Effect of Temperature and Wetness on Infection of Black Raspberry by Aeciospores of Arthuriomyces peckianus. D. L. Truxall, Graduate Assistant; Department of Plant Pathology, The Pennsylvania State University, University Park 16802. J. W. Travis, Associate Professor, and K. D. Hickey, Professor, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. Plant Dis. 79:805-808. Accepted for publication 24 April 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0805.

The optimum temperature range and leaf wetness duration for germination and infection of black raspberry by aeciospores of Arthuriomyces peckianus were determined experimentally. The germination of aeciospores on water agar increased with temperature from 12 to 28°C. Maximum germination of aeciospores occurred in free water and declined as relative humidity was reduced below 100%. The effect of temperature on the ability of aeciospores to infect leaf disks of black raspberry was described by the model y = - 171.688 + 21.609T- 0.544T2, where y = percent successful infection of aeciospores and T = temperature (C). The predicted optimum temperature for infection was 19.9°C. The optimum duration of leaf wetness for infection was 10 h at 22°C, but infection could occur in as little as 6 h at 22°C.