|Authors: ||B.J. Smith, M. Miller-Butler|
|Keywords: ||Rubus, blackberry, Botrytis cinerea, gray mold, Colletotrichum spp., ripe rot, fruit quality, rosette, Cercosporella rubi|
Pre- and postharvest fruit rots, rosette, and other diseases are limiting factors of blackberry production in the southern USA. The development of cultivars with increased resistance to these diseases should result in reduced use of fungicides and greater profits for growers.
Five to nine blackberry cultivars adapted to the southeastern USA were evaluated for susceptibility to postharvest fruit diseases and quality in five trials.
Fully ripe, blemish-free berries were incubated in the laboratory for four or five days and scored for Botrytis fruit rot, ripe rot, and other fruit diseases on a visual scale: 0 = no disease symptoms to 3 = severe symptoms.
Botrytis fruit rot (gray mold) caused by Botrytis cinerea was the most common postharvest disease identified in these trials while ripe rot caused by Colletotrichum spp. was also important.
Across all the studies, 'Navaho', 'Ouachita', and 'Chickasaw' had the fewest berries with postharvest disease symptoms, while 'Shawnee' and 'Arapaho' had the highest Botrytis fruit rot scores.
Cultivars with the lowest levels of postharvest fruit diseases received good quality evaluations.
Rosette disease occurred on the plants at one location, and rosette disease severity was assessed on the cultivars in that trial.
The erect, thorny cultivars, 'Chickasaw', 'Shawnee', and 'Kiowa', had significantly more rosettes per plant than the thornless cultivars, 'Sweetie Pie', 'Navaho', and 'Apache'.
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