Author
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Richard Jr, Edward |
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Submitted to: Weed Technology Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/13/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Bermudagrass is a major weed of sugarcane worldwide. In Louisiana, the economic impact of the weed on the sugarcane crop is dependent upon the effectiveness of control measures taken during the 6 to 9 month fallow period between 3-yr crop cycles. In studies to compare the effectiveness of tillage, tillage plus herbicide, and herbicide-only fallow programs to control bermudagrass, it was found that sugar yields in the plant-cane cro were increased between 33 and 71% where bermudagrass was controlled by herbicide-only fallow programs that included a sequential application of glyphosate at 3.36 kg ai/ha each time and only by 11 to 20% by a fallow program consisting of tillage only. When early tillage was followed by a postemergence application of glyphosate 3 to 6 weeks prior to planting, sugar yields approached those obtained where bermudagrass was controlled with sequential applications of glyphosate. Adaption of strategies for the econtrol of bermudagrass in fallow fields that are less dependent on tillag should result in increased plant-cane and ratoon yields and reduced soil erosion. Technical Abstract: Studies were conducted in Louisiana to evaluate the effectiveness of tillage, tillage plus herbicide, and herbicide-only fallow programs in controlling bermudagrass. Sulfometuron applied in the fallow failed to prevent bermudagrass from infesting at least 81% of the newly planted row's surface in December. Tillage three times during the same period reduced bermudagrass infestations in the newly planted crop to 45 to 51%. When th final tillage operation was replaced by glyphosate POST, bermudagrass infestation levels in December were reduced to below 20%. A sequential application of glyphosate was more effective than tillage-only and as effective as tillage followed by glyphosate in reducing bermudagrass infestation levels in the newly planted crop. Application of atrazine or metribuzin in the fallow did not reduce the need for tillage or glyphosate during the fallow period to control bermudagrass, but imazapyr did. Sugarcane shoot populations in December of the fallow year were similar fo the fallow programs despite differences in bermudagrass infestation levels which ranged from 11 to 94%. However, sugarcane stalk numbers and heights and cane and sugar yields in the plant-cane crop the following year were highest where bermudagrass was controlled. Yields were not increased when dalapon was applied to bermudagrass developing in the plant-cane crop. |
