Proper Pesticide Applications: Effective Applications

Lawn care operators should keep themselves safe and free from pesticide exposure at all times. If they eat lunch without washing their hands with clean water and soap, they are at risk. If they wear their work clothes for more than one workday without washing them, they are at risk. If they don’t follow pesticide labels, they are at risk. If they don’t carry well-stocked first aid and spill kits, they are at risk.

One of my old co-workers used to take foolish risks. One morning, he approached me as I was loading up and checking my sprayer’s motor oil level. He told me he didn’t want to spend the money on a new pair of workboots. Instead, he tried to make the ones that he had last as long as possible. "I think it is about time I get new boots, though," he told me. "Whenever I put these on, my feet start to tingle."

This is just one example of a foolish risk. Obviously, lawn care operators should never wait until their feet start to tingle before purchasing new boots. New boots should be replaced at least once a year. The purchase date should be written inside the boot with a permanent marker so lawn care operators know when they were purchased and when they should be replaced.

Taking such a dangerous approach to working with pesticides can result in problems with even more severe implications.

TAKE THE TEST. No, this isn’t another test to add another category to a pesticide applicator’s license. This test requires lawn care operators to accept the assistance of a medical doctor and give some of their blood. Lawn care operators who don’t regularly get a cholinesterase test put themselves at risk.

Cholinesterase is a chemical found in the human body that is necessary for the nervous system to function normally. Pesticides classified as carbamates or organophosphates can inhibit cholinesterase in your body. Ideally, pesticide applicators should determine how much cholinesterase is in their bodies to begin with so they can use that figure as a baseline for future tests. Typically, this test should be administered every year or after any incidents where unhealthy exposure may have occurred. (NOTE: Cholinesterase tests are not useful for n-methyl carbamate. Consult a physician with questions about this.)

WORKING WITH LIQUIDS. Regardless of what type of liquid product a lawn care operator is applying, one of the main benefits of this type of application is its ability to be active upon application. Typically, the product begins to work immediately upon application. This provides an obvious advantage over granular applications, which need to be watered in.

The best lawn spray pattern is one that delivers uniform coverage with little overlap. The spray pattern should be continuous and uninterrupted, although some overlap might be useful at times.

Lawn care operators worried about getting good coverage, especially with new employees, should cut their application rates in half and make two applications. First, apply in east-west swaths, then in north-south swaths. The spray pattern should form an arc no more than 3 to 4 feet on either side of the applicator’s line of travel. This may not always be an ideal approach because the application time will be doubled, but spending more time on an application is better than customer cancellations or callbacks.

However, applicators must be careful when working with liquid products. Lawn care operators are generally exposed to liquid formulas through their skin, where the product can penetrate and enter the blood stream. Lawn care operators should follow pesticide labels, and safeguard themselves with properly stocked first aid kits (see Stock the Kit, page 112).

TANK MIX TROUBLES. Sooner or later, lawn care operators have to perform liquid herbicide applications, if they haven’t already. Some lawn care companies have dedicated equipment for herbicides and insecticides. Pesticide applicators who work for companies that operate this way should consider themselves fortunate because they won’t have to worry about decontaminating the equipment between herbicide and non-herbicide applications.

Technicians who don’t have this luxury need to ensure a clean tank before each application. First, flush the sprayer with water and spray this water on a site that is listed on the label, immediately after the application. Applicators should do this until they are confident the sprayer is free of residual product. Next, rinse the tank at least three times with water. This should be timed so that the final rinse is completed just before the tank is filled with the new non-herbicide product.

Note that not all kinds of herbicides can be totally decontaminated from a sprayer. For example, tanks that contain phenoxy products cannot be decontaminated. Check the label to be sure. The key is to make sure residual herbicides aren’t being sprayed while non-herbicide products are being applied.

Recently, I heard a story where an applicator was performing a fall liquid fertilization. The applicator didn’t know that the tank was previously used to apply a broad-spectrum herbicide. When the lawn started to turn chlorotic a "red flag" immediately went up. If the previous applicator had followed a few simple procedures, this mishap would not have happened.

