THE ACTIVATION OF LATENT INFECTIONS OF MONILINIA-FRUCTICOLA ON APRICOTS BY VOLATILES FROM THE RIPENING FRUIT

Latent infections produced by Monilinia fructicola on green apricot fruit are separated from aqueous contact with live host tissues by hydrophobic suberin. However, they respond to host ripening and become invasive. The time and intensity of production of the volatile compounds acetaldehyde and ethanol during fruit ripening strongly correlated with both the invasive outbreak of mycelium from arrested lesions, and with the stimulation of growth of germ tubes in vitro in the presence of fruit volatiles. Latent infections on green apricots were activated to escape from the lesions in response to exposure to those volatiles in the concentration detected from ripe apricots. However, the tissue of green apricots was stimulated to fresh necrosis and general fruit invasion did not occur.