Improving Efficacy of Metribuzin and Rimsulfuron in Potato Production

Rimsulfuron and metribuzin are postemergence herbicides used to control broadleaf weeds in potato and are applied with adjuvants to improve efficacy. Postemergence weed control often coincides with fungicide treatments. Therefore, studies were conducted to determine the effect of adjuvants or fungicides (chlorothalonil or mancozeb) plus metribuzin and rimsulfuron on weed control, potato safety and yield. Common sunflower and common lambsquarters visual control was ? 91% when metribuzin (420 and 210 g ha-1) plus rimsulfuron (26 and 14 g ha-1) combinations were applied with or without fungicides. Past the four leaf stage, metribuzin (340 g ha-1) and rimsulfuron (21 g ha-1) with adjuvants had no effect on hairy nightshade dry weight. Adjuvants and fungicides did not change yield. These studies indicate that including fungicides with metribuzin and rimsulfuron reduce weed populations without negatively impacting yield. Additional research is needed to determine the effect of adjuvants with these herbicides on other weeds