If you apply herbicides that cannot be totally decontaminated, buy two sprayers - one for herbicides and another for other pesticide applications - and mark them clearly.

SPILL CONTROL. Spills can and do occur. What should be included in a truck’s spill response kit? Remember that one of the most important components of spill management is to prevent yourself from becoming a part of the spill. Wear your personal protective equipment (PPE) according to what the pesticide labels require. PPE should include:

• Chemical splash goggles
• Face shields
• Rubber gloves
• Appropriate body protection, such as protective suits and shoe or foot coverings

Once lawn care operators are protected, they can stop the spill and prevent it from spreading. This might be as simple as turning off the sprayer or standing up a tipped container. Certain supplies should be carried to help confine spills, including:

• Large, absorbent tube socks manufactured specifically for pesticide absorption
• Pillows manufactured specifically for pesticide absorption
• Absorbent sheets and pads

After the spill has been cleaned up, the residues must be managed. Use the following materials to finish the job:

• Absorbent material such as cat litter
• Broom with metal and plastic dust pans
• Large plastic freezer bags
• Five-gallon disposal container with heavy plastic garbage bags

GOING GRANULAR. Granular pesticides are generally easier to clean up than liquid formulas, and many lawn care operators feel they are easier to work with. Environmental pressures and new legislation are also driving the popularity of granular products.

Case in point, new legislation has been passed in some counties in New York through the state Department of Environmental Conservation (NYSDEC) requiring pesticide applicators to give their clients’ neighbors 48 hour pre-notification of pesticide applications. NYSDEC created a list of pesticides exempt from this pre-notification, one of them being granular pesticides. To avoid notifying all neighbors of a client, lawn care companies in these counties will have to switch from liquid applications to granular.

The key to an effective granular application is often the spreader. Drop and rotary spreaders are most commonly used in commercial granular applications. Drop spreaders measure the fertilizer out and drop it directly on the lawn. They are generally more precise and usually deliver a better pattern. Off-target drift is usually kept to a minimum because the product drops straight down. However, because the swath is much narrower than with a rotary spreader, more care is required to align swaths to prevent overlapping or missing areas. A helpful hint to ensure even coverage when using a drop spreader is to make sure the wheels overlap wheel marks in the grass from the previous swath.

Rotary spreaders are more forgiving if the applicator isn’t as accurate. Because the application pattern is feathered to the far left and far right of the swath, some overlap is tolerable and sometimes even desirable. Rotary spreaders utilize centrifugal force which provides wider swaths, thereby reducing the number of swaths required. Because of this, rotary spreaders are more likely to cause drift if they are used on windy days.

Regardless of the type of spreader a lawn care operator uses, over-application at the ends of the lawn should be avoided. Inexperienced applicators either open the spreader too early when they begin the swath or turn it off too late at the end of the swath. Never keep the spreader open when turning around at the end of the swath.

Get the spreader moving at its rated speed (often 3 miles per hour - check the owner’s manual) before opening the spreader. Apply a ring around the lawn (that will act as a header strip) before starting the back and forth swaths. The perimeter of the lawn will then serve as the turn-around area where the spreader should be closed. Closing the spreader minimizes the chance of irregular or over application.

Almost every lawn pesticide applicator has at one time or another striped a lawn. Striping occurs when the swaths are applied unevenly and results in stripes of dark and light green turf. This could have happened if the spreader isn’t calibrated properly for the application or if the spreader isn’t being driven accurately. Some lawn applicators will run their swaths at a right angle to the home so striping is less noticeable when the homeowner looks out the window. This is no substitute for doing the job right.

Also, never operate the spreader backwards. Rotary spreaders will produce an unacceptable pattern when moved in this direction, while drop spreaders will apply granules at a different rate. If you need to operate a drop spreader backwards (such as in soft soil with new seeding where pulling the spreader may be easier than pushing), make sure it is calibrated for pulling rather than pushing.

Finally, spreaders should always be filled on a driveway or walkway instead of a lawn. Granules are much easier to sweep off of a hard surface.