Control of postharvest decay in pear by four laboratory-grown yeasts and two registered biocontrol products

Control of blue mold decay in Bose pears was studied with the laboratory-gr own yeasts Rhodotorula glutinis, Cryptococcus infirmo-miniatus, and two str ains off Cryptococcus laurentii, as well as registered biocontrol products Aspire, containing the yeast Candida oleophila, and Bio-Save 11 (now Bio-Sa ve 110), containing the bacterium Pseudomonas syringae. Both thiabendazole (TBZ)-sensitive and TBZ-resistant strains of Penicillium expansum were used . Aspire treatment reduced the average lesion diameter by approximately 65 and 45%, and reduced decay incidence by 27 and 9% with TBZ-resistant and TB Z-sensitive expansum, respectively in the first year of the study, but did not result in significant decay control in the second year. Bio-Save 11 red uced decay lesion,diameter by 32 to 72% and incidence by 21 to 40% over the 2 years. In both years, TBZ-sensitive P. expansum was completely controlle d by the combination of either C. laurentii (both strains), A. glutinis, or C. infirmo-miniatus with 100 ppm TBZ. With TBZ-resistant P. expansum, cont rol of wound infection with these yeasts alone or with 100 ppm TBZ ranged f rom 62.9 to 100%. In a packinghouse trial, control by Bio-Save 110 + 100 pp m TBZ and Aspire + 100 ppm TBZ was not different than control by TBZ at 569 ppm, the maximum label rate. The amount of decay following Aspire + 100 pp m TBZ treatment was significantly less than the amount of decay following B io-Save 110 + 100 ppm TBZ treatment.