbine or air-blast sprayers designed to deliver spray materials by wind rather than liquid pressure and gravity are versatile and provide excellent coverage of orchard trees up to 30 feet in height. Smaller editions of the air blast sprayer are the back pack type models commonly called mist blowers. These are useful for estate work, small orchards and commercial greenhouses. Airplane services are available in most localities and often are needed when crops cannot otherwise be sprayed conveniently. Effectiveness of air application depends in large part on environmental conditions. Fungicidal sprays should be applied by air under the combined conditions of low air humidity, temperatures below 85oF and winds not exceeding 15 miles per hour.