Every year around the start of February, new residents of Davis might think that their being dive bombed. In fact, these planes are crop dusters. Many farmers have their fields sprayed with pesticides, fertilizer and other chemicals and one of the easiest ways to do this is by plane.
The people who fly these planes must be somewhat insane. They fly a few feet off the ground and pull up just in time to avoid telephone wires and cars. It's very beautiful to watch and the chemicals sprayed are harmless to people (?), although fertilizer and some soil treatments can cause eye irritation.
If you're riding your bicycle on the outskirts of Davis, you may be dusted yourself. The crop dusters often cross over the farm roads and don't bother to turn off their spraying nozzles. I've heard this referred to as 'busting' (biking + dusting?). If this happens to you, it might be a good idea to rinse off your bike (or car) to prevent rusting (treat it like you just rode over a salted road).