Purple Nutsedge (Cyperus Rotundus L.) and Yellow Nutsedge (Cyperus Esculentus L.) Management with Tillage and the Herbicides Imazapic and Imazethapyr

Purple Nutsedge (Cyperus Rotundus L.) and Yellow Nutsedge (Cyperus Esculentus L.) Management with Tillage and the Herbicides Imazapic and Imazethapyr
Author: Derek Duane Horrall
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Release: 2010
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Alternating tillage operations with glyphosate applications resulted in the greatest reduction in tuber number, weight, and viability at mid- and late-season sampling dates. In an herbicide screening study conducted for both purple and yellow nutsedge in the field, imazapic applied at the rate of 71g ha-1 early postemergence (EPOST) resulted in the greatest reduction of tuber numbers and tuber dry weights by July and September. Greenhouse studies indicated that EPOST applications of imazapic and imazethapyr 2 weeks after emergence (WAE) were more effective than those applied to purple and yellow nutsedge 4 and 6 WAE. Foliar-only treatments of purple and yellow nutsedge 2, 4, and 6 WAE provided better shoot control than soil-applied treatments. The greatest control of nutsedge, however, regardless of plant age, was obtained by treating both the foliage and soil. It was determined at the conclusion of a year-long greenhouse study that soil-applied imazapic provided better residual control of purple nutsedge than imazethapyr.

Evaluation of Preemergence and Postemergence Herbicide Systems and Physiological Behavior of CGA-362622 on Purple and Yellow Nutsedge (Cyperus Rotundus L. and C. Esculentus L.).

Evaluation of Preemergence and Postemergence Herbicide Systems and Physiological Behavior of CGA-362622 on Purple and Yellow Nutsedge (Cyperus Rotundus L. and C. Esculentus L.).
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Release: 2002
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Purple and yellow nutsedge are herbaceous perennial weeds that are among the world's worst pests. Nutsedge species are problematic due to their perennial nature, longevity of tubers, and prolific tuber production. Due to the relatively difficulty in reducing purple and yellow nutsedge populations, herbicide-management programs in cropping systems that target nutsedge species need to be developed. Field studies were conducted to evaluate potential reduction in purple and yellow nutsedge populations using sulfentrazone and glyphosate management programs and site-specific management in a tobacco and soybean rotation, as well as using sulfentrazone, glyphosate, and halosulfuron management programs in a soybean and corn rotation. All weed management systems reduced purple nutsedge densities similarly in the tobacco and soybean rotation. Sulfentrazone plus clomazone preplant incorporated (PPI) in tobacco or preemergence (PRE) in glyphosate-resistant (GR) soybean reduced yellow nutsedge densities 82 and 99%, respectively. Postemergence (POST) treatments of glyphosate in GR soybean did not increase yellow nutsedge reductions when sulfentrazone was applied in tobacco or GR soybean. Glyphosate applied on a site-specific basis POST with a light-activated hooded sprayer (LAS) reduced yellow nutsedge populations as effectively as glyphosate POST broadcast treatments in GR soybean. Weed management systems that included sulfentrazone PRE fb the LAS in GR soybean reduced POST herbicide use by at least 86%, compared to broadcast applications. Sulfentrazone plus clomazone PRE alone in GR soybean followed by (fb) nicosulfuron POST in GR corn reduced purple and yellow nutsedge populations by 48 and 85% relative to the nontreated control, respectively. Clomazone PRE in GR soybean fb sequential treatments of glyphosate POST in GR soybean and in GR corn, reduced purple and yellow nutsedge populations equivalent to soybean PRE herbicide programs and other GR corn POST management programs.