What is the main feature of a rotary dust blower?

The main feature of a rotary dust blower is its ability to generate an airflow that is effective for distributing dust formulations of pesticides over large areas. This is typically achieved through a hand-cranked fan mechanism, which allows operators to control the flow of air used to project the dust onto the target area. The design is optimized for the dispersal of granular materials, making it particularly useful in agricultural settings for controlling pests by applying dust-based pesticides.

The other options do not accurately describe the primary function of a rotary dust blower. An automatic pressure regulation system is more characteristic of spray equipment that requires consistent delivery of liquid formulations, rather than dust. The ability to spray both liquid and granular pesticides would generally describe more versatile applicators rather than specialized dust blowers, which focus primarily on dust applications. Lastly, a built-in mixing chamber for liquids pertains to equipment designed for liquid formulations, which is not a function of rotary dust blowers, as they are intended for solid pesticide formulations.