Investigating the efficacy of metazosulfuron herbicide (Ginga, WG 33%) in controlling rice weeds in transplanting system

In order to study the effectiveness of the new herbicide metazosulfuron in controlling weeds and its selective performance on rice, pot and field experiments were carried out at Rice Research Institute of Iran in 2018. In the pot test, the recommended dose of metazosulfuron (83 g ai ha-1) in comparison with the herbicides flucetosulfuron, triafamone + ethoxysulfuron, pyrazosulfuron ethyl+pretilachlor, pretilachlor and thiobencarb in the control of weeds, Bolboschoenusplaniculmis, Paspalum distichum, Monochoria vaginalis, Alisma plantago aquatica, Echinochloa oryzoides and Potamogeton nodosuswere investigated. The results showed that metazosulfuron had ≥98% efficiency in controlling all of the above weeds and provided similar or higher efficiency compared to other registered herbicides. In the field experiment, the efficacy of 0, 41, 83, 124 and 165 (g ai ha-1) metazosulfuron in comparison with pretilachlor+bensulfuron methyl, thiobencarb+bensulfuron methyl, triafamone + ethoxysulfuron, bensulfuron methyl, thiobencarb and hand weeded control was investigated. Different doses of metazosulfuron, except of 41 g ai ha-1, had similar effectiveness in controlling field weeds.Also, the highest paddy yield per hectare (4236 kg) was observed in pertilachlor + benzosulfuron-methyl treatment, which did not show any significant difference with thiobencarb + benzenesulfuron-methyl (4121 kg), the dose of 165 g ai ha-1 metazosulfuron (4103 kg) and manual weeding control (4291 kg). Since no significant difference was observed between the doses of 83, 124 and 165 g ai ha-1 metazosulfuron in terms of paddy yield, the dose of 83 g ai ha-1can be introduced as the best dosage of this herbicide in controlling of weeds.