A simple method for conidial production and establishing latent infections of apples by Phlyctema vagabunda (syn: Neofabraea alba)

Abstract

A method was developed to inoculate and establish infection of detached apple ruit with the bull's eye rot pathogen, Phlyctema vagabunda (syn: Neofabraea alba), without wounding. Mycelial cultures of P. vagabunda did not produce conidia on commonly used potato dextrose agar, or several other tested media. Growth on corn meal agar resulted in the highest conidial yield, and maximum production was achieved after 5 days. These conidia were placed on water agar, and apple fruit were placed on these spores for at least 5 days for establishment of infections. Reliable infection of 66-100% of apples required 14 days of contact. The ability to rapidly produce copious quantities of conidia and inoculate without wounding facilitates a number of other postharvest control and epidemiology studies.