Quanshun An1, Dong Li1, Yangliu Wu1, Canping Pan1. 1. Department of Applied Chemistry, College of Science, China Agricultural University, Beijing, People's Republic of China.
Abstract
BACKGROUND: Sprayers have been shown in numerous reports to influence pesticide deposition and distribution significantly, and public concern for their potential risk has been increasing in recent years. In this study, a hand-held gun sprayer and two air-assisted sprayers (a conventional axial fan air-blast sprayer and a tower sprayer) were used to apply myclobutanil and tebuconazole, and their influence on pesticide distribution and deposition in a semidwarf apple orchard was systematically investigated. RESULTS: The coefficients of variation of different canopy zones associated with the tower sprayers were 38.9-41.9% for leaves and 35.5-36.4% for fruit, generally lower than the coefficients of variation related to the other two sprayers. Tests conducted using the air-assisted sprayers recorded an overall higher drift on the adjacent rows than experiments carried out with the hand-held gun sprayer. The results of drift in soil indicated that pesticide was mainly distributed within 5 m downwind of the treated area, and the distribution pattern was influenced by sprayer design. The total pesticide concentration deposited in soil within 5 m during application by the tower sprayer was 0.28 m mg kg-1 for myclobutanil and 0.90 m mg kg-1 for tebuconazole, much lower than that of the hand-held gun sprayer and the conventional axial fan air-blast sprayer. CONCLUSION: The results indicate that the tower sprayer gives a more uniform distribution and guarantees better effectiveness for the phytosanitary treatment. The tower sprayer also protected the soil better and reduced environmental pollution due to its scientific structural design.
BACKGROUND: Sprayers have been shown in numerous reports to influence pesticide deposition and distribution significantly, and public concern for their potential risk has been increasing in recent years. In this study, a hand-held gun sprayer and two air-assisted sprayers (a conventional axial fan air-blast sprayer and a tower sprayer) were used to apply myclobutanil and tebuconazole, and their influence on pesticide distribution and deposition in a semidwarf apple orchard was systematically investigated. RESULTS: The coefficients of variation of different canopy zones associated with the tower sprayers were 38.9-41.9% for leaves and 35.5-36.4% for fruit, generally lower than the coefficients of variation related to the other two sprayers. Tests conducted using the air-assisted sprayers recorded an overall higher drift on the adjacent rows than experiments carried out with the hand-held gun sprayer. The results of drift in soil indicated that pesticide was mainly distributed within 5 m downwind of the treated area, and the distribution pattern was influenced by sprayer design. The total pesticide concentration deposited in soil within 5 m during application by the tower sprayer was 0.28 m mg kg-1 for myclobutanil and 0.90 m mg kg-1 for tebuconazole, much lower than that of the hand-held gun sprayer and the conventional axial fan air-blast sprayer. CONCLUSION: The results indicate that the tower sprayer gives a more uniform distribution and guarantees better effectiveness for the phytosanitary treatment. The tower sprayer also protected the soil better and reduced environmental pollution due to its scientific structural design.