Abstract
Turfgrass researchers and golf course superintendents often rely on visual assessments to assess turfgrass growth and disease. Visual evaluation can make a unexpected subjective bias in the outcome of the assessment, depending on the experience of the evaluator or the degree of training. In this study, green up rate, coverage rate and percent diseased area were evaluated by applying image analysis program to photographed turfgrass for more accurate and reproducible investigation. The same photographic evaluation was presented to turfgrass experts who had experienced turfgrass evaluation for many years, and the results were compared with those obtained from the image analysis program. Experts evaluated the green up rate, coverage rate, and percent diseased area of turfgrass significantly different from the results of image analysis. There were also variations in the evaluated values among experts' evaluations, and the more difficult the photographic images are to calculate the acquired area, the greater the variation among individuals. The relationship between turfgrass research experience and image analysis values was not statistically correlated. However, the image analysis of turfgrass growth and disease was more accurate and reproducible than expert evaluation. Therefore, if turfgrass researchers or field managers use image analysis programs, even unskilled researchers expected be of great help in making evaluation.
Figures & Tables
Fig. 1. Digital image analysis of calibration photos. (A) Original and (B) digital image treated photos for greenup rate evaluation of plants. Red area indicates dormant leaves. (C) Original and (D) digital image treated photos for coverage rate evaluation of plants. Red area in photo D indicates soil surface. (E) Original and (F) digital image treated photos for percent diseased area evaluation of pink snow mold on creeping bentgrass ( ) putting green. Red indicates no diseased area. (G) Original and (H) digital image treated photos for percent diseased area evaluation of fairy ring on creeping bentgrass putting green. Red in photo H indicates area where turfgrass plants do not die.
