Interaction of Prohexadione Calcium with Agrichemicals Applied to Peanut (Arachis hypogaea L.)

Abstract

Abstract A variety of pesticides and foliar fertilizers are applied to emerged peanut. Defining interactions among these agrichemicals is important when formulating pest management and production strategies. Research was conducted in North Carolina during 1999 and 2000 to evaluate interactions among prohexadione calcium at 140 g ai/ha applied with various commercially available fungicides, insecticides, herbicides, and foliar fertilizers. Agrichemical mixtures were applied when peanut vines reached 50% row closure. Prohexadione calcium alone was applied approximately 2 wk later. Twenty-eight percent urea ammonium nitrate was included with prohexadione calcium. In a second set of experiments, control of pitted morningglory (Ipomoea lacunosa L.) and yellow nutsedge (Cyperus esculentus L.) by imazapic plus 2,4-DB, acifluorfen plus bentazon plus 2, 4-DB, bentazon plus 2, 4-DB, acifluorfen plus 2,4-DB, pyridate plus 2,4-DB, and 2,4-DB applied alone or with prohexadione calcium were evaluated. Large crabgrass [Digitaria sanguinalis (L.) Scop.] control by sethoxydim and clethodim alone or with prohexadione calcium was evaluated also. Fungicides, insecticides, and foliar fertilizers did not affect efficacy of prohexadione calcium with respect to visible injury to peanut, row visibility, or maintenance of short stems. Slightly higher injury was noted when acifluorfen, acifluorfen plus bentazon, bentazon, and pyridate were applied with prohexadione calcium. Minor increases in pitted morningglory control and peanut injury were noted when herbicides were applied with prohexadione calcium, most likely due to presence of urea ammonium nitrate. However, prohexadione calcium did not affect large crabgrass control by sethoxydim or clethodim. Collectively, these data suggest that prohexadione calcium and the majority of agrichemicals applied to peanut are compatible.