Effect of different temperature and culture media on the growth of Macrophomina phaseolina.

The charcoal root disease caused by Macrophomina phaseolina (Tassi) Goidanich may cause considerable damages in hot as well as in dry seasons. The effect of temperature and culture media were studied on the growing patterns of 35 M. phaseolina isolates, collected from different districts of Hungary. The isolates were grown at 10, 15, 20, 25, 30, 35 and 40 degrees C temperatures respectively, and additionally at 25 degrees C on potato-dextrose-, malt-extract-, Czapek-Dox-, Sabouraud-glucose-, maize-flour- and watery agar media, using 90 mm Petri-dishes, 4 repetitions in each case. For all the isolates the most favourable temperature regime was 25 to 35 degrees C and the most advantageous media was the malt-extract-, Sabouraud-glucose- and potato-dextrose-agar media. At these conditions (temperatures and culture media) mycelia growth and the diameter of microsclerotial colonies reached the 90 mm at the 5th day. Mycelia growth of the pathogen was very low at 10, 15 and 40 degrees C, and did not form microsclerotia. On watery agar microsclerotial colony seldom developed, it needed 14 days, and no continuous mycelia developed even in a 8th months culture. Diameter of microsclerotia measured on different culture media varied between 39-308 microm.