Effect of Temperature on Incidence and Severity of Anthracnose on White Bean. J. C. Tu, Research Station, Research Branch, Agriculture Canada, Harrow, Ontario N0R 1G0. Plant Dis. 66:781-783. Accepted for publication 1 December 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-781.

In southern Ontario, summer temperatures are generally favorable for infection of beans (Phaseolus vulgaris) by Colletotrichum lindemuthianum if free moisture is present on white bean foliage. Symptoms did not develop on inoculated plants held at constant temperatures of 28 and 32 C, but did if night temperatures were lowered. Symptoms readily occurred in the field because such high temperatures usually lasted only a few hours during daytime. Plants held at 28 and 32 C continuously for 2–3 days prior to inoculation were only slightly less susceptible. Increases in high day temperatures as the summer advanced prolonged the incubation period and slightly decreased disease severity.

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