VIEW ARTICLE

Effect of Relative Humidity and Temperature on Needle Cast Disease of Douglas Fir. A. K. Parker, Research Scientist, Department of Fisheries and Forestry, Forest Research Laboratory, Victoria, British Columbia, Canada. Phytopathology 60:1270-1273. Accepted for publication 23 March 1970. DOI: 10.1094/Phyto-60-1270.

High levels of infection by Rhabdocline pseudotsugae subsp. pseudotsugae occurred on Douglas fir in growth chamber experiments when a treatment of 100% relative humidity and 13 C was applied for 3 days immediately following inoculation. Infection levels were lower when the treatment was applied at higher temp or for less than 3 days. After the 3-day treatment period, temp did not affect significantly the level of infection.