Semi-selective medium for recovery and quantification of Cryptosporiopsis perennans from apple fruits

摘要

> face="Verdana, Arial, Helvetica, sans-serif" size="2">Bull's eye rot, caused by Cryptosporiopsis perennans, is one of the most important apple's posharvest diseases in Brazil. The aim of this research was to develop and evaluate a semi-selective media to recovery and quantification of the epiphytic population of C. perennans on the apple fruit surface. A PDA medium amended with tetracycline, nistatine and iprodione in concentrations of 12.5; 1 and 1 size="2">µ face="Verdana, Arial, Helvetica, sans-serif" size="2">g i.a.mL-1, respectively, allowed the development of C. perennans colonies statistically similar (P0.05) to those in PDA media. Nistatine concentrations higher than 1 size="2">µ face="Verdana, Arial, Helvetica, sans-serif" size="2">g.mL-1 inhibited the growth of the pathogen. Under natural infection conditions and pre-inoculation with C. perennans, the media allowed the detection and quantification of the fungal population on the fruit surface without affecting C. perennans development. Number of conidia observed in pre-inoculated fruits was correlated (r=0.88; P0.05) to inoculum concentration sprayed on the fruit surface.