Screening Preemergence and Postemergence Herbicides for Safety in Bioenergy Crops

Interest in the cultivation of bioenergy feedstocks has increased the need for information in this rapidly developing sector of agriculture. Many fast-growing, large-statured perennial grasses have been selected because of their high biomass production potential, competitive nature, and ability to tolerate marginal growing conditions. However, weed pressure in the establishment phase can be detrimental to crop yield. Weed control is one of the most costly and resource-intensive aspects of bioenergy crop establishment. Unfortunately, little information exists on practical weed management techniques for the majority of these new crops. The tolerance of switchgrass, big bluestem, reed canarygrass, sorghum, giant reed, eulaliagrass, and giant miscanthus (sterile and seeded) to 22 PRE and 22 POST herbicides were evaluated. Plants were grown in the greenhouse and evaluated for injury, height, and aboveground biomass after 5 or 7 wk for PRE and POST applications, respectively. PRE and POST application of 2,4-D, bentazon, bromoxynil, carfentrazone, dicamba, halosulfuron, and topramezone did not significantly injure any species. Giant miscanthus was more tolerant to PRE herbicides when established from rhizomes compared with seed establishment. Supporting previous research, all eulaliagrass and switchgrass cultivars demonstrated comparable tolerance to PRE application of all 22 herbicides. With the information gained in this study a suite of herbicides may have potential for use in bioenergy crops; however, they should be tested on larger-scale field trials over multiple growing seasons to validate initial findings. Nomenclature: 2,4-D amine; acetochlor; aminopyralid; atrazine; bentazon; bromoxynil; carfentrazone; dicamba; flumioxazin; halosulfuron; isoxaben; isoxaflutole; mesotrione; nicosulfuron; pendimethalin; pyroxasulfone; sethoxydim; simazine; sulfentrazone; tembotrione; topramezone; big bluestem, Andropogon gerardii Vitman; eulaliagrass, Miscanthus sinensis Andersson; giant miscanthus, Miscanthus × giganteus Greef and Deuter ex Hodkinson and Renvoize; giant reed, Arundo donax L.; reed canarygrass, Phalaris arundinacea L.; switchgrass, Panicum virgatum L. El interés en la producción de cultivos para bioenergía ha incrementado la necesidad de información en este sector de la agricultura de rápido desarrollo. Muchas gramíneas perennes de rápido crecimiento y alta estatura han sido seleccionadas debido a su alto potencial de producción de biomasa, naturaleza com