VIEW ARTICLE

Influence of Culture Age and Temperature on Germination of Helminthosporium sorokinianum Conidia and on Pathogenicity to Poa pratensis. Clinton F. Hodges, Associate Professor of Horticulture and Agronomy, Departments of Horticulture and Agronomy, Iowa State University, Ames 50010; Phytopathology 62:1133-1137. Accepted for publication 10 April 1972. DOI: 10.1094/Phyto-62-1133.

Conidia of Helminthosporium sorokinianum germinated in larger numbers, at a faster rate, and produced more and longer germ tubes and germ tube branches as temperature was increased from 10 to 22 C; above 22 C, percentage germination and growth rates of germ tubes declined. Conidia from older cultures germinated faster and in larger numbers and produced more and longer germ tubes and germ tube branches at all temperatures. However, conidia from older cultures were less pathogenic to Poa pratensis than were conidia from younger cultures.