Infectivity of Conidia of Peronospora hyoscyami After Storage on Tobacco Leaves. Y. Cohen, Professor, Department of Life Sciences, Bar-Ilan University, Ramat-Gan 52100, Israel. H. Eyal, Senior Technician, Department of Life Sciences, Bar-Ilan University, Ramat-Gan 52100, Israel. Plant Dis. 68:688-690. Accepted for publication 6 February 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-688.

Conidia of the blue mold fungus Peronospora hyoscyami were stored, either attached to infected leaves or detached and settled on healthy tobacco leaves, at various temperatures and relative humidities (RH) and assayed for infectivity to tobacco plants. Attached conidia retained a high level of infectivity after 113 days at 15±3 C when stored at about 20% RH but lost infectivity within 9 days when stored at about 90% RH. Detached conidia retained infectivity for a relatively short period—9 days at 10 C and 2 days at 30–33 C.