ATHENS, Ga. – When this year’s pests invade your yard, keep safety in mind before you start spraying pesticides.
“There are several factors to consider before you set out with your handheld or backpack sprayer,” said Paul Sumner, an engineer with the University of Georgia College of Agricultural and Environmental Sciences.
When it comes to small areas, he said, handheld and backpack sprayers are inexpensive tools for controlling weeds, insects and diseases.
“Effective pest control depends on whether you apply the proper amount of pesticide,” he said. “This can only be done if the spray equipment is calibrated accurately.”
Do this first. Sumner suggests a simple, quick test.
First, fill your sprayer with water. Then spray a paved surface in your normal spraying manner on a warm day. In a few minutes, the drying pattern will show how the spray was distributed.
“Fast-drying areas indicate low application rates, while slow-drying areas reveal high amounts of spray,” he said.
“Uniform drying without streaks indicates a uniform application. Using this test as a guide, practice spraying until the water is distributed uniformly.”
Before you spray, remember the wind.
“You want a buffer area between you and downwind because of the possible chemical drift,” Sumner said.
“You don’t want the wind to blow the pesticide to an adjoining area like your flower bed.”
Federal regulations prohibit spraying pesticides outdoors if the wind speed is 10 miles per hour or higher. Sumner is even tougher.
“If the wind is blowing more than 5 mph, you shouldn’t spray,” he said.
Know the wind direction first.
“Select a spraying time when there is little wind or the wind is blowing gently away from unaffected plants,” he said.
“If the conditions aren’t right, consider another method of control or wait to apply the pesticide.”
Know your sprayer. Handheld and backpack sprayers have three main parts: a tank for the spray mix, a pump to provide pressure and a nozzle-wand to spray the chemical.
Most backpack sprayers have pressure regulators that allow spraying at a constant pressure – few handheld sprayers have them.
But it’s important to keep a constant pressure, and “fairly even pressure can be maintained if the hand pump is operated at a constant number of pumps per minute.”
You must know the volume of your tank to know the area you can spray per tankful, he said. Most backpack sprayers hold 4 gallons to 6 gallons and handheld sprayers 1 gallon to 3 gallons.
After you spray, immediately clean your sprayer to prepare for next time. First, remove any remaining pesticide and triple-rinse the tank, he said. If you’ve sprayed a fungicide or insecticide, clean the sprayer with soap and water.
Allow the solution to circulate through the sprayer for several minutes. Then flush the system three times with clean water before storing your sprayer.
Tougher job. Tanks used for spraying herbicides require more attention. Rinse the tank with kerosene, diesel fuel or a comparable light oil. Spray a small amount through the nozzles, too.
After rinsing, fill the tank one-fourth to one-half full with a solution of 2.5 tablespoons of household ammonia to 1 gallon of water. It’s best, Sumner said, to have two sprayers, one for fungicides and insecticides and another for herbicides.
“Cleaning your sprayer is essential,” he said. “If you don’t, the chemicals can dry inside the container, and the residual that bonds to the tank and pump parts will be released the next time you use your sprayer.”
Follow directions. Finally, always follow the pesticide label recommendations precisely.
“Most chemicals sold for homeowners don’t require you to wear protective gear,” he said. “But it’s never a bad idea to wear long sleeves, long pants and shoes when applying pesticides.”
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