4. Eliminate Leftover Spray Mixture

Avoid leftover diluted pesticide in your spray tank following a pesticide application. A few simple calculations can be used to determine the amount of spray mixture needed to spray a given size of field (Fig. 2). Follow these steps to determine the amount of water and pesticide concentrate you need to add to the tank:

1. Determine the area to be sprayed (acres, square feet etc.)
2. Multiply this area by the application rate of the sprayer to find the amount of spray mixture needed in gallons.
3. Multiply the area to be treated by the pesticide rate to determine the amount of pesticide you must add to the tank.

Example

A sprayer has been calibrated to apply 15 gallons of spray mixture per acre. The pesticide label recommends 2 pints of commercial product per acre for broadcast application. Determine how much water and pesticide must be added to cover 10 acres.

Spray Mixture Needed = Spray Output (GPA) x Acres to be Sprayed

= 15 gal/acre x 10 acres = 150 gallons of spray mixture

Amount of Pesticide Needed = 10 acres x 2 pints/acre = 20 pints (2.5 gallons)

So, if the total solution should be 150 gallons, the final mixture should contain 147.5 gallons water and 2.5 gallons of pesticide formulation.