Morphological and physiological characterization of Macrophomina isolates from Senegal

The pathogen Macrophomina phaseolina (Tassi) Goid. is a monotypic species with broad host range estimated at more than 500 species in 75 families. Morphological, physiological, pathological, and genetic characteristics of 104 isolates from Senegal were studied. The molecular study revealed the presence of a new species of Macrophomina named M. pseudophaseolina. In this chapter, we synthetize results of morphological and physiological activities. Morphologically, M. phaseolina is very similar to M. pseudophaseolina. We observed an identical growth rate of the two species at the temperature 36°C with colonies that reached 9 cm in diameter after 3 days of incubation. Macroscopic characterization of the fungi, based on the color and appearance of mycelium, allowed to distinguish isolates of blackish and grayish color, while microscopic observation shows variability in shape of black colored sclerotia, some of them being circular, and others irregular. Comparing sclerotial weight of the two species, those of M. pseudophaseolina were generally heavier.