Selectivity and efficacy of herbicide GF-3488, containing synthetic auxins halauxifen-methyl and clopyralid, in winter oilseed rape crops in Ukraine

Halauxifen-methyl is a new synthetic auxin, which in combination with another auxin-like herbicide clopyralid is the active ingredient of complex herbicide GF-3488, that is used for dicotyledonous weeds control in winter oilseed rape crops. The reason of this study was a necessity to test crop selectivity and efficacy of GF-3488 to control dicotyledonous weeds in winter oilseed rape crops in Ukraine and also the possibility of GF-3488 application in the tank mixture with graminicide or/and insecticide to control monocotyledonous weeds and insects. A randomized block experiment was conducted in 2015—2017 in 4 locations. It was found that under spring applying, the GF-3488 is not inferior to another widely used herbicide Galera Super on selectivity to the crop. Herbicide GF-3488 at the rate 1.0 l/ha was significantly better than Galera Super at the rate 0.3 l/ha in controlling of annual dicotyledonous weeds Papaver rhoeas L., Galium aparine L., Consolida regalis S.F. Gray and was effective to control of certain types of cruciferous weeds, which are resistant to Galera Super. Adding graminicide Fusilade Forte and insecticide Nurelle D did not affect the GF-3488 selectivity to the crop and had no negative impact on dicotyledonous weeds control. Efficacy of monocotyledonous weeds control by graminicide did not change in the mixture with GF-3488. It was concluded that herbicide GF-3488 is effective on winter oilseed rape against dicotyledonous weed species. Therefore for the simultaneous control of dicotyledonous and monocotyledonous weeds in winter oilseed rape in the spring after the renewal of the crop vegetation herbicide GF-3488 is advisable to be used in a tank mixture with graminicides, and for simultaneous protection against weeds and pests it can be mixed with insecticides.