Master of Science (MS)
Plant, Enviromental and Soil Sciences
Propanil has long been a staple of weed management in rice production. The introduction of IR rice allowed for the use of imidazolinone herbicides in crop for the control of red rice. Six studies were conducted in 2011 and 2012 to evaluate the weed control interactions, synergistic, antagonistic, or additive, of imazethapyr or imazamox when mixed in a single application with propanil, thiobencarb, or a pre-packaged mixture of propanil plus thiobencarb. Blouin’s modified Colby’s was used to determine if a synergistic, antagonistic, or additive response occurred. Two studies were established to evaluate imazethapyr at 0 and 70 g ha-1, or imazamox at 0 and 44 g ha-1, when mixed with propanil at 1680 or 3360 g ha-1, thiobencarb at 1680 or 3360 g ha-1, a pre-packaged mix of propanil plus thiobencarb at 840 or 1680 g ha-1, and no mixture herbicide. A synergistic response occurred for red rice control at 7, 14, 21, and 49 DAT when imazethapyr was mixed with propanil plus thiobencarb at 840 and 1680 g ha-1; and at 7, 14, 21, and 49 DAT when imazamox was mixed with propanil plus thiobencarb at 1680 g ha-1. Two other studies were established to evaluate imazethapyr at 0 and 70 g ha-1, or imazamox at 0 and 44 g ha-1, was mixed with propanil at 0, 1.12, 2.24, 3.36, or 4.48 kg ha-1.A synergistic response occurred for red rice control at 7 and 14 DAT when imazethapyr was mixed with propanil at 2.24, 3.36, and 4.48 kg ha-1; and at 7, 14, 21, 28, 35, and 49 DAT when imazamox was mixed with propanil at 3.31 and 4.48 kg ha-1. The addition of propanil, thiobencarb, or a pre-packaged mixture of propanil plus thiobencarb in a mixture with imazethapyr or imazamox can increase the overall weed spectrum from the herbicides applied alone. The addition of multiple herbicide modes of action in a single application can help prevent or slow the development of herbicide resistant weeds as well as red rice outcrossing with IR rice.
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Fish, John Caleb, "Interactions of Herbicide Mixtures in Imidazolinone-resistant Rice" (2014). LSU Master's Theses. 2575.
Webster, Eric P.