Efficacy of new herbicides triafamone + ethoxysulfuron, flucetosulfuron and pyrazosulfuron-ethyl on paddy fields weed control

Field experiment was conducted at Rice Research Institute of Iran, Rasht in 2017 to study the efficacy of some new herbicides in controlling the weeds of rice fields in comparison to current herbicides. Treatments were included: triafamone+ethoxysulfuron (Council), flucetosulfuron (Zechor), pyrazosulfuron-ethyl 10% WG (Saathi), Pyrazosulfuron-ethyl 75% WG (Piroz) (all in recommended and two times the recommended dosage) and recommended dose of current herbicides, butachlor (Machete)+bensulfuron-methyl (Londax) and pretilachlor (Rifit)+bensulfuron) plus weedy and hand-weeded control. Results showed that new herbicides, up to two times the recommended dosage, did not have any phytotoxicity symptoms on rice while recommended dosages of common herbicides led to 5-15% phytotoxicity. The efficacy of new herbicides (flucetosulfuron and triafamone+ethoxysulfuron) in weed controlling was similar to common herbicides, while the efficacy of both pyrazosulfuron formulations was not acceptable. Overall, the results of this study showed that two new herbicides (flucetosulfuron and triafamone+ethoxysulfuron), due to high efficiency in controlling a wide range of weeds has the capacity to be replaced the current herbicides (butachlor and pretilachlor) that are going to be eliminated due to environmental concerns in future.