Clemson University and University of Georgia scientists developed an agar-based assay called the lipbalm tube assay (Amiri et al. 2008, .pdf; Amiri et al. 2009, pdf) to determine location-specific resistance profiles in Monilinia fructicola. ‘Profile’ was featured in "The Grower" magazine in 2008 (.pdf, 118 KB) and the 'American Fruit Grower' magazine in 2009 (URL). It determines the sensitivity of local Monilinia populations to the three most commonly used fungicide classes (DMIs, BZIs, and QoIs) and identifies the most effective spray program for brown rot control based on location-specific resistance profiles. In addition, ‘Profile’ counteracts selection of pathogen populations for fungicide resistance, making disease management and the entire operation more sustainable for the future.
The situation in South Carolina is similar. Fungicide resistance is present in the main production areas. In 2009 we anticipated an epidemic from brown rot but it did not happen, likely because we identified high risk areas with the Profile kit and growers implemented crucial changes to their spray program, such as higher doses of fungicides or switching to a mode of action that works better. I would estimate that we would have lost about 10%-15% of our total production (includes pre and postharvest losses) if the Profile monitoring program had not been used. We total about $70 million annually, so the savings would be anywhere from $7 to $10.5 million (Dr. Guido Schnabel, Clemson University).
Profile - An Agents Perspective: "The profile kit was very easy to use and provided a timely response to suspected resistance problems. Problems were easily identified by viewing the petri dishes. This past year we did have some trouble finding enough fruit to have an accurate sample. Bacterial contamination is a definite possibility if you are not careful in your procedure. Whatever you do, don't forget to check it on time. Some of the contaminants grow very quickly and can cloud results if not viewed when they are supposed to be. All in all the system works but will take up some of your time getting used to the procedure." -Andy Rollins, County Agent, Piedmont SC.