Thermal Changes in Tall Fescue…

Thermal Changes in Tall Fescue Associated with Rhizoctonia Solani Infection

By Caleb Henderson and David McCall, Ph.D.

Tall fescue (Festuca arundenacea) is one of the most ubiquitous grasses found in residential lawns, greenspaces, and pastureland throughout the cool season and transition zones of the United States. Rhizoctonia solani, the causal agent of brown patch, is among the most common pathogens on tall fescue causing loss of aesthetic quality and turfgrass stand thickness. Treatment for brown patch is widely available and effective treatments in residential areas are typically applied reactively where treatment is applied after symptoms manifest in a given area. By this point the pathogen has had ample time to decimate the turfgrass stand which may require weeks to be restored to pre-disease quality. It has been suggested previously that pathogen stress can cause changes in thermal images. With this information we looked at the early days of infection of R.solani on tall fescue. Tall fescue stands were infected with varying amounts of inoculum and thermal images were taken daily for the first ten days. Infected stands showed significantly higher relative temperature changes on a 2-day average than noninoculated stands (p=0.035). This preceded the onset of visual symptomology suggesting that thermal imagery could be useful in pre-symptomatic detection of pathogen infection.

Field validation of brown patch detection on tall fescue using thermal imagery.

Photo courtesy of Caleb Henderson