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Ecology and Epidemiology

Multiplication of Pseudomonas syringae pv. glycinea on Soybean Primary Leaves Exposed to Aerosolized Inoculum. G. Surico, Researcher, Centro di Studio su le Tossine e i Parassiti Sistemici dei Vegetali del C.N.R., Instituto di Patologia Vegetale, Universíta degli Studi, Facolta di Agraria, 70126 Bari, Italy; B. W. Kennedy(2), and G. L. Ercolani(3). (2)(3)Visiting professor and professor, respectively, Istituto di Microbiologia Agraria e Tecnica, Universita degli Studi, Facolta di Agraria, 70126 Bari, Italy, (2)Permanent address: Department of Plant Pathology, University of Minnesota, St. Paul 55108. Phytopathology 71:532-536. Accepted for publication 29 October 1980. Copyright 1981 The American Phytopathological Society. DOI: 10.1094/Phyto-71-532.

Aerosol generated from a suspension containing 2 × 10⁸ colony-forming units (CFU) of Pseudomonas syringae pv. glycinea per milliliter was admitted into a stirred-settling chamber containing potted cultivar Acme soybean plants with unifoliolate leaves fully unfolded and one-half to two-thirds expanded. Epiphytic populations averaging 10³ and 10⁴ CFU · cm^–2 developed in 9 and 14 days, respectively, on leaves that were wetted gently with atomized water before inoculation and kept at 20 C without further wetting. Infection did not take place on these leaves. Bacterial blight symptoms developed consistently on leaves that were either wounded and wetted or water-soaked and wetted immediately before inoculation. Interposition of up to 48 hr between water-soaking and inoculation did not prevent infection if leaves were wetted again immediately before exposure to aerosol. Bacteria did not become established either upon or within untreated leaves.