By: Clemson University Cooperative Extension
(Columbia) Feb. 9, 2007 - Weeds are abundant in some of our lawns. Some of us will do nothing about them and soon, others will apply a herbicide to control this pest. Controlling a pest with pesticides is not as simple as it sounds. Timing the application as stated on the label is essential for control. Pesticides are not the same by any means. All are toxic in some way to control the specific problem on a specific plant but can be used safely if applied correctly.
Pesticide is a broad term for many types of products; herbicides control weeds, insecticides control insects, fungicides control fungi, etc. It=s disturbing when the caller indicates they have used a herbicide to kill the insects on their favorite shrub. This situation should NEVER happen. Every pesticide has complete directions on the attached label for proper application and safety. Before purchasing a pesticide the applicator should read and understand the information on the label and make sure the product is appropriate for the problem.
The first thing a gardener should do before purchasing or applying a pesticide is to determine what pest is present and the type of plant it is damaging. If the label does not indicate that the pesticide can be used for the pest and plant or area, put it back on the shelf and find another product that will. Ask for help from your local County Extension Office or the personnel at the point of purchase.
Proper application of the pesticide selected is essential for control. It is untrue to think if a little will work, a lot will do better. It=s just not like that! Increased rates can lead to poor plant health, resistance by the pest to pesticides and environmental contamination.
A sprayer calibration is essential to proper application. Calibration is simply knowing how much area is covered by a known amount of pesticide and water mixture. After this is established, the correct amount of pesticide can be mixed to get the right formulation. A sprayer calibration takes some time but is easy.
There are several different ways to calibrate a hand sprayer. Here is one. Put one gallon of water in a clean sprayer. Find an open area in the lawn and mark a starting and an end point. From the starting point begin spraying the water just as you would a pesticide on the lawn until you reach the end. Turn around and go back to the starting point. Continue this until there is no water left in the sprayer. Stop and put the sprayer down at that point. Measure the area sprayed taking in to account the width of your spray and multiply it by the number of passes you made. Repeat this process again and average the two areas. This will give the square feet covered with one gallon of water. Everyone will have a different coverage area so don=t depend on what your neighbor covers in their calibration.
Measure the your lawn or any other application area for application to know how much of a pesticide mixture is needed to cover the area.
Read the label on the pesticide container again to find out how much pesticide is needed per 1,000 sq. ft.
Make the calculations and you are ready to begin. For example, the applicator covered an average of 2,000 sq. ft. with a gallon of water. The area for application is 10,000 sq. ft., and the label rate of the product to apply is 5 oz. per 1,000 sq. ft. To cover the area with the label rate of pesticide, it will take five gallons of water and 50 oz. of pesticide (10 oz. per gallon).
This will take a little time but the benefits outweigh the time involved. Always READ AND FOLLOW THE DIRECTIONS AND INFORMATION ON THE PESTICIDE LABEL BEFORE PURCHASING AND APPLYING A PESTICIDE.