Reducing Fusarium Hardlock in Cotton with Fungicides. (3639)
Authors:
J.J. Marois* - University of Florida D.L. Wright - University of Florida T.W. Katsvairo - University of Florida P.J. Wiatrak - University of Florida
Abstract:
Harvestable yields of cotton are often reduced by 20 to 60% in the southeastern United States due to hardlock a disease presumably caused by Fusarium
verticillioides. A fungicide X N rate factorial study was initiated in 2001 and 2002 to determine the role of F. verticillioides in disease development. In 2001, the main effects were cultivars (Suregrow 501 BR and DPL 458 B/RR), sub plots were no fungicide and benomyl applications and Sub-sub plots were N rates (0, 67, and 201 kg/ha). In 2002 ‘DPL 555 B/RR’ was treated with thiophanate-methyl either during bloom, at 75% boll opening, during bloom and boll opening (combination) and no fungicide. Natural disease pressure was greater in 2002 than in 2001. In 2001, benomyl increased yield (from 1183 to 1354 kg/ha) for the plots that received 200 kg/ha of N. Thiophanate-methyl also reduced hardlock and increased yield.
Applications made during bloom were the most effective at controlling hardlock, and resulted in 87% yield increase over the unsprayed plots (1345 and 717 kg/ha, respectively). Fungicide applications made at both bloom and boll opening did not increase yield significantly over bloom application (1367 kg/ha) but did further decrease disease.
Speaker Information: Jim Marois, University of Florida, 155 Research Road, Quincy, FL 32351; Phone: 850 875 7155; E-mail: [email protected]
Session Information: Thursday, November 4, 2004, 7:55 AM-10:15 AM Presentation Start: 9:30 AM
Keywords: cotton; fungicides; Fusarium; hardlock
