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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #232935
Title: The Effect of Fungicide Applications on Seed Yield in Perennial Ryegrass, and Evaluation of the Rust Model Decision Aid

Author
item MELLBYE, M - OSU
item SILBERSTEIN, T - OSU
item GINGRICH, G - OSU
item Pfender, William

Submitted to: Seed Production Research at Oregon State University
Publication Type: Experiment Station
Publication Acceptance Date: 2/20/2008
Publication Date: 4/1/2008
Citation: Mellbye, M.E., Silberstein, T.B., Gingrich, G.A., Pfender, W.F. 2008. The Effect of Fungicide Applications on Seed Yield in Perennial Ryegrass, and Evaluation of the Rust Model Decision Aid. Seed Production Research at Oregon State University. 127:46-48.

Interpretive Summary: Experiments in commercial perennial ryegrass seed fields were conducted to evaluate the use of the USDA-ARS stem rust model to optimize fungicide timing in management stem rust disease. The experimental plots were large enough that typical grower equipment could be used for harvesting. Fungicide applications were scheduled either by standard (calendar-based) methods, or by reference to the stem rust epidemic model which is accessible on an internet website. The experiment was conducted at two different locations. At one location, the model indicated a 2-spray program, and the timing of the sprays gave a better yield result than the standard 2-spray program that used the same fungicide. At the other location the model indicated that no sprays were necessary, whereas the standard program used one spray. There was no yield difference, which means that the rust model saved a spray at no yield cost at tis location. For both locations, use of the model gave a better economic return than the standard method for determining spray scheduling.

Technical Abstract: Experiments in commercial fields of perennial ryegrass grown for seed were conducted to assess stem rust development and seed yield in perennial ryegrass receiving different fungicide treatments. The check treatment received no fungicide, standard treatments received fungicide applications that varied by material but not timing, and a "model" treatment received fungicide applications with timing determined by reference to the ARS stem rust model that is available on an internet website. Each replicate plot was 24 X 300 ft in size, to allow harvest using grower equipment. A weigh wagon was used to measure seed yield from each plot. The experiment was conducted at two locations in the Willamette Valley. At one location, the model indicated a 2-spray program, and the timing of the sprays gave a better yield result than the standard 2-spray program that used the same fungicide. At the other location the model indicated that no sprays were necessary, whereas the standard program used one spray. In this case, there was no yield difference, which means that the rust model saved a spray at no yield cost at this location. The return per dollar invested thus was better for the model treatment than for the standard treatment at both locations.