• Citrus Orchard Floor Management 2001-2003: Comparison of a Disk, “Perfecta” Cultivator, and Weed Sensing Sprayer

      Rector, Ryan J.; McCloskey, William B.; Wright, Glenn C.; Sumner, Chris; Wright, Glenn; Department of Plant Sciences, University of Arizona, Tucson, Arizona; Department of Plant Sciences, Yuma Mesa Agricultural Center, University of Arizona, Yuma, Arizona; Yuma County Pest Abatement District, Yuma, Arizona (College of Agriculture, University of Arizona (Tucson, AZ), 2003)
      An optical weed sensing sprayer (WeedSeeker) was evaluated for making postemergence glyphosate herbicide applications in a Yuma, AZ lemon orchard. In addition, mechanical (disk and Perfecta cultivator) and chemical weed control strategies were compared. Results were fairly similar; however, the use of the WeedSeeker units combined with a preemergence herbicide (H1) increased weed control three fold compared to disking (D) and perfecta (P1). Additionally, when the WeedSeeker units were used in conjunction with preemergence herbicides, spray volume was reduced by 66% compared to a conventional sprayer and by 57% when used for postemergence applications only. There was a relationship between weed ground cover and the area sprayed by the WeedSeeker units indicating that maximum postemergence herbicide savings will occur at low weed densities or less than 10% groundcover. The use of a sprayer with an improved suspension system allowed for faster spraying speeds than were possible with the tractor mounted sprayer. Weed control was similar for the conventional and the WeedSeeker sprayer. However, yields were variable for both years. Future investigations will include efforts to develop crop budgets based on experimental operations
    • Citrus Orchard Floor Management 2001: Comparison of a Disk, "Perfecta" Cultivator, and Weed Sensing Sprayer

      McCloskey, William B.; Wright, Glenn C.; Sumner, Christopher P.; Wright, Glenn; Gibson, Rick; Department of Plant Sciences, University of Arizona, Tucson, Arizona; Department of Plant Sciences, Yuma Mesa Agricultural Center, University of Arizona, Yuma, Arizona; Yuma County Pest Abatement District, Yuma, Arizona (College of Agriculture, University of Arizona (Tucson, AZ), 2002-11)
      Mechanical (disk and Perfecta cultivator) and chemical weed control strategies were compared in a Yuma, AZ lemon orchard. In addition, an optical weed sensing sprayer (WeedSeeker) was evaluated for making post-emergence Roundup Ultramax herbicide applications. The use of pre-emergence herbicides in conjunction with the WeedSeeker spray units has the potential to significantly reduce the amount of post-emergence herbicide and water needed to spray flood irrigated citrus orchards. There was a relationship between weed ground cover and the area sprayed by the WeedSeeker units that indicated the maximum herbicide saving will occur a low weed densities. The use of the Kawasaki Mule with its superior suspension system allowed for faster spraying speeds than were possible with the tractor mounted sprayer and this also reduced spray volume per plot. Weed control was similar for the conventional and the WeedSeeker sprayers. Future investigations will include efforts to improve the estimation of percent weed groundcover, the use of higher rates of pre-emergence herbicides and the development of crop budgets based on experimental operations.