Summer weeds including established bermudagrass and nutsedge are of economic concern to alfalfa growers in western Arizona. Two replicated evaluations of norflurazon herbicide applications for summer weed control were conducted on established alfalfa fields in La Paz County. Zorial Rapid 80 WP and Evital 5G herbicides were tested for their effectiveness of bermudagrass and nutsedge control when applied following hay harvest but prior to irrigation in early spring. Zorial 80 WP was applied at 2.0 lb a. i. /acre. Evital 5G was applied at single application rates of 1.5, 2.0, and 3.0 lb a. i. /acre in spring and two split applications in spring and summer for a total of 2.0, 3.0, and 4.0 lb a. i. /acre. Norflurazon applications resulted in bleaching and shoot tip death of established bermudagrass 49 days after a single application (DAT), however by 78 DAT bermudagrass regrowth reinfested all plots resulting in zero control. Purple nutsedge control resulting from a single application of Evital 5G at 2.0 lb a.i./acre was 41, 82, and 35% at 35, 63, and 99 DAT, respectively. However, Zorial 80 WP applied at 2.0 lb a. i. /acre provided only 5, 23, and 0% purple nutsedge control at 35, 63, and 99 DAT, respectively. The limited effectiveness of the Zorial 80 WP spray solution for nutsedge control resulted from poor soil incorporation since the liquid was unable to penetrate the dense nutsedge foliage. The Evital 5G norflurazon formulation provided promising purple nutsedge control following one application to established alfalfa since the weight of the granules allowed the herbicide to reach the soil surface where irrigation could move the herbicide down through the soil profile to nutsedge roots. At 99 DAT a second split Evital treatment was applied to control nutsedge regrowth, and hopefully provide season long control. Nutsedge control results following this second split application are pending.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/202419 |
| Date | 10 1900 |
| Creators | Knowles, Tim C., McCloskey, Bill, McGuire, Jerry, Keavy, Mike |
| Contributors | Ottman, Michael |
| Publisher | College of Agriculture, University of Arizona (Tucson, AZ) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Article |
| Relation | 370106, Series P-106 |
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