VIEW ARTICLE

Ecology and Epidemiology

Effects of Temperature on Sporulation, Conidial Germination, and Infection of Maize by Peronosclerospora sorghi from Different Geographical Areas. M. R. Bonde, Research plant pathologist, U.S. Department of Agriculture, Agricultural Research Service, Plant Disease Research Laboratory, Ft. Detrick, Building 1301, Frederick, MD 21701; G. L. Peterson(2), and N. B. Duck(3). (2)(3)Biological laboratory technician, and student trainee, respectively, U.S. Department of Agriculture, Agricultural Research Service, Plant Disease Research Laboratory, Ft. Detrick, Building 1301, Frederick, MD 21701. Phytopathology 75:122-126. Accepted for publication 30 July 1984. 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, 1985. DOI: 10.1094/Phyto-75-122.

Five isolates of Peronosclerospora sorghi (two from the United States, and one each from India, Brazil, and Thailand) were compared for effects of dew-period temperature on sporulation, germination, germ-tube growth, and establishment of infection in maize. Responses of all isolates except that from Thailand were similar at each air temperature. The isolate from Thailand was more tolerant to high temperatures; it germinated optimally from 12 to 32 C, whereas the Indian, Texas, and Brazilian isolates germinated optimally from 12 to 20 C. All isolates sporulated optimally from 15 to 23 C. The Thailand isolate was the only one that produced mature conidia at 26 C. Each isolate following conidial inoculation caused high levels of systemic infection at temperatures from 15 to 32 C, and moderate levels at temperatures as low as 10 C, during the dew period.