Plant Disease (2015) 99, 1210-1215

Andrew J. Friskop, Thomas J. Gulya, Scott A. Halley, Blaine G. Schatz, Joel P. Schaefer, James G. Jordahl, Scott M. Meyer, Kevin W. Misek, Paul Hendrickson and Samuel G. Markell (2015)
Effect of fungicide and timing of application on management of sunflower rust
Plant Disease 99 (9), 1210-1215
Abstract: Sunflower rust is an important yield-limiting disease in sunflower production in the Great Plains of the United States. Rust severity and incidence have increased between 2002 and 2011, and genetic resistance is limited in most commercial hybrids, particularly the high-value confectionary market type. Although fungicides are available for rust management in the United States, management recommendations are insufficient. Specifically, efficacy and timing data are very limited for fungicides in FRAC groups 7 and 11. Seventeen fungicide efficacy and timing trials were conducted between 2008 and 2011 in North Dakota. Timings evaluated across the four years included single or multiple applications at growth stages (GS): GS V8-V12 (late vegetative), GS R1 (terminal bud formation), GS R3-4 (elongation of bud), GS R5 (flowering), and GS R6 (completion of flowering). With few exceptions, fungicide applications of DMIs and QoIs controlled disease greater than SDHI fungicides. Fungicide applications made at R5, either singly or in combination, consistently resulted in greater disease control. A negative correlation (r = -0.7756) between disease control and yield was observed, resulting in a yield reduction of 6.6% for every 1% increase in disease severity.
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Link to article at publishers website
Database assignments for author(s): Thomas J. Gulya, Samuel G. Markell

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Puccinia helianthi	Sunflower (Helianthus annuus)