Herbicide Efficacy Evaluation

Abstract

The objective of this series of trials was to determine if recently introduced herbicide formulations give better weed control in cereals and grassland than those presently in use. Effect on crop yield and quality was also examined where appropriate. In 1995, field trials were carried out with a new diflufenican/flurtamone formulation, Bacara, in winter wheat and barley. In both cases, the results showed that this new formulation gave commercially acceptable weed control of a wide range of annual weeds and grasses, when applied at doses between 260 and 350 g a.i. per hectare. None of the products tested had any adverse effects on crop yield or quality. Between 1996 and 1998 a number of new sulfonylurea herbicides, based on carfentrazone and flupyrsulfuron methyl (Lexus series), were tested at trial sites in Carlow and Clonmel. Most of the formulations gave weed control similar to Cougar, which was included in all these trials as standard comparison treatment, without affecting crop yield or quality. New herbicide trials for the control of broad and curled leaf dock (Rumex spp.) in pasture were carried out. Most of the herbicides investigated gave better overall control of both species than the standard dicamba/mecoprop based products. One of the sulfonylyurea-based herbicides controlled broad leaf dock only, and occasionally retarded grass development, but had no effect on clover. Fluroxypyr-based products gave long term control of both dock species without any effect on the grass, but eliminated clover present in the sward. In all trials some dock regrowth was evident one year after treatment.