How pesticides are applied does make a difference in effective results, for greatest safety and economy.
Pesticides must be used as directed. Chemicals should always be measured carefully and never used on a windy day when wind “drift” could carry the chemical into areas where it may cause damage.
The proper applicator permits the user to:
Premix the pesticide exactly as recommended and spray or dust it in the right concentration at the right pressure.
Place pesticides where needed. With a long wand and an adjustable nozzle, he can (1) reach into the heart of a plant, covering the stem area and inner growth; (2) spray down to cover tops of leaves; (3) spray up through the plant, placing pesticide on the under sides of leaves where insects hide and fungus diseases often start.
Apply pesticides with the correct spray pattern. He can adjust a cone nozzle to a fine mist that envelopes and penetrates plants to cover all surfaces. He can adjust it to long-range solid stream spray to reach into a tall shrub, tree or vine. Or he can use a fan nozzle cap for a broom-type spray on lawn weeds.
Cut off the spray instantly, just before it begins to run off, preventing over-coverage, waste and harm to the plant and surrounding area.
Problems concerning nonfunctioning sprayers frequently can be traced to corroded metal parts, clogged nozzles or damaged seals.
Corrosion results when chemical solutions are left in sprayers. Clogging happens when dust, sand, soil or undissolved particles of powdered chemicals get into lines and nozzles. These same particles damage seals.
To avoid clogging, dissolve dry powder in a small amount of water before putting it into the sprayer and adding the recommended amount of water.
If you are using wettable powders, shake the sprayer tank occasionally to keep the solution well mixed.
Once the nozzle is clogged, however, remove it from the sprayer and ream it with a toothpick or broom straw-wire could damage the nozzle opening. If this fails, flush and reverse flush with clear water until obstacle is dislodged.
As prevention against cross contamination between chemicals, corrosion or clogging, clean the equipment with a small amount of detergent dissolved in water after each use. Then flush with clean water until sprayer is completely empty. Dry the sprayer and store in a dry place. Cleaning is very important if a herbicide is used in the sprayer because any residue could damage plants sprayed at a later time. It is recommended that a separate sprayer be purchased and used for weed killers only.
Maintenance kits are available so that homeowners can make minor repairs, such as replacing the hose, discharge valve, nozzle, pump cup or an O-ring.
INTERMITTENT HAND SPRAYERS
Forward motion of a hand-operated pump creates a jet of air which syphons liquid from the tank (5-oz. to one quart capacity) and atomizes it at the nozzle. Some hand sprayers produce a fine, floating spray suited for controlling flying insects. Others produce a wetter, heavier spray for treating exposed surfaces where insects feed, lodge or crawl.
Use only oil-based sprays for intermittent sprayers.
CONTINUOUS HAND SPRAYERS
Continuous pumping action creates pressure in tank which forces liquid through nozzle in steady spray permitting rapid and uniform treatment.
Tank capacities range from 20 oz. to 3 qts. Most nozzles are adjustable from fine spray for flying insects and freshening air to heavier residual spray for treating surfaces where insects feed, crawl or rest, for mothproofing, etc.
HYDRAULIC HAND SPRAYERS
Using hydraulic pressure, these one- or two-quart sprayers develop pressure up to 150 lbs. The high pressure breaks spray into extra-fine particles which envelope plants for greatest protection; it also fires a spray up to 15′ (or higher with an extension), reaching tops of small trees or vines. Made of rustless brass with plastic or glass containers, they can last for years.
Hose-end sprayers are best adapted for jobs such as foliar feeding or applying fertilizers, insecticides, fungicides to lawns or gardens where large volumes of water are needed.
Containers are glass or plastic, with 2 to 20 gal. capacity of mixed spray. There are also models that directly mix liquid chemicals with the waterflow without premixing. Some of these have dials for selecting the proportion of chemical to be water sprayed.
Spray pattern is normally a wide fan for lawns, gardens and flowers. A solid stream that carries a distance is possible for spraying trees. Attachments are available to prevent drift when spraying herbicides. The attachments create a gentle, coarse spray.
Use these sprayers with extreme care because overspray and unwanted drift are possible.
SLIDE PUMP SPRAYERS
Slide pump sprayers perform higher pressure and longer reach jobs. They operate on a two-handed, telescopic plunger action which draws the spray material from an open container and discharges it through adjustable nozzle.
They develop pressures up to 150 lbs. and nozzles adjust for spray patterns up to 25′ or 30′. Pumps are corrosion-resistant brass with either continuous or intermittent action.
As their name indicates, knapsack sprayers are carried on the user’s back. Polyethylene models are lightweight and comfortable to use.
Steady pumping maintains a constant pressure which produces uniform discharge rate and spray pattern. Some models require only intermittent pumping. Capacities range from 3 1/2 to 5 gal.
Some sprayers have mechanical agitators to handle wettable powders. Pumping speed determines operating pressure which can reach 150 lbs.
COMPRESSED AIR SPRAYERS
The type of sprayer that has become the most popular is the compressed air (“tank-type”) sprayer. When the sprayer is pumped, air pressure builds in the tank and forces the spray material through the hose, valve, wand and nozzle. Nozzle adjusts spray pattern and the wand facilitates spraying under leaves and other hard-to-reach places.
User has (1) a controlled, premixed and uniform concentration of pesticide; (2) choice of pressure for the job-high pressure for fine, turbulent spray for thorough penetration and coverage; low pressure for a heavier spray with no drift for lawns; (3) control of volume-no over-spray with waste and possible damage.
The sprayers may be carried by hand, over the shoulder or mounted on a caddy. Tanks are usually made of galvanized or stainless steel or polyethylene. Plastic pressure sprayers offer corrosion resistance to volatile chemical mixtures and are lightweight and easy to handle.
They are available in 1 to 5 gal. capacities.
Never fill the tank any more than three-fourths full (or to the spot indicated on the tank). This leaves room for air to be compressed on top of the spray material when the hand-operated pump is activated.
Basic design features to look for on any tank include a wide opening to facilitate filling; easy to close, positive sealing, cap/pump assembly; full-size pump for quick pressurizing; a pressure relief valve that indicates when maximum 45 psi working pressure is reached, avoids over-pressurizing and makes releasing pressure when done spraying safe and easy; comfortable carrying handle; a hose that is long enough for the sprayer to be held at the side while spraying; positive action discharge valve that disassembles for cleaning; inline filters to prevent nozzle clogging; extension wands long enough to reach into and under plants; fully adjustable nozzle tip. Not all sprayers have every available feature. However, sprayers with most or all of these features are the safest and easiest to use.
Power sprayers reduce work because energy is supplied by a gasoline engine or electric motor assuring greater application efficiency. Tank capacities are large enough-10 to 60 gal.-to cover large areas with one filling. For extremely large applications, power sprayers can be towed by garden tractors.
Spray pressure can be adjusted to a constant 250 lbs. An agitator keeps solution mixed so spray pattern and coverage are uniform.
Normally, a power sprayer is used on shrubs, flowers, vegetables and trees, but with the addition of accessories such as lawn booms, hand booms and root feeders they become even more versatile.
Cordless electric models with 1-5 gal. tanks eliminate the work of pumping while doing the spraying, unlike standard compression air sprayers. Rechargeable nickel-cadmium batteries make these models powerful and practical, for those who are unable, or do not want to, pump a conventional sprayer.
Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.