XXII Congreso de la ALAM

I Congreso de la ASACIM

EVALUACIÓN DE HERBICIDAS CON DIFERENTES MECANISMOS DE ACCIÓN PARA EL CONTROL DE Hirchsfeldia incana L. RESISTENTE A metsulfuron –metil

Mario Raúl Vigna   EEA INTA Bordenave, Ruta 76 km 36.5 8187 Bordenave. vigna.mario@inta.gob.ar

SUMMARY During 2013 season different herbicides were evaluated to control an Hirchsfeldia incana metsulfuron-methyl resistant population in a comercial plot located in Coronel Pringles country (Buenos Aires SW).The objective was to evaluate herbicides with different modes of action regardless of the crop to implant. Two trials were performed: fallowing simulating conditions (15.04.13) and preemergence applications (6.6.13). On 15/4 was evaluated 2,4-D ester 388, diflufenican 100, flumetsulam 96, flumioxazim 57.6, flurochloridone 375, foramsulfuron 36 + iodosulfuron 2.4, imazamox 70, linuron 1500, metribuzin 384, metsulfuron 4.8, sulfometuron 2.3 + chlorimuron 7.5 g , Triasulfuron 7.5 gr i.a.ha -¹ and glyphosate (potassium salt) 810 gr ae. ha -¹ alone and mixed with the above. The weeds were in flowering and seedling emergence started. On 6/6/13 chlorsulfuron 9.4 + metsulfuron-methyl 1.8, diflufenican 100, flumioxazim 57.6, flurochloridone 500, imazamox 70, linuron 1500, metribuzin 384 g i.a.ha -¹ were applied on bare soil. At 40 DAA (days after application) on the first test, the differences were not as obvious as four months later when sulfometuron + chlorimuron, imazamox, foramsulfuron + iodosulfuron, triasulfuron, metsulfuron, flumetsulam and 2,4-D showed very low control and flurochloridone, linuron, flumioxazim and diflufenican were the best. Glyphosate controled the weed. In the second trial flumioxazim, linuron, diflufenican and flurochloridone showed control near to 99% 100 DDA, while imazamox and chlorsulfuron + metsulfuron mixture were approximately 30 and 40% . In this experiences under field conditions the herbicides ALS-inhibitors showed a very low control on H.incana population. Control this weed should be planned using herbicides with other action sites, such as this study case.

XXII Congreso de la ALAM I Congreso de la ASACIM

PRESENCIA DE POBLACIONES DE Hirschfeldia incana (L.) RESISTENTES METSULFURON-METIL EN EL SO DE BUENOS AIRES, ARGENTINA

Mario R. Vigna¹ y Jorge Mendoza².   ¹ EEA INTA Bordenave. Ruta 76 km 36.5 .8187. Bordenave . Correo electrónico: vigna.mario@inta,gob.ar   ² Asesor Privado. 8000 Bahia Blanca Correo electrónico: mendozajor@bbconline.com.ar

Summary: The Brassicaceae species have been a traditional component of the weed community in wheat and barley crops in Buenos Aires SW. Recent years the farmers observed failure of control " turnips " or " beads " with once effective methods . In this frame Hirschfeldia incana (L.) was identified as one of the most persistent species in fields with metsulfuron and glyphosate repeated use on direct drill system history. The aim of this study was to determine the possible resistance to these herbicides in a H. incana population (CF) present in a commercial lot. Herbicides were evaluated in three growth stages under controlled conditions on potted plants grown from seed. Both populations, CF and BO (sensitive or “wild”) showed normal sensitivity to glyphosate. However, doses as high as 256 gr i.a. metsulfuron.Ha¹ were not able to significantly reduce the dry weight/plant of CF, while 2 gr i.a. were sufficient to BO. The growth stage had a minor influence on herbicide response. These results confirm for the first time the presence a Hirschfeldia incana population metsulfuron resistant.