Effect of Dew Period and Temperature on Infection of Seedling Maize Plants by Puccinia polysora. C. A. Hollier, Former Graduate Research Assistant, Department of Plant Pathology and Weed Science, Mississippi State University, Mississippi State 39762. S. B. King, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, P.O. Drawer PG, Mississippi State, MS 39762. Plant Dis. 69:219-220. Accepted for publication 27 August 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/PD-69-219.

The effect of dew period (0–16 hr at 4-hr increments) and temperature (8–40 C) on infection of maize (Zea mays) seedlings by Puccinia polysora was determined. Dew was always necessary for infection, and no infection occurred at temperatures of 8, 12, 36, or 40 C, regardless of length of dew period. A 16-hr dew period at 26 C was the optimum environment for infection and resulted in more than double the pustule density obtained with a 12-hr dew period. Lower temperature limits for infection were 16 C for the 12- and 16-hr dew periods and 18 C for the 4- and 8-hr dew periods. Upper temperature limits for infection were 22, 28, 32, and 32 C for the 4-, 8-, 12-, and 16-hr dew periods, respectively.