Effect of carrier volume and nozzle type on spray deposition within the canopy, disease control and yield in peanut

Effective disease and pest management in peanut (Arachis hypogea L.) requires adequate spray penetration within the canopy during pesticide applications. Field studies were conducted to assess spray deposition within the peanut canopy at three carrier volumes of 10, 15 and 20 gallons per acre (GPA), with each volume applied using three different nozzle types (extended range [XRC], air induction extended range [AIXR], and Turbo TeeJet Induction [TTI]). Spray deposition was assessed using water at various application timings (45, 60, 90, and 120 DAP) by placing water-sensitive paper at upper, middle, and lower positions within the peanut canopy. Fungicide applications using different carrier volume and nozzle treatments were made at regular intervals throughout the season, and disease ratings along with peanut yield were recorded at harvest. The carrier volume of 20 GPA consistently provided the greatest deposition in the upper and middle canopy, followed by 15 and 10 GPA. The XRC nozzle exhibited the greatest deposition in the upper canopy, followed by the AIXR and TTI nozzles. Within the lower canopy, the effect of carrier volume and nozzle type on spray deposition varied among the application timings. For disease control, the lower carrier volume of 10 GPA and XRC nozzle showed an increased incidence of late leaf spot (Nothopassalora personata) and southern stem rot (Sclerotium rolfsii Sacc.) in one of the study years. Carrier volume and nozzle type did not affect peanut yield during both years. Overall, the findings suggest that spray deposition within the peanut canopy is influenced by carrier volume and nozzle type; however, it does not necessarily lead to reduced peanut yield, especially in most fields with low to moderate disease pressure.