Date of this Version
Five-year-old 'Collins' highbush blueberries were treated in August with glyphosate (N-phosphonomethyl glycine) at 0.36, 3.6 and 7.2 g/liter acid equivalent as a spot treatment alone or with pruning or applying paraquat (1, 1'-dimethyl-4, 4'-bipyridinium ion) at 1.2 g/liter to remove green tissue prior to glyphosate application. Initial response was terminal dieback of young canes. Symptoms the following spring included additional terminal dieback, leaf and cane morphological aberrations, and elongation of the flower corolla. One year after treatment, regrowth was normal. There was no effect on blueberry yield the season following treatment.