Identification of Rhizopus stolonifer (Ehrenb.: Fr.) Vuill., causal agent of Rhizopus rot disease of fruits and vegetables


Hernandez-Lauzardo, A.-Niurka; Bautista-Banos, S.; Velazquez-Del-Valle, M.-Gerardo; Trejo-Espino, J.-Luis

Revista Mexicana de Fitopatologia 24(1): 65-69

2006


Rhizopus stolonifer commonly causes postharvest diseases on many fruits and vegetables. The objectives of this investigation were to evaluate the growth rate and sporulation of three strains of R.stolonifer on different media, to quantify the sporangiophores, sporangia, and sporangiospores of three strains by image analysis, determining the relative frequencies of spore shapes, and by scanning electron microscopy, to confirm their shape and ornamentation. Results indicated a better definition of mycelia, sporangia, and sporangiospores when isolates were grown on potato-dextrose-agar (PDA). Growth rate and sporulation was higher on this culture medium. Sporangiospores were mainly globose, following the ellipsoidal and angular shapes. Values of length, diameter, and area of sporangiophores, sporangia, and sporangiospores varied among isolates. Ornamentation of sporangiospores showed continuous ridges alongside the spore surface. PDA was the most adequate medium to further characterize R. stolonifer. Based on the morphological and quantitative characterization, the three isolates corresponded to R. stolonifer.