Herbicides for control of metsulfuron resistant toothed dock (Rumex dentatus)

Rumex dentatus L. (toothed dock), a major broadleaf weed, is a severe problem of irrigated wheat in particularly no-till conditions of the rice-wheat system in India. Metsulfuron is being used for its control. However, the sole reliance on metsulfuron has led to its resistance evolution in R. dentatus. Pot bioassay studies confirmed high level of metsulfuron resistance with GR۵۰ values ranging ۷۴ to ۹۸ times to that of the most susceptible population. Metsulfuron resistant (MR) populations had indicated cross-resistance to other ALS inhibitor herbicides, triasulfuron, pyroxsulam, and florasulam. The ready-mix combination of halauxifen methyl + florasulam was also poor against MR populations. The most sensitive and resistant populations had GR۵۰ values of ۰.۱۱ and ۱۰.۳۱, ۱.۰ and ۲۶۹.۵, <۰.۹۴ and >۳۰, <۱.۱۳ and ۳۶۲۲.۵, ۰.۱۶ and ۱۰.۱۴ g/ha for metsulfuron, triasulfuron, florasulam, pyroxsulam, and pre-mix of halauxifen + florasulam, respectively. Results showed a high resistance level in R. dentatus against ALS inhibitor herbicides. In addition, a large number of populations (۱۱۹) were also screened across broad herbicide groups used in wheat and ۶۸.۹ % populations exhibited ≤ ۵۰ % control with a recommended field rate of metsulfuron ۴ g/ha, indicating the widespread resistance. However, MR- populations were sensitive to pendimethalin, isoproturon, ۲,۴-D, fluroxypyr, metribuzin, carfentrazone and flumioxazin. So, these herbicides in rotation and as mixture can be used to manage ALS inhibitor herbicide resistance. However, for long-term sustainable management of herbicide-resistant R. dentatus, alternative herbicides should be integrated with best agronomic practices to restrict its infestation in wheat.

کلیدواژه ها:

۲ ، ۴-D ، ALS inhibitor ، carfentrazone ، cross-resistance ، florasulam ، flumioxazin ، halauxifen ، isoproturon ، metribuzin ، Pendimethalin ، pyroxsulam ، triasulfuron