Relationship Between Fusarium virguliforme and Heterodera glycines in Commercial Soybean Fields in Wisconsin

Marburger, D., Conley, S., Esker, P., MacGuidwin, A., Smith, D. 2013. Relationship between Fusarium virguliforme and Heterodera glycines in commercial soybean fields in Wisconsin. Plant Health Progress doi:10.1094/PHP-RS-13-0107. Fusarium virguliforme (syn. Fusarium solani f. sp. glycines), the causal agent of sudden death syndrome, and Heterodera glycines, soybean cyst nematode (SCN), are economically important pathogens of soybean (Glycine max) in the Midwestern United States, including Wisconsin. In 2011 and 2012, samples submitted to a SCN detection program were assayed for SCN using a sieving/centrifugation method and for F. virguliforme using a real-time quantitative polymerase chain reaction (RT-qPCR) protocol. In 2011, 135 soil samples were submitted and H. glycines was detected in 56 samples, while 10 samples were positive for F. virguliforme. In 2012, 64 of 318 samples tested positive for H. glycines and 13 tested positive for F. virguliforme. The relationship between the occurrence of H. glycines and F. virguliforme was examined further for samples that were positive for H. glycines and/or F. virguliforme. Kendall’s tau rank correlation coefficient was – 0.59 (P < 0.01), indicating a negative association. Furthermore, the best-fitting logistic regression model that described the probability of detecting H. glycines in a soil sample based on detecting F. virguliforme confirmed the negative correlation. This result suggests that SCN and F. virguliforme do not rely on each other to colonize fields, indicating that fields heavily infested with SCN are not necessarily at greater risk of F. virguliforme colonization.