Confirmation of metsulfuron-resistant Rumex dentatus in Punjab and Haryana and its management

Abstract

Evolution of herbicide resistance in weed species is a major challenge for the sustainable food security. Resistance to metsulfuron-methyl in Rumex dentatus was first reported from some regions of Haryana in 2014. But, from last few years, there were reports of poor control of R. dentatus by metsulfuron-methyl from Punjab as well as Haryana. The present study was conducted to confirm and quantify the level of resistance in R. dentatus biotypes to metsulfuron-methyl herbicide. Biotypes of R. dentatus collected from the rice-wheat cropping system of Punjab and Haryana were screened out for metsulfuron-resistance using six graded doses namely 0, 1.25 (1/4X), 2.5 (1/2X), 5 (X), 10 (2X) and 20 (4X) g ha−1 of metsulfuron-methyl. Our results revealed that R. dentatus biotypes from Punjab and Haryana were >150 and >200 times, respectively resistant to metsulfuron-methyl than susceptible biotype. Post-emergence application of metsulfuron- methyl plus carfentrazone-ethyl (5+20 g ha−1) resulted in effective control of metsulfuron-resistant R. dentatus biotypes. This is the first report of resistance evolution in R. dentatus biotypes to metsulfuron-methyl in different regions of Punjab under the rice-wheat cropping system.