Landscape Leaf-waste Pellets as an Herbicide Carrier for Container-grown Landscape Plants

Abstract

Conventional herbicide applications to container-grown landscape plants, often requires multiple spray applications of herbicides in a growing season and presents problems such as non-uniform application, leaching, run-off, environmental pollution, worker exposure and phytotoxicity to the landscape plants. The use of an organic herbicide carrier could help reduce some of the problems associated with spray applications. Landscape-leaf waste pellets were evaluated as a preemergent herbicide carrier for container-grown landscape plants. Isoxaben, prodiamine and pendimethalin were applied to Chrysanthemum × grandiflorum `Lisa', Euonymus fortunei `Coloratus' and Spiraea japonica `Neon Flash', at rates of 1.12, 2.25, and 2.25 kg·ha-1 active ingredient, respectively, with either water or landscape leaf waste pellets as a carrier. Portulaca oleracea, Senecio vulgaris, and Setaria faberi were seeded following treatment application. Visual ratings on efficacy and photoxicity to landscape plants, and shoot fresh and dry biomass were determined for both weeds and crop plants. Landscape leaf pellets served as an effective carrier for application of prodiamine and pendimethalin and combinations of these herbicides with isoxaben in controlling weeds. Leaf waste pellets as a carrier produced equivalent weed control and phytotoxicity ratings to conventional spray application of these herbicides, on both Chrysanthemum and Euonymus. The pellets did not make a consistently effective carrier for the application of isoxaben alone. Application of herbicides on leaf pellets could result in more uniform herbicide applications, minimize loss of herbicides to the environment and reduce the risk of herbicide contact with nursery workers.