Submitted to: National Berry Fruit Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/27/1998
Publication Date: N/A
Technical Abstract: The susceptibility of blueberry flowers at various developmental stages was evaluated by inoculating potted blueberry bushes of the rabbiteye cultivars, Climax, Premier and Tifblue, and the southern highbush cultivars, Magnolia and Jubilee, during bloom with a conidial suspension of Botrytis cinerea. Inoculated plants were then incubated in a dew chamber for two days at 20 oC and 100% RH. Flower stage was rated at the beginning of each study and two weeks after inoculation. Botrytis disease symptoms were scored two weeks after inoculation on a visual scale of 0 to 7. 'Jubilee' and 'Premier' had the lowest disease severity scores when averaged over flower stages; while 'Tifblue' had higher disease scores than 'Magnolia' and 'Climax'. The three southern highbush cultivars did not differ as a group in their susceptibility to Botrytis blossom blight from the two rabbiteye cultivars. Susceptibility to Botrytis blossom blight was greatest at later flower stages. Buds inoculated at stage 1 through stage 3 (prebloom) developed fewer disease symptoms, while flowers inoculated at stages 5 to 7 (full bloom) developed more sever symptoms. 'Premier', 'Tifblue', and 'Magnolia' flowers at stage 6 were very susceptible. Since susceptibility of blueberry flowers is greatest at or near full bloom, fungicide applications for Botrytis blight control of southern blueberries should be made beginning at flower stage 4 and continue through stage 6.