Queensland State Archives posted a photo:
An agricultural aircraft is an aircraft that has been built or converted for agricultural use – usually aerial application of pesticides or fertiliser, but also for hydroseeding.
Crop dusting with insecticides began in the 1920s in the United States. The first widely used agricultural aircraft were converted war-surplus biplanes, such as the De Havilland Tiger Moth and Stearman.
After more effective insecticides and fungicides were developed in the 1940s, and aerial topdressing was developed by government research in New Zealand, purpose-built agricultural fixed-wing aircraft became common.
In the US and Europe, agricultural aircraft are typically small, simple, and rugged. Most have spraying systems attached to the trailing edges of their wings, and pumps are usually driven by wind turbines.
In places where farms are larger, such as New Zealand, Australia, the former Warsaw pact nations and parts of the developing world, larger and more powerful aircraft have been used.
Aerial