Mixing, Loading and Calibrating

Maggie Scarbrough

Other pesticides are ready to use but have to be loaded into the appropriate equipment. Examples of these include pet dips, fumigant applicators and shaker-can dusters.


Some pesticides will require calibration and loading, but not mixing. These include some liquids, granulars, some fumigants, and dust formulations.


Pesticides that do not require calibration but do require mixing and loading include plant and animal dips, crack/crevice treatments, and some tree-canopy sprays.


Pesticides that will need calibrating, mixing and loading are most often what handlers face. In these situations, it is important to properly figure amounts for application and calibrate equipment correctly.


Remember that proper calibration is essential for proper application. Wear and tear, aging and damage can affect the calibration of your equipment, which is why it should be checked often.


To calibrate correctly, you will need to use simple arithmetic and the most effective way is with a calculator.


Before calibration, be sure you are using equipment you are familiar with and is designed for the kind of chemical you are using. It should also be the right size and type for the job.


If any of your equipment is not working as it should it will directly affect the amount being applied. To calibrate accurately, begin by checking the parts to be sure they are in good working order and not too worn. Check nozzles and hoses in particular as they have a direct influence on the amount applied.


Some of the equipment that needs calibration includes granule spreaders, mechanical dusters, most sprayers (including backpack, hand-gun, boom, high-pressure, air blast), and fumigant applicators. Though each piece of equipment is operated a little differently, if you understand the essentials of calibration you can apply that knowledge to each situation as needed. Labels will offer suggestions. Manufacturers’ instructions are also helpful.


Many times the speed at which the equipment travels or is being carried will have a direct effect on the rate of application.


When the equipment uses gravity to keep up the flow of a pesticide, calibration is generally easy. They will usually just need to be adjusted for the rate of flow. Therefore if the speed of the equipment is kept even, the pesticide will be released evenly.


When the equipment uses a pump to spread the pesticide, the speed is a key factor. Whether the equipment is carried or is attached to a vehicle, the speed needs to be as consistent and constant as possible to distribute accurately and uniformly. Manufacturers may offer acceptable ranges of speeds, but you have to consider terrain (as this may slow the progress).


If the equipment has multiple means of dispersal, for example two nozzles, you must be sure they are distributing evenly. You should determine whether the pesticide output is over or under the desired output by five percent. There are two ways to check this. Choose a set amount of time (usually one to five minutes) and operate the equipment while jars are attached over the nozzles, hoppers or nozzle clusters. After the set amount of time, measure the amount of pesticide collected in the jars. If they are uneven, check nozzles, hoses, etc. for wear or leaks. If necessary, replace them.


Regardless of the way you calibrate, you will have to measure how much of a pesticide is being applied. Generally you will establish a distance in which to measure this. The rate of application for testing depends on the formulation used. Sometimes you can just use water for testing purposes while other times a pesticide will be required. Follow equipment manufacturer directions.


You can calibrate your equipment by measuring the amount in the tank, operate the equipment for a set distance and at a set rate, and measure the amount needed to refill the tank.