Abstract “Bartlett” pear fruits were inoculated at weekly intervals with three fungi (Penicillium
expansum Botrytis cinerea and Dothiorella gregaria). Susceptibility of the fruit was assessed
by following lesion growth. Very young fruits resisted fungal development. When fruits had
reached approximately one-third of full size (8 weeks after full bloom) lesion development
occurred. Penicillium expansum was first to develop and grew most rapidly at all stages of
pear maturity but fruit resistance to the development of all three pathogens declined steadily …

MATERIALS AND METHODS Cultures and inoculation of fruit Cultures of B. cinerea Pers. ex
Fr., D. gregaria Sacc. and P. expansum Link were obtained from Dr NF Sornmer,
Department of Pomology, University of California, Davis. Dothiorella gregaria and P.
expansum were maintained on potato dextrose agar at room temperature. Botrytis cinerea
was cultured on V-8 juice agar [20] also at room temperature. Under these conditions only B.
cinerea and P. expansum produce spores. The spores were harvested according to …