Title: Effect of Fungicide Seed Treatments on Fusarium virguliforme and Sudden Death Syndrome of Soybean Authors
Submitted to: American Pathological Society North Central Division Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 7, 2010
Publication Date: June 8, 2010
Citation: Weems, J.D., Zhang, G.R., Ames, K.A., Haudenshield, J.S., Hartman, G.L., Bond, J.P., Bradley, C.A. 2010. Effect of Fungicide Seed Treatments on Fusarium virguliforme and Sudden Death Syndrome of Soybean [abstract]. American Pathological Society North Central Division Annual Meeting, June 6-8, 2010, Rapid City, South Dakota. CD ROM. Technical Abstract: Sudden death syndrome (SDS) is a yield reducing disease increasing in prevalence across soybean producing states. Recent research indicates the SDS pathogen, Fusarium virguliforme, can infect as early as initial radicle emergence. This suggests fungicide seed treatments could offer some protection against F. virguliforme during early soybean development. In 2008 and 2009, field studies across two locations and a greenhouse study were conducted to evaluate eleven fungicide seed treatments and an untreated control across moderately resistant and susceptible cultivars for effects on F. virguliforme infection and SDS development. The southern Illinois location (Valmeyer) had a natural F. virguliforme infestation, the central Illinois location (Urbana) had a natural infestation and the soil was augmented with sterilized grain sorghum colonized by F. virguliforme, and the greenhouse study was infested with the sterilized grain sorghum colonized by F. virguliforme. Quantitative polymerase chain reaction (qPCR) was used to measure F. virguliforme DNA concentrations present in V1 taproot samples. Root samples collected at three times during the season were digitally scanned and analyzed using specialized software (WinRHIZO) to measure root disease symptoms. Foliar SDS symptoms were rated throughout plant growth and harvest data were collected. Fungicide seed treatments had no significant effect on F. virguliforme DNA concentration within roots. According to the root scan analyses, four seed treatments provided an increased number of root tips compared to the untreated control at one root collection timing. At the Valmeyer location, most seed treatments reduced early disease development compared to the untreated control; however, treatments had no effect on final disease severity. No significant differences were observed among treatments for yield. In general, fungicide seed treatments had little to no effect on SDS in our research trials.