Doveweed is a problematic weed species in many agricultural ecosystems as well as on roadsides and rights-of-way. Effective POST chemical control options for doveweed are limited in many cropping systems. Greenhouse studies were conducted to evaluate the effectiveness of metsulfuron-methyl dose and the impact of mixtures and sequential applications of either trifloxysulfuron-sodium or bentazon with metsulfuron-methyl for doveweed control. By 14 d after the initial treatment, applying 0.04 kg ai ha–1 metsulfuron-methyl, either once or sequentially, provided 100% control of doveweed. Application of trifloxysulfuron-sodium at 0.04 kg ai ha–1 alone or in mixture with metsulfuron-methyl (0.04 kg ha–1) did not provide consistent doveweed control nor did it reduce biomass. Trifloxysulfuron-sodium applied alone at 0.08 kg ha–1 or in a mixture with metsulfuron-methyl (0.04 kg ha–1) provided consistent doveweed control (>80%). A single application of bentazon (0.56 kg ai ha–1) was ineffective at controlling doveweed. A single application of the bentazon and metsulfuron-methyl mixture (0.56 + 0.04 kg ha–1, respectively) or sequential applications of either bentazon alone (0.56 kg ha–1) or in mixture with metsulfuron-methyl (0.04 kg ha–1) provided excellent doveweed control (100%) by 35 d after treatment. Overall, single applications of metsulfuron-methyl (0.02 to 0.17 kg ha–1) or mixtures of metsulfuron-methyl with trifloxysulfuron-sodium (0.04 + 0.08 kg ha–1, respectively) or bentazon (0.04 + 0.56 kg ha–1, respectively) controlled doveweed and may be useful for enhancing the control spectrum for other weeds. Sequential applications of the bentazon and metsulfuron-methyl mixture (0.56 + 0.04 kg ha–1, respectively) provided doveweed control and are a resistance-management strategy for doveweed.
Nomenclature: Metsulfuron-methyl; trifloxysulfuron-sodium; bentazon; doveweed; Murdannia nudiflora (L.) Brenan MUDNU