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Title: Responses of high O/L peanut cultivars to fungicide for control of Sclerotinia blight

item DAMICONE, JOHN - Oklahoma State University
item Chamberlin, Kelly
item Bennett, Rebecca

Submitted to: American Peanut Research and Education Society Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/13/2016
Publication Date: 12/1/2016
Citation: Damicone, J.P., Chamberlin, K.D., Bennett, R.S. 2016. Responses of high O/L peanut cultivars to fungicide for control of Sclerotinia blight [abstract]. In: Proceedings of the American Peanut Research and Education Society, July 12-14, 2016, Clearwater, FL.. 48:71.

Interpretive Summary:

Technical Abstract: Sclerotinia blight, caused by Sclerotinia minor, remains an important disease of peanuts in Oklahoma where it causes severe damage when prolonged periods of wet weather occur during mid to late season. Progress has been made in increasing the resistance of peanut cultivars to Sclerotinia blight. Spanish cultivars such as Tamnut OL06 and Olin are resistant and application of the fungicides fluazinam or boscalid rarely results in a yield response. However, fungicide application has generally increased yields of runner cultivars such as Tamrun OL01 and Tamrun OL02 classified as moderately resistant. The objective was to use fungicide application as a tool to measure resistance to Sclerotinia blight in new cultivars and breeding lines. From 2008 to 2012, the response of the susceptible cultivar Flavor Runner 458 to fluazinam at 0.75 lb a.i./A was compared to the cultivars Red River Runner and Tamrun OL07. In untreated plots, Flavor Runner 458 averaged 50% disease incidence and 2781 lb/A yield. Red River Runner averaged 34% disease incidence and 3909 lb/A yield, and Tamrun OL07 averaged 28% disease incidence and 3662 lb/A without fungicide treatment. However, 2 applications of fluazinam increased yields (P=0.05) of all cultivars (986 lb/A for Tamrun OL07, 1032 lb/A for Red River Runner, and 1363 lb/A for Flavor Runner 458) suggesting that Red River Runner and Tamrun OL07 have moderate resistance to Sclerotinia blight with additive yield response to fungicide. In 2012, the responses of the new cultivars Lariat (runner), Venus (virginia), and Olé (spanish) to fluazinam were compared to Flavor Runner 458 (susceptible) and Tamnut OL06. In untreated plots, Flavor Runner 458 had 66% disease and yielded 2359 lb/A while Tamnut OL06 had only 4% disease and yielded 3104 lb/A. Lariat had 1% disease and 5037 lb/A yield, Venus had 4% disease and 3467 lb/A yield, and Olé had 1% disease and 4565 lb/A yield without fungicide treatment. Fluazinam increased (P=0.05) yields of Flavor Runner 458 (1271 lb/A) and Venus (753/A), but not Tamnut OL06 (417 lb/A), Lariat (270 Lb/A), and Olé (-37 lb/A). The resistance in Lariat and Olé appears to be sufficient to offset the need for fungicide treatment to control Sclerotinia blight, but the results need to be verified.