Crop spraying is the process of spraying insecticides, pesticides,
fungicides and other preventative treatments onto crops.
Previously known in agricultural services as 'crop dusting,' the
process is used to cover large areas of crops and protect them from local bugs and pests.
When you press down on the sprayer or pump head,
the piston presses down into the chamber. Whatever is in the chamber needs to escape,
and the easiest path is up through the stem and out the nozzle.
As soon as you release the sprayer head, the chamber fills up with liquid.
The pump draws liquid up a siphon tube from the bottom of the bottle
and forces it through a nozzle. Depending on the sprayer,
the nozzle may or may not be adjustable, so as to select between
squirting a stream, aerosolizing a mist, or dispensing a spray.