Glyphosate application using a RPA with different spray nozzles and flight heights

Conventional herbicide application methods can be inefficient, and remotely piloted aircraft (RPA) provide a viable alternative. This study evaluated application quality and weed control efficacy using an RPA and an electric backpack sprayer. A randomized block design with eight replications was used. Treatments consisted of two spray nozzle types (standard flat fan and air-induction flat fan) and two RPA flight heights (3.0 and 4.0 m), plus an untreated control and a standard treatment with a backpack sprayer. The spray mixture contained water, brilliant blue dye, glyphosate, and an adjuvant. RPA treatments achieved higher spray quality on the weed canopy and reduced soil losses compared with the backpack sprayer. Both methods resulted in effective weed control at 21 days after application, particularly the RPA treatments with flat fan nozzles at 3.0 and 4.0 m flight heights. RPA equipped with flat fan nozzles at a 3.0 m flight height achieved weed control efficacy equivalent to that of the electric backpack sprayer (98.5%), demonstrating that RPA technology represents a viable alternative for total-area weed management.