VIEW ARTICLE

Ecology and Epidemiology

Effects of Spore Concentration, Temperature, and Dew Period on Disease of Field Bindweed Caused by Phoma proboscis. Dana K. Heiny, Postdoctoral research associate, Department of Plant Pathology, University of Arkansas, Fayetteville, 72701; George E. Templeton, university professor, Department of Plant Pathology, University of Arkansas, Fayetteville, 72701. Phytopathology 81:905-909. Accepted for publication 29 March 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-905.

Spore germination of Phoma proboscis in vitro and resulting disease development were evaluated over a range of spore concentrations and after incubation at nine dew periods at each of five temperatures. Reduced percent germination on water agar occurred at spore concentrations above 10⁷ spores ml^–1. Spore germination on agar was optimal at 24 C. High levels of disease occurred on plants that received 12 h or more of dew at all temperatures tested, except 32 C. Fresh weight reduction in shoots and roots correlated well with disease ratings. Disease was enhanced relative to constant temperature treatments when plants from dew period temperatures of 16 and 20 C were maintained at a postdew temperature of 24 C. The results of these studies suggest that P. proboscis has potential for use as a mycoherbicide.