Author
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Chen, Xianming |
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Wood, David |
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Submitted to: Plant Disease Management Reports
Publication Type: Research Notes Publication Acceptance Date: 1/22/2008 Publication Date: 4/1/2008 Citation: Chen, X., Wood, D.A. 2008. Control of stripe rust of spring wheat with foliar fungicides, 2007. Plant Disease Management Report 2:CF014. Interpretive Summary: Nine foliar fungicide treatments were tested for efficacy to control stripe rust on spring wheat at Pullman, Washington during the 2007 growth season. Stripe rust severities were recorded during the disease development season. Test weight and yield data were recorded at harvest. All fungicide treatments significantly reduced stripe rust severity at eight days after application. Disease control remained effective throughout the remaining growth season. Stripe rust data of the treatments varied significantly, but all were significantly different from the non-treated control. All treatments did not significantly increased grain test weight due to the relatively short duration of stripe rust infection. All fungicide treatments significantly increased grain yield compared to the non-treated control, except for treatments with quilt and one application of fungicide Topguard, in which the increases were not significantly different from the non-treated control. Fungicide treatments increased yield by 26.3 (7.1 bu/A) to 52.1% (14.1 bu/A), which could be valued at $57 to $113/A depending upon the treatment. Technical Abstract: Nine foliar fungicide treatments were tested for efficacy to control stripe rust on spring wheat at Pullman, Washington during the 2007 growth season using a randomized completed block design experiment with non-treated plots as the experimental control. Susceptible wheat variety ‘Lemhi’ was used in the study. Fungicides were applied in 16 gal water/A on different dates and stages depending upon the treatments. The first applications of Topguard for the two-application treatments were done on 21 Jun at boot stage when plants had no stripe rust. The one-time applications of Headline, Tilt, Quilt, Stratego, Topguard, and Quadris were done on 27 Jun when plants were at early heading stage and had 5-10% stripe rust severity. The second applications of Topguard for the two-application treatment were done on 3 Jul when plants were at late heading stage. Stripe rust severity (percent of diseased foliage) was assessed on 21 Jun (boot) just before the first fungicide application and on 27 Jun (heading), 5 Jul (flowering), 12 Jul (milk), and 19 Jul (soft dough) or 7, 15, 22, and 29 days after the first fungicide application, respectively. Plots were harvested on 22 Aug when kernels were naturally dry, and test weight of kernels was measured for each plot. Area under disease progress curve (AUDPC) was calculated for each plot using the four sets of severity data. Relative AUDPC was calculated as percent of the non-treated control. Rust severity, relative AUDPC, test weight, and yield data were subjected to analysis of variance and means were separated by Fisher’s protected LSD test. Stripe rust severity in non-treated control plots was 0, 6.3, 50.0, 95.0, and 100% on 21 Jun, 27 Jun, 5 Jul, 12 Jul, and 19 Jul, respectively. All treatments significantly reduced stripe rust severity at 8 days after application. Disease control remained effective throughout the remaining growth season. AUDPC values of the treatments varied significantly, but all were significantly different from the non-treated control. All treatments did not significantly increased grain test weight due to the relatively short duration of stripe rust infection. All fungicide treatments significantly increased grain yield compared to the non-treated control, except for treatments with quilt and one application of Topguard, in which the increases were not significantly different from the non-treated control. Fungicide treatments increased yield by 26.3 (7.1 bu/A) to 52.1% (14.1 bu/A), which could be valued at $57 to $113/A depending upon the treatment. |
