The Southern San Joaquin Valley is known as a diverse agricultural region, not only for crops but also dairy production. Seed corn grows very well within the region with harvest occurring early in the late summer and early fall. For the Delta Mosquito and Vector Control district, harvest season coincides with the height of the West Nile virus (WNv) transmission cases found in birds, mosquitoes and potentially humans. The corn fields contribute greatly to the WNv issue since they provide a dense canopy and attractive food source for many birds, particular corvids and songbirds. To complicate matters, corn requires standing irrigation until harvest, and often the irrigated water is supplied from local dairy farm operations. This contributes to highly organic standing water from which the main mosquito disease vectors, Culex quinquefasciatus, Culex tarsalis and Culex stigmatosoma are attracted to as breeding habitat, with the birds serving as a convenient blood meal for the adult mosquitoes. The tall, dense corn vegetation further complicates vector control efforts as larval surveillance is hindered and conventional ground based applications of larvicides and adulticides are often ineffective in reducing the mosquito populations to acceptable levels. With all these factors considered, the use of unmanned aerial systems (UAS aka "drones") were implemented to assist in controlling the vector populations within the corn fields.
