Wettable powders must be continuously agitated in the spray tank because they are not in solution or emulsion, but rather are held in suspension through agitation. Dsst formulations are similar to wettable powders except they are applied as a dry dust. In Kansas commercial agriculture, dust formulations are rarely used anymore. Aerosols are usually in a pressurized container. By pushing the valve nozzle, a very fine-droplet mist or aerosol is shot into the surrounding air or onto a target surface.
Fumigants are chemicals that are highly volatile.
Some fumigants are kept as liquids under pressure. When released they go directly into the true gaseous state. Other fumigants are formulated as dry tablets or pellets which, upon exposure to moisture in the air, chemically react to produce highly toxic gases. Fumigants are not fine droplets like an aerosol, but are, in fact, true gases. Granular formulations are made by placing the active ingredient on a core material such as clay, sand or ground corncob.