VIEW ARTICLE

Ecology and Epidemiology

Seasonal Variation in Populations of Pathogenic Pseudomonads on Soybean Leaves. T. W. Mew, IRRI, P. O. Box 933, Manila, The Philippines; B. W. Kennedy, professor, Department of Plant Pathology, University of Minnesota, St. Paul 55108. Phytopathology 72:103-105. Accepted for publication 11 May 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-103.

In each of two seasons, greater numbers of pathogens could be washed from symptomless soybean leaves approximately 6 wk after planting than earlier or later in the season. Numbers of both plant-pathogenic and nonpathogenic bacteria declined as leaves approached senescence. Early in the growing season, pathogenic races within the population tended to be specific to the cultivar from which they were isolated; late in the season, percentages of isolates pathogenic to a number of cultivars increased and cultivar-specific components of the total population decreased.