A Statistical Evaluation of Methods of In-Vitro Growth Assessment for Phyllosticta citricarpa: Average Colony Diameter vs. Area

Fungal growth inhibition on solid media has been historically measured and calculated based on the average of perpendicular diameter measurements of growth on fungicide amended media. We investigated the sensitivity of the calculated area (DA) and the measured area (MA) for assessing fungicide growth inhibition of the ascomycete, Phyllosticta citricarpa on solid media. Both the calculated, DA and the actual measured area, MA were adequate for distinguishing significant treatment effects of fungicide on fungal growth, however MA was more sensitive at identifying significant differences between the controls and fungicide concentrations below 5 ppm.