A NEW TOMATO FOLIAGE DISEASE IN ISRAEL CAUSED BYSTEMPHYLIUM BOTRYOