Nozzle and spray volume effects on site-specific herbicide applications in turfgrass using a remotely piloted aerial application system

Authors: COSTA, AUGUSTO - Texas A&M University; Martin, Daniel; TORRES, UBALDO - Texas A&M University; FLOYD, WESTON - Texas A&M University; Fritz, Bradley; STRAW, CHASE - Texas A&M University; BAGAVATHIANNAN, MUTHUKUMAR - Texas A&M University

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2025
Publication Date: 4/10/2025
Citation: Costa, A.G., Martin, D.E., Torres, U., Floyd, W., Fritz, B.K., Straw, C.M., Bagavathiannan, M.V. 2025. Nozzle and spray volume effects on site-specific herbicide applications in turfgrass using a remotely piloted aerial application system. Weed Technology. 39(e43), 1-9.

Interpretive Summary: The use of remotely piloted aerial application systems (RPAASs) has been recognized as a promising method for herbicide applications in turfgrass, enabling the targeting of specific weed-infested areas instead of indiscriminately spraying the entire terrain, thereby improving efficacy, and reducing environmental loading. However, there is a lack of information on the optimal application conditions for these types of targeted applications. A field study was conducted to better understand how different spray nozzles and application volumes influence the efficacy of these targeted herbicide applications, especially with respect to large crabgrass control. The results showed that the backpack sprayer resulted in significantly more herbicide deposits on crabgrass than RPAAS methods, however weed control was comparable for both methods across the application spray volumes tested, including one that applied undiluted herbicide. This work provides guidance on the interactions between nozzle types and application rate for site-specific, target applications allowing applicators to optimize efficacy while reducing herbicide inputs.

Technical Abstract: Site-specific herbicide applications with remotely piloted aerial application systems (RPAASs) offer the potential for reducing herbicide inputs in turfgrass systems, where applications can be targeted specifically to weed-infested areas rather than broadcast across an entire area. However, information on spray nozzle selection and application volume for this approach is lacking. The objective of this study was to evaluate nozzle type and spray volume effects on site-specific herbicide applications using an RPAAS for large crabgrass control in turf. The research was conducted in 2022 at two locations in College Station, TX. The treatments included three nozzle types [XR 80-015 (conventional, extended range), DG 80-015 (drift guard), and AI 80-015 (air induction) flat fan nozzles] and three spray volumes [10 and 15 L ha-1, applied with a single nozzle RPAAS, and 102 L ha-1 applied with a CO2 powered 4-nozzle boom backpack sprayer]. Two additional treatments were included: a pure formulated herbicide application (without dilution in water) using an RPAAS equipped with an XR 80-005 flat fan nozzle at 4.6 L ha-1 and an untreated control. The backpack sprayer application resulted in the highest spray solution deposits on large crabgrass plants (twelve times more, on average), compared to the RPAAS applications. Spray applications with the XR, DG, and AI nozzles using the RPAAS at 10 and 15 L ha-1, or backpack sprayer at 102 L ha-1, provided similar weed control, indicating that RPAAS-based herbicide applications can be effectively made using a range of application parameters. The pure application of quinclorac at 815 a.i. g ha-1 (4.6 L ha-1) using an RPAAS, without herbicide dilution in the sprayer tank, resulted in similar large crabgrass control compared to other treatments with higher spray volumes, using RPAAS (15 and 20 L ha-1) or backpack sprayer (102 L ha-1). This study provides novel information on spray nozzle selection and application volumes for RPAAS use in turfgrass.