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Bougainvillea Blight, a New Disease Caused by Phytophthora parasitica. S. A. Alfieri, Jr., Plant Pathologist, Division of Plant Industry, Florida Department of Agriculture and Consumer Services, Gainesville 32601. Phytopathology 60:1806-1808. Accepted for publication 20 July 1970. DOI: 10.1094/Phyto-60-1806.

A foliar blight of Bougainvillea was observed for the first time in 1968 in Fort Myers, Florida. Isolations from infected leaves and blossoms yielded Phytophthora parasitica, which was shown to be the causal agent of the foliar blight. Lesions occur as small, irregular, ashy-green hydrotic spots, usually starting at the tips and margins of the younger leaves. As the lesions enlarge and darken, the leaves become limp, blackened, and curled. Symptoms on floral bracts are tan lesions of collapsed tissue having a reticulate appearance. The fungus often invades the petiole and stems, resulting in blackened, drooping branch tips. Older, mature leaves were never infected, and appear to be immune. Two cultivars of tomato were susceptible and produced symptoms similar to those on Bougainvillea. Of the four Bougainvillea cultivars tested, Sanderiana (purple) was highly resistant; After Glow, moderately resistant; and Barbara Karst and Gold, highly susceptible. Daconil 2787 was most effective, captan moderately effective, and fixed basic copper sulfate (53% metallic) least effective in disease control.