Efficiency of Gamma Irradiation on Conidial Germination and Mycelial Growth of Botrytis allii

Abstract

ABSTRACT Aerial dispersal of inoculum is considered to be an important factor in the epidemiology of many plant diseases. Discarding of untreated onion (Allium cepa L.) bulbs infected with the pathogen Botrytis allii Munn (Syn. B. aclada Fres) can increase the inoculum pressure and infect healthy plants in neighboring fields. A technique to suppress fungal development is needed. Doses of gamma radiation from 1 to 5 kGy were tested on the survival these conidia and mycelial development under laboratory conditions. Conidia were placed on water agar after exposure in closed Petri dishes for 24 h. Results showed that germinability of conidia exposed to gamma irradiation was reduced up to 99% at 5kGy, whereas, germinability of conidia that were not exposed did not decrease significantly. Mycelia exposed to gamma radiation had significantly decreased growth of up to 98% at 4 kGy. Gamma irradiation might be exploited in the treatment of infested onion residues to decrease the inoculum load in the environment.