POST herbicide programs utilizing tribenuron for cleavers (Galium aparine L.) control in winter wheat cultivars

Cleavers (Galium aparine L.) causes severe problems in winter wheat (Triticum aestivum). Four field experiments were performed at Kayakenstky and Stalskiy regions, southern Russia over two growing winter seasons 2015 and 2016 to evaluate postemergence (POST) applications of herbicides (Flucarbazone, metsulfuron, 2,4-D, fluroxypyr, tribenuron, pyroxsulam and sulfosulfuron) applied alone or in tank mixtures on winter wheat cultivars. Wheat injury from herbicide application was minor, with the exception of pyroxsulam + sulfosulfuron in 2015, and tribenuron + pyroxsulam in 2016 at Kayakenstky. Best cleavers control was observed in treatments containing tribenuron. Cleavers were controlled least by metsulfuron (study 1) and flucarbazone (study 2), whereas cleavers had intermediate growth inhibitory responses to the other treatments. Tribenuron + fluroxypyr applied in wheat 'Krasnodar 99', and tribenuron + pyroxsulam in wheat 'Gerda' resulted in enhanced grain yield with the value of 60% and 45.7%, respectively. Overall, tribenuron and herbicides containing tribenuron provided the most efficient control compared to the other herbicides and consistently maintained optimal grain yields in all cases. To improve weed control and to prevent a rapid development of herbicide resistance, tribenuron should be applied in combination with either fluroxypyr, pyroxsulam or metsulfuron.