First Report Of Verticilliunz Dahliae Causing Dieback Of Highbush Blueberry (Vaccinium Corymboszan) In Oregon And Washington

In the spring of 2011, 2013, 2015 and 2016, ‘Aurora’, ‘Blue Ribbon’, ‘Bluetta’ and ‘Cargo’ blueberry plants (Vaccinium corymbosum L.) from Oregon and Washington were sent to the Oregon State University Plant Clinic for diagnosis. Symptoms included foliar chlorosis, reddening, blackening of either part or the entire stem, followed by stem dieback, vascular discoloration in the lower stems, and occasional wilt. The diseased plants were scattered in the fields, with incidence ranging from less than 5% to 40% of total acreage. Isolations were made from surface-disinfected de-barked stems and crown tissues to water agar and potato dextrose agar. Verticillium dahliae Kleb. was recovered from stems and crowns of all four cultivars, from which single-spore isolates were derived. Morphology of the conidiophores, conidia and microsclerotia fit the description for V. dahliae (Klebahn 1913). Two of the isolates (OSU herbarium #OSC# 156080 and #OSC# 156081) were first identified by multiplex PCR assay (Inderbitzin et ...