VIEW ARTICLE

Influence of Air Temperature on Brown Stem Rot of Soybean. D. V. Phillips, Assistant Professor, University of Georgia, College of Agriculture Experiment Stations, Georgia Station, Experiment, Georgia 30212; Phytopathology 61:1205-1208. Accepted for publication 14 May 1971. DOI: 10.1094/Phyto-61-1205.

The influence of air temperature on brown stem rot (BSR) of soybean was determined, using several soybean cultivars inoculated with different isolates of Cephalosporium gregatum. Maximum BSR symptom development occurred from 15 to 27 C. Symptom development, rated on a scale of 0-4, was 3.0 at 27 C, 2.0 at 30 C, and 1.0 at 32 C. Cultivars were about equally susceptible to BSR, but C. gregatum isolates differed in virulence. The influence of temperature was the same regardless of cultivar or isolate. Air temperatures in field microplots were high enough to seriously limit BSR development for only a minor part of the growing season, and BSR development in these plots was extensive. Thus, air temperatures may have little influence on BSR development in the field.