Effect of reduced doses of mesosulfuron + iodosulfuron to control weeds in no-till wheat under Mediterranean conditions

Abstract

Field experiments were carried out over three years (2004-05, to 2006-07) to study the efficacy of a post-emergence dual-purpose herbicide (mesosulfuron -methyl (3%) + iodosulfuron -methyl -sodium (0.6%) + mefenpyr -diethyl (9%) to control Lolium rigidum Gaud. and broad-leaved weeds in no-till wheat (Triticum aestivum L.). A ready herbicide mixture was used at three doses (6+1.2, 9+1.8 and 12+2.4 g a.i. ha -1 ) on two dates (beginning of tillering for L. rigidum and 2-3 pair of leaves for broad-leaved weeds, and complete tillering for L. rigidum and 5-6 pair of leaves for broad-leaved weeds) with three different application volumes (100, 200 and 300 L ha -1 ). The results of the present study reveal that using lower than the recommended dose (12+2.4 g ha -1 ), the herbicide mixture controls L. rigidum better than it controls some broad-leaved weeds. Effective weed control, which was achieved mainly through the application at the first weed development stage, provided higher grain yields. The lower control efficacy of more developed L. rigidum and broad-leaved weeds and a longer period of competition between crop and weeds are responsible for the significantly lower crop yields for the delayed application. Within each application timing significant differences were obtained among the dose/volume combinations, with the exception of the first application regarding L. rigidum control, indicating that a reduction in herbicide dose is possible, but only for certain dose/volume combinations. Nonetheless, weed control was maintained across an array of dose/volume combinations, especially with L. rigidum, thus, our results demonstrate that reduced doses can effectively control weeds if applied early.Additional key words: application timing, application volume, broad-leaved weeds, herbicide dose, Lolium rigidum Gaud, weed control. ResumenEfecto de la reducción de dosis y volúmenes de aplicación en un herbicida de post-emergencia para controlar malezas en trigo de siembra directa en condiciones mediterráneas Se llevaron a cabo ensayos de campo durante tres años (2004/2005, 2005/2006 y 2006/2007) en una finca en la región de Évora (Alentejo), en el sur de Portugal, para estudiar la eficacia de un herbicida [mesosulfuron metil (3%)+io-dosulfuron metil sodio (0,6%)+mefenpir dietil (9%)] en aplicaciones de post-emergencia en el control de Lolium rigidum Gaud. (Ballico) y de otras malezas de hoja ancha, en un cultivo de trigo en siembra directa. Se aplicó el herbicida a tres niveles (6+1,2, 9+1,8 y 12+2,4 g a.i. ha -1 ), en dos fechas (comienzo de ahijamiento y ahijamiento completo para L. rigidum y 2-3 pares de hojas frente a 5-6 pares para malas hierbas de hoja ancha), y con tres volúmenes de aplicación (100, 200 y 300 L ha -1 ). Con dosis de herbicida más bajas de lo recomendado (12+2,4 g ha -1 ), se controla con más eficacia L. rigidum que las malezas de hoja ancha. Para todas las combinaciones dosis/volumen, las aplicaciones tempranas en los primeros estadios de desarrollo proporcionaron las más elevadas producci...

Herbicide Doses and Application Times in Weed Suppression on Different Red Bean Varieties

“…Increasing the dose of herbicide application from 1.5 to 3 li/ha increased weed control and 3.5 li/ha controlled weeds by 100% (Figure 3). In another experiment [15], it was concluded that although the full dose was better, reduced doses were also effective and controlled weeds desirably. They suggested that to increase the efficiency of reduced doses, herbicide must be applied at early growth stages of weeds.…”

EVALUATING POSTEMERGENCE HERBICIDES FOR BROADLEAF WEED CONTROL IN IRRIGATED BREAD WHEAT (Triticum aestivum L.)

“…The other 6 treatments, including mesosulfuron-methyl + iodosulfuron-methyl-sodium, were excellent on many annual broadleaf weed species, but less effective against milk thistle (S. marianum), as indicated by higher weed biomass (Table 3). In Portugal, Barros et al (2009) found that premix of mesosulfuronmethyl at 12 g ha -1 + iodosulfuron-methyl-sodium at 2.4 g ha -1…”

Evaluating the bio-efficacy of a novel herbicide (Prosulfocarb) on weed control, with a focus on Phalaris minor, in wheat

“…One such approach is the integrated weed management approach. New herbicide molecules like clodinafop propargyl, fenoxapropp-ethyl, Iodosulfuron-methyl sodium and mesosulfuron-methyl was very effective for weed control (Baghestani et al 2008 andBarros et al, 2009) [7,8] , Kumar et al, (2011) [13] , Singh et al, (2012) [9] and Malik et al (2013) [12] and Chitband et al, (2013) [14] reported the tank mixture of clodinafop + metsulfuron, mesosulfuron-methyl + Iodosulfuron-methyl-sodium and clodinafop + metsulfuron with and without surfactant provided excellent control of Phalaris minor, Avena fatua, Chenopodium album, Melilotus spp., Medicago denticulata, Vicia sativa, Rumex spp., Anagallis arvensis, Coronopus didymus, Lathyrus aphaca, Polygonum plebeium, sedges and many other weeds with higher grain yield of wheat. Avena fatua, Avena leudoviciana, Phalaris minor, Poa annua, and other common broad-leaf weeds are among the many annual grassy weeds that are said to be heavily infested in wheat.…”