A comparative study of Phomopsis anacardii and Phomopsis mangiferae isolates by pathogenicity and nutrition of C and N, under three light systems.
Gurgel L. M. S., Menezes M., Coêlho R. S. B.
Author Affiliation: UFRPE, Depto. de Agronomia, Área de Fitossanidade, Rua Dom Manoel de Medeiros, s/n, Dois Irmãos, CEP 52171-900, Recife/PE, Brazil.
Summa Phytopathologica 28 : 160-166
Abstract : Isolates of P. anacardii and P. mangiferae were studied for cross-pathogenicity and the effect of different sources of carbon (C) and nitrogen (N) on mycelial growth, pycnidia production and sporulation. In the pathogenicity analysis, all isolates were pathogenic when inoculated on cashew and mango leaves, showing symptom intensity variation, mainly the Pa2 and Pm4 isolates. For the physiological characterization of the isolates, the effect of four N sources (asparagine, arginine, ammonium sulfate and potassium nitrate) and four C sources (starch, glucose, maltose and sucrose) were tested under three light systems (continuous light, alternating light/dark and continuous dark), for ten days at 25°C. For most of the isolates, among the N sources used, asparagine and potassium nitrate, when combined with starch, glucose or sucrose, under continuous light conditions, induced the best mycelial growth, pycnidia and spore production. Considering the different physiological processes, P. anacardii showed a better performance than P. mangiferae under continuous light conditions.