Effects of Temperature and Light on Development of Anthracnose on Alfalfa. Ronald E. Welty, Research Plant Pathologist, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, and Department of Plant Pathology, Raleigh 27650. John O. Rawlings, Professor, Department of Statistics, North Carolina Agricultural Research Service, Raleigh 27650. Plant Dis. 64:476-478. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/PD-64-476.

Anthracnose was more severe in susceptible plants incubated at 24 C than at 16 C. Differences in disease severity were not significant among susceptible plants incubated at light/dark temperatures ranging from 14/10 C to 30/26 C after a 3-day infection period at 16 C or 2 and 3 days at 24 C. The severity of anthracnose was similar in susceptible cultivars Team and Saranac infected at either 16 or 24 C. Anthracnose severity was similar in resistant cultivars Arc, Vangard, and Saranac AR when the temperature during infection was 16 C but was more severe in Saranac AR when the temperature during infection was 24 C. Disease severities of susceptible plants incubated in 1,600, 6,500, and 24,800 lux during the infection period were not statistically different.