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Botryosphaeria stem blight on blueberries: effect of Vaccinium cultivar, Botryosphaeriaceae species and temperature

Smith, B. J., Miller-Butler, M. A.
Acta horticulturae 2017 no.1180 pp. 23-30
Botryosphaeria dothidea, Diplodia seriata, Neofusicoccum ribis, Vaccinium virgatum, blueberries, cultivars, growth chambers, pathogens, stem blight, stems, temperature
A detached stem assay compared the effect of temperature on Botryosphaeria stem blight lesion development on one highbush, two southern highbush and two rabbiteye blueberry cultivars following inoculation by isolates of three Botryosphaeriaceae genera. Partially-hardened, terminal stems were wounded, inoculated with one isolate each of Botryosphaeria dothidea, Neofusicoccum ribis, or Diplodia seriata, and incubated at 10, 15, 20, 25, 30, or 35°C. Lesions developed most rapidly on stems of 'Star' and slowest on stems of 'Climax', 'Tifblue' and 'Biloxi'. Stems inoculated with B. dothidea developed lesions more rapidly than stems inoculated with the other two pathogens. Lesion development was more rapid on stems incubated at higher temperatures than on stems incubated at lower temperatures. The effect of temperature on growth rates of these pathogens in culture was determined by growing each pathogen on acid potato dextrose agar in growth chambers at 10, 15, 20, 25, 30, and 35°C. After 5 days the average colony diameter of each of pathogen was least when incubated at 10°C and greatest for B. dothidea at the three higher temperatures, for D. seriata at 25°C, and for N. ribis at 30°C.