Formulations for Spraying
Part 2, Section 1: Pest Management
Pesticides and Their Application
Formulations for spraying
Emulsifiable concentrates (EC or E) are liquid formulations with an active ingredient that is dissolved in one or more petroleum-based solvents. An emulsifier is added to cause oil to form tiny globules, which disperse in water. The formulation then will mix readily with water for proper application. Emulsifiable concentrates usually contain between 2 and 8 pounds of active ingredient per gallon.
Emulsifiable gels (EG) are herbicides that traditionally are emulsifiable liquids formulated as gels. The gels typically are packaged in water-soluble bags (WSB) and are stable at temperatures ranging from -20° to 50°C. In addition, the gelling process reduces the need for nonaqueous solvents compared to standard nonaqueous EC-type formulation processes.
Wettable powders (WP or W) are finely ground dry particles that may be dispersed and suspended in water. They contain from 25% to 80% active ingredient. Suspensions of wettable powders appear cloudy. Wettable powders are nearly insoluble and require agitation to remain in suspension. Atrazine and linuron are formulated as wettable powders.
Soluble powders (SP dissolve in water to form a true solution. Once the powder is dissolved, the spray mixture requires no additional mixing or agitation. However, few pesticides are available as soluble powders because most pesticide active ingredients are not very soluble in water.
Dry flowables (DF), also called water-dispersible granules (WDG), are wettable powders formed into prills so they pour easily into the sprayer tank without clumping or producing a cloud of dust. Nearly insoluble, they require agitation to remain in suspension. Atrazine and linuron also are formulated as dry flowables.
Flowables (F) or water-dispersible liquids (LF) are finely ground wettable powders already suspended in a liquid carrier so they can be poured or pumped from one tank to another. They usually contain at least 4 pounds of active ingredient per gallon of formulation. Flowables are nearly insoluble in water and require agitation to remain in suspension. Atrazine and linuron also are formulated as flowables.
Microencapsulated (ME or MT) pesticides are encased in extremely small capsules that can be suspended in a liquid carrier and pumped and applied with normal equipment. Microencapsulated formulations are nearly insoluble in water and require agitation to remain in suspension. The active ingredient is slowly released over a period of time, often resulting in better pest control. Lasso is formulated in microcapsules, which extend the soil activity and improve weed control.