The combined effect of delayed application of yeast biocontrol agents and fruit curing for the inhibition of the postharvest pathogen Botrytis cinerea in kiwifruit

Application of biocontrol agents (BCAs) and use of induced host resistance for the inhibition of pathogen infection have often been examined separatel y. The present study focused on application of yeast BCAs alone and the int eraction between kiwifruit curing and BCA application for inhibition of inf ection by the pathogen Botrytis cinerea. Kiwifruit pedicels were removed at the natural abscission layer and the pedicel wound was used to evaluate ef ficacy of up to five yeast candidates, applied at increasing delay interval s after B. cinerea challenge. Other fruit were treated with combinations an d various sequences of fruit curing (incubation at 10 degrees C) and topica l yeast application. All yeast candidates conferred a significant level of biocontrol following applications made simultaneously with, or up to 96 h a fter B. cinerea inoculation. Biocontrol activity was further increased with an additive effect of BCA and fruit curing combined but only when BCA appl ication was made after 96 h of fruit curing. These results suggest that a d egree of protection of the kiwifruit could be achieved with the application of the yeast to the pedicel wound. If kiwifruit curing is initiated, host resistance mechanisms may not be specific to the pathogen, B. cinerea, sinc e the effect of epiphytic microbes used for biocontrol appear to be similar ly reduced by factors induced in the first 24-48 h of curing. (C) 1999 Else vier Science B.V. All rights reserved.