Evaluation and management of acetyl-CoA carboxylase inhibitor resistant littleseed canarygrass (Phalaris minor) in Pakistan

Abstract

ABSTRACTA field survey was conducted for the sampling of Acetyl-CoA carboxylase (ACCase) inhibitor resistance littleseed canarygrass, a major weed of wheat, from Punjab, Pakistan in 2014 for confirmation of resistance. The surveyed regions encompassed four different cropping systems including rice–wheat, maize–wheat, cotton–wheat and mixed cropping. Dose–response assay was conducted for confirmation of resistance. Efficacy of herbicide mixtures including clodinafop–propargyl, metribuzin, pinoxaden and sulfosulfuron at a range of doses was investigated to manage littleseed canarygrass. Results revealed that all populations were resistant to fenoxaprop except PM-BWL-2. The higher level resistance (6.5) was found in populations collected from rice–wheat cropping system. The tested herbicide mixtures at 75% and 100% of the recommended dose of each mixture component provided the effective control of resistant littleseed canarygrass. Mixtures at 50% provided more than 80% control and reduced growth and seed production potential of surviving plants. The confirmation of ACCase inhibitor resistance as the first case of herbicide resistance in Pakistan, leads us to discourage use of ACCase inhibitor herbicides alone. However, herbicide mixtures at 75% and 100% of the recommended dose are suggested to manage this weed for sustainable wheat production in the surveyed cropping systems.