DRIFT PRODUCED BY TWO PESTICIDE APPLICATION SYSTEMS IN CITRUS ORCHARDS

Abstract

Drift is the most important factor contributing to environmental pollution during the spraying of pesticides. The objective of this work was to evaluate the drift caused by two pesticide spraying systems in citrus orchards. The experiment was conducted in an orchard of Valencia orange, located at the Sertãozinho farm, Escola Superior de Agricultura Luiz de Queiroz, Piracicaba-SP. An air-assisted sprayer with axial fan was used. One system used a prototype for terrestrial application with a rotary disc atomizer that is widely used in agricultural aviation, and the other system used hollow cone tip hydraulics. For treatment of the trees, the insecticide Metidation was used at the dose of 180 g per hectare. To assess runoff losses, glass slides and water-sensitive papers were placed on the ground below the canopy of the trees, while for the evaluation of drift losses the collection surfaces were placed on wooden towers at different heights above the ground. After spraying, the water-sensitive papers were collected and analyzed using a computerized image analysis system, e-Sprinkle (EMBRAPA, Sao Paulo, Brazil), and the glass slide analyzed by the gas chromatography technique. The application system equipped with rotary disc atomizers resulted in a lower pesticide drift in relation to the system that used hydraulic tips. Factors influencing drift are discussed in the present work.