Image analysis to identify teliospores of Tilletia indica
An image analysis system has been developed in United Kingdom to confirm the identification of teliospores of Tilletia indica (EPPO A2 list) in wash tests of wheat grain, as the spores can be confused with other species (e.g. T. walkeri). Before the analysis, teliospores are bleached in order to reveal additional morphological characters (spore profile and spore wall layers). Then, an image-processing software has been developed to automatically locate spores on a given image and recognize those of T. indica by calculating various specific parameters (perimeter, surface area, number and size of spines, maximum and minimum ray, aspect ratio, roundness). In preliminary tests, image analysis was able to separate T. indica and T. walkeri with an accuracy of 97%, using principal components analysis (PCA). These preliminary results showed that image analysis could be used to identify rapidly teliospores of T. indica, although further evaluation is needed using additional isolates, other species like T. horrida, and a larger number of spores.
Chesmore, D.; Bernard, T.; Inman, A.J.; Bowyer, R.J. (2003) Image analysis for the identification of the quarantine pest Tilletia indica.
Bulletin OEPP/EPPO Bulletin, 33(3), 495-499.