Rapid detection of fine fescue root diseases

By Ming-Yi Chou, University of Wisconsin-Madison

Summer patch is a common and devastating fungal disease of fine fescues. Many major turfgrass species are susceptible to summer patch. A more thorough description of summer patch disease and the causal agents have been previously discussed. As mentioned in the articles, summer patch can be caused by several closely related fungal species and their microscopic structures are similar making it difficult to diagnose and apply targeted treatments. A molecular assay was developed for one of the two main causal agents of summer patch (Magnaporthiopsis poae) (Zhao et al. 2012), and we just recently developed a new assay for detecting another important root pathogen of fine fescues, Magnaporthiopsis meyeri-festucae (Chou et al. 2022).

Similar to the advantages of rapid tests shown during the global pandemic, turfgrass disease management can also benefit from having pathogens detected in a rapid and user-friendly manner (Figure 1). Improved from the most commonly used molecular assays for pathogen identification such as PCR, a rapid detection for Magnaporthiopsis meyeri-festucae was developed using the method called Recombinase Polymerase Amplification (RPA). Unlike a standard PCR test, this RPA procedure amplifies the pathogen DNA marker under a constant temperature of 100-104˚F, and thus requires no sophisticated laboratory equipment and takes as short as 35-40 minutes from sample to results.

PCR tubes, the negative samples show no fluorescence and the positive samples do show fluorescence.
Figure 1. RPA assay consistently detected summer patch causal agent Magnaporthiopsis meyeri-festucae in hard fescue root in three replications. The bright green fluorescence indicates positive detection.

Visualization of the RPA result can be improved by incorporating a tool like the lateral flow strip, which will give you the familiar strip indicators in the rapid COVID test or in pregnancy test kits. Additional rapid testing for beneficial microbes for turfgrass seeds producers is also on our horizon. We hope this rapid testing assay can be seamlessly leveraged in the field for a proactive turfgrass management in different turfgrass sectors.


Zhao S., Clarke B.B., Shen Q., Zhang L., Zhang N. 2012. Development and application of a TaqMan real-time PCR assay for rapid detection of Magnaporthe poae. Mycologia 104:1250-1259.

Chou M.Y., Luo J., Clarke B.B., Murphy J.A., Zhang N., Vines P., Koch P.L. 2022. Rapid detection of the recently identified turfgrass pathogen Magnaporthiopsis meyeri-festucae using recombinase polymerase amplification. Plant Disease.