Pesticide Handling, Mixing, and Loading
Mixing and loading are among the highest-exposure activities because concentrated product is handled. Candidates must understand closed systems, measuring and pouring technique, triple rinsing, compatibility, and spill readiness. Always read the label for mixing order and compatibility, and never mix concentrates together before confirming compatibility. Use a closed transfer system where required by the label.
Key concepts: rate calculation (amount of product per acre or per 100 gallons), carrier volume, surfactants and adjuvants, and water quality (pH, hardness) effects on product performance. Understand tank mixing order: generally, fill the tank partway with water, add products in the label-recommended order (often wettable powders and dry formulations before liquids, and adjuvants last), and maintain agitation. Triple rinsing empties, rinses, and drains containers three times, adding rinse water to the spray tank where allowed.
Traps: Adding concentrate to an empty tank; mixing incompatible products and causing a tank sludge; assuming "more is better" (overdosing violates the label and increases risk); forgetting that rinse water must be disposed of according to the label and state rules. Also watch for questions about back-siphoning prevention and anti-siphon devices.
Rule of thumb: Water first, then products in label order, adjuvants last; rinse containers three times and put rinsate in the tank if the label allows.
Worked example: A label calls for 2 pints per acre in 20 gallons of carrier per acre. For a 15-acre field, you need 30 pints of product and 300 gallons of spray mix. Confirm compatibility and mixing order before adding anything to the tank.