Effect of row spacing on biological control of sicklepod (Senna obtusifolia) with Colletotrichum gloeosporioides |
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Authors: | C Douglas Boyette Robert E Hoagland Mark A Weaver |
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Institution: | USDA-Agricultural Research Service, Southern Weed Science Research Unit , Stoneville , MS , USA |
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Abstract: | In field experiments conducted over 3 years, the mycoherbicidal fungus Colletotrichum gloeosporioides, formulated either in 20% (v/v) unrefined corn oil and 0.2% Silwet L-77 surfactant or with an invert emulsion, provided season-long control of Senna obtusifolia in narrow (51 cm) rows of soybean. However, in wide (102 cm) rows, one application of either formulation failed to provide season-long control of S. obtusifolia, and two applications were required to achieve season-long weed control. In narrow (51 cm) rows, one application of the fungus either in unrefined corn oil or an invert emulsion controlled S. obtusifolia an average of >90%, and a second application was not required for season long weed control. Soybean yields in wide-row plots treated with two applications of either the fungus/corn oil or fungus/invert emulsion, or with a single application of the fungal treatments in narrow-row soybean plots, were not significantly different from weed-free control plots, or from plots treated with the herbicide chlorimuron. These results suggest that row spacing can affect mycoherbicidal efficacy of this fungus for controlling S. obtusifolia. |
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Keywords: | Colletotrichum gloeosporioides Senna obtusifolia Senna occidentalis bioherbicide microbial herbicide mycoherbicide |
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