Author
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Richard Jr, Edward |
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Submitted to: American Society of Sugar Cane Technologists
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/18/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Bermudagrass is a major grass weed of sugarcane throughout the world. Louisiana has seen an increase in the number of sugarcane fields infested with bermudagrass in recent years because labeled herbicides provide relatively little control. When not controlled, bermudagrass can reduce sugar yields by 10 to 15% during each production year. The objective of this study was to evaluate the effectiveness of a bermudagrass control program for sugarcane that involves the application of mixtures containing non-labeled herbicides in late summer at the time of planting followed by a second application of the labeled herbicide, metribuzin, in early spring at the start of the initial (plant-cane) growing season. Herbicide programs containing an at-planting application of the non-labeled herbicides clomazone or imazapyr controlled bermudagrass better than programs where the labeled herbicides metribuzin or terbacil were applied at the time of planting. As a result of the increased bermudagrass control provided by clomazone and imazapyr, gross cane and sugar yields were increased by 11% when compared to the standard programs. The results of this study are important to the sugar industry of Louisiana and industries throughout the world because currently labeled herbicides are ineffective in controlling bermudagrass within the crop and hand removal is cost prohibitive. Technical Abstract: Experiments were conducted in Louisiana to evaluate the use of systems where at-planting preemergence applications of clomazone or imazapyr in mixture with atrazine and clomazone with sulfentrazone were followed by metribuzin in the spring at the start of the sugarcane crop's initial (plant-cane) growing season. Bermudagrass covered 82% of the plant-cane crop's row top in late May each year in the control. Standard at-planting applications of metribuzin at 2.6 kg ai/ha, terbacil at 1.6 kg ai/ha, or sulfentrazone at 0.6 kg ai/ha applied alone had little impact on bermudagrass cover when followed by metribuzin in the spring. Bermudagrass cover following at-planting applications of mixtures containing clomazone at 2.2 kg/ha with atrazine or sulfentrazone or imazapyr at 0.6 kg ai/ha with atrazine was reduced in May to at least 18% (1992/1993) and 56% (1993/1994). At-planting applications of imazapyr at 0.3 kg/ha controlled bermudagrass at levels equivalent to clomazone at 1.1 kg/ha, while imazapy at 0.6 kg/ha controlled bermudagrass at levels equivalent to the 2.2 kg/ha rate of clomazone each year. Crop injury from the various systems was minimal (<5%) both years. Gross cane and sugar yields were similar to the control where metribuzin, terbacil, and sulfentrazone were applied alone at planting. At-planting applications of clomazone at 2.2 kg/ha in mixture with either atrazine or sulfentrazone or imazapyr at 0.6 kg/ha with atrazine increased cane and sugar yields on average by 11% when followed by metribuzin in the spring. |
