VIEW ARTICLE

Stimulation of Geotrichum candidum by Low Oxygen and High Carbon Dioxide Atmospheres. John M. Wells, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, P. O. Box 87, Byron, Georgia 31008; Donald H. Spalding, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, 13601 Old Cutler Road, Miami, Florida 33158. Phytopathology 65:1299-1302. Accepted for publication 11 June 1975. DOI: 10.1094/Phyto-65-1299.

Average in vitro growth of four isolates of Geotrichum candidum in a buffered asparagine-yeast extract broth at 21 C was as great or greater in 1 or 3% O₂ atmospheres, with or without 3% CO₂, as in air. In an atmosphere of 3% O₂ with 3% CO₂ average growth in 24 hours was about twice that of air. Growth decreased linearly with decreasing O₂ concentrations below 3%. At concentrations of 3% or more, CO₂ repressed growth of G. candidum in the presence of 21% O₂. In a low O₂ atmosphere, however, 30% CO₂ was necessary to repress growth. Percent decay of tomatoes inoculated with G. candidum in the green, pink, and red stages of ripeness was significantly greater in the atmospheres of 3% O₂, with or without 5% CO₂, than in air. Decay development was inhibited in 0.25% O₂ with 5% CO₂; however, this concentration of O₂-injured tomatoes.