Germination and Appressorium Formation by Venturia inaequalis During Infection of Apple Seedling Leaves. Mary L. Turner, Extension Assistant, Department of Botany and Plant Pathology, University of New Hampshire, Durham 03824. William E. MacHardy, Professor, and David M. Gadoury, Research Associate, Department of Botany and Plant Pathology, University of New Hampshire, Durham 03824. Plant Dis. 70:658-661. Accepted for publication 10 February 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-658.

The rate of germination and appressorium formation of both conidia and ascospores of Venturia inaequalis was directly proportional to temperatures from 5 to 20 C, but condia germinated and formed appressoria more quickly than ascospores. Multiple-regression equations were developed to describe the processes of germination and appressorium formation on the basis of time and temperature.

Keyword(s): apple scab, epidemiology.