The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Monday, January 28, 2008 - 3:20 PM
Managing Noxious and Invasive Weeds in Pastures and Rangeland
Byron B. Sleugh, P. Burch, M. Halstvedt, W. Kline, V. Langston, R. Masters, M. Melichar, and V. Peterson. Dow AgroSciences, 6887 Dakota Dr., West Des Moines, IA 50266
With the introduction of the new reduced risk and non-restricted use active ingredient, aminopyralid, from Dow AgroSciences, successful strategies for managing many noxious and invasive species in some of the most ecologically sensitive sites, including pastures and rangeland, can be developed. Aminopyralid is a pyridine carboxylic acid herbicide developed for selective broadleaf weed control in sites such as rangeland, pastures, rights-of-way, non-cropland, and natural areas. Aminopyralid is effective at rates between 53 and 120 g acid equivalent (ae) ha-1 in rangeland and pastures with little to no injury to many cool- and warm-season grasses and is available commercially in the USA and Canada in two products, Milestone® and ForeFront R&P®. Aminopyralid and other Dow AgroSciences active ingredients consistently provide excellent control of invasive and noxious weeds such as Canada thistle (Cirsium arvense), musk thistle (Carduus nutans), spotted knapweed (Centaurea maculosa), tropical soda apple (Solanum viarum), Sericea lespedeza (Lespedeza cuneata), and kudzu (Pueraria lobata) and others in a wide variety of environments. Two years after fall applied aminopyralid treatments to Canada thistle regrowth, 87%, 90%, and 93% control was observed for 90, 105, and 120 g ae ha-1, respectively. Two months after treatment, tropical soda apple was controlled more than 90% with Milestone rates of 105 to 120 g ae ha-1. Spotted knapweed was controlled 100% at 426 days after application of 105 to 120 g ae ha-1 aminopyralid in May, June or September. PastureGard® at 420 + 105 g ae ha-1 (triclopyr + fluroxypyr, respectively) or approximately 2 pints of product acre-1, provided greater than 90% sericea lespedeza control at 428 days after treatment. These results indicate that herbicides are an important part of integrated approaches to managing noxious and invasive weeds in rangeland and pasture systems.
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