Location: Agroecosystems Management ResearchTitle: Fungicide seed treatments for evaluating the corn seedling disease complex following a winter rye cover crop
|ACHARYA, JYOTSNA - Iowa State University|
|ROBERTSON, ALISON - Iowa State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/14/2017
Publication Date: 6/14/2017
Citation: Acharya, J., Kaspar, T.C., Robertson, A.E. 2017. Fungicide seed treatments for evaluating the corn seedling disease complex following a winter rye cover crop. In: Proceedings of American Phytopathological Society North Central Division Meeting, June 14-16, 2017, Champaign, Illinois.
Technical Abstract: Seed treatments have been used to manage corn seedling diseases since the 1970’s and they contain a combination of active ingredients with specificity towards different pathogens. We hypothesized that using different seed treatment combinations and assessing seedling disease incidence and severity would enable us to better understand corn-seedling disease pathosystem in the winter rye cover crop corn-cropping system. We conducted a growth chamber experiment using field soil with seed treatments containing a single fungicide active ingredient or combinations of active ingredients that included: ALL =combination of metalaxyl, pyraclostrobin, fludioxonil, ipconazole, and sedaxane (controls Pythium spp., Fusarium spp. and Rhizoctonia solani); P =metalaxyl (controls Pythium spp. only); FR =combination of pyraclostrobin, fludioxonil, ipconazole, and sedaxane (controls Fusarium spp. and Rhizoctonia solani); FP =Combination of metalaxyl and pyraclostrobin (controls Fusarium and Pythium spp.); NF =non treated. Treated and non-treated seeds were planted 3 days after rye termination in cups with (R) or without rye (NR) and then grown at 12 C. Corn plants were then evaluated for disease incidence. In general, seed treatments effective against Pythium species showed the greatest emergence, shoot height, and the least radicle rot severity when corn followed cereal rye. Species of P. irregulare and P. torulosum and F. oxysporum, F graminearum, and F. solani were the most prevalent species identified morphologically from diseased corn roots. Data from this study support earlier studies that Pythium species play a major role in the corn seedling disease complex in the winter rye corn cropping system. Further research should help to identify seed treatments that will be effective in reducing the risk of corn seedling diseases following a cereal rye cover crop.