Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/4/2000
Publication Date: 12/20/2004
Citation: Smith, B.J. 2004. Susceptibility of southern highbush blueberry cultivars to Phytophthora root rot. Meeting Abstract. p.3
Technical Abstract: Phytophthora root rot, caused by Phytophthora cinnamomi Rands, is a serious disease of highbush blueberry (Vaccinium corymbosum L.) especially in wet, poorly drained soils. Rabbiteye blueberry (RE)(V. ashei Reade) cultivars commonly grown in the southeastern U. S. are less susceptible to this disease. Southern highbush cultivars (SHB) are hybrids between V. corymbosum and various 'southern' blueberry species. The acreage of SHB blueberry cultivars is increasing, and therefore, so is the potential threat of Phytophthora root rot. This study was initiated in 1995 to compare the susceptibility of 7 SHB cultivars and 2 RE cultivars to P. cinnamomi and to evaluate the effect of bed height (raised and flat) and fungicide treatments on disease severity. Two-year-old blueberry plants were transplanted in soil naturally infested with P. cinnamomi. After two years, root rot symptoms were evident throughout the field, but there were no significant differences in disease severity or plant vigor due to bed height or fungicide treatment. There were differences among cultivars. The RE cultivars were more vigorous than SHB. Gulfcoast and Reville were the most vigorous of the SHB. After five years, 90% of Gulfcoast and 75% of Tifblue (RE) plants still were alive, whereas, only 7% of the Misty (SHB) plants had survived. These results indicate that at least one SHB cultivar, Gulfcoast, has field resistance to Phytophthora root rot equivalent to RE blueberry cultivars, but other SHB cultivars are susceptible to this disease.