A BACTERIAL LEAF-SPOT OF HIGHBUSH BLUEBERRY HARDWOOD CUTTINGS CAUSED BY PSEUDOMONAS-ANDROPOGONIS

A leaf spot has been observed for several years on nursery-grown blueb erry cuttings throughout southern New Jersey. A bacterium that produce d a white-pigmented colony on yeast extract-dextrose-calcium carbonate agar and was nonfluorescent on King's B agar was repeatedly isolated from lesions on diseased leaves collected from various locations. The bacterium was identified as Pseudomonas andropogonis using diagnostic tests, Biolog, and fatty acid analysis. Infiltration of bacterial susp ensions at concentrations of 10(6) and 10(8) cells per mi into leaves of 3- to 5-year-old potted plants and 1-year-old hardwood cuttings res ulted in the appearance of necrotic lesions similar to leaf spot sympt oms observed on plants in the field. The bacterium was reisolated from the necrotic lesions produced by these inoculations. Inoculation of b lueberry isolates into cranberry leaves also caused pathogenic respons es. This is believed to be the first report of a bacterial leaf spot o n Vaccinium species.