Fusarium virguliforme and corn: exploring temporal field dynamics within an asymptomatic host
Amy Baetsen-Young: Michigan State University
<div>The asymptomatic host range of <em>Fusarium virguliforme</em> (<em>Fv</em>) includes corn, a common crop rotation with soybean. We tested the hypothesis that corn may serve as an important asymptomatic host reservoir for <em>Fv</em> the causal agent of soybean sudden death syndrome, altering <em>Fv</em> population dynamics, and management. The objective of this study was to determine the temporal dynamics of corn root colonization by <em>Fv. </em>Experiments were conducted in IA, IN, and MI for two years, and in WI for one year. Corn roots were sampled at 1, 2, 4, 8, 12, and 16 weeks after planting (WAP) in MI, and 4 or 5, 8 and 16 WAP for IA, IN, and WI. DNA was extracted and analyzed by real-time qPCR for <em>Fv</em> quantification. Trials were inoculated with <em>Fv</em> and contained four cultural treatments (four replicates/treatment) of 1) tillage with corn residue, 2) tillage without corn residue, 3) no-tillage with corn residue, and 4) no-tillage corn with no residue. In 2016, low (ca. 100 fg/10 mg root tissue) <em>Fv</em> DNA quantities were detected at 1, 2, and 4 WAP in the MI corn, and dropped to below limits of detection at 8 WAP, followed by a gradual increase at 12 and 16 WAP. In 2017, a similar trend was observed in MI, and in trials in IA and IN; however, higher levels of <em>Fv</em> DNA was detected across sampling time points. Overall, trials in MI, IA, and IN revealed consistent low-level detection of <em>Fv</em> in corn roots. Cultural tillage practices showed inconsistent treatment effect between trials and locations.</div>
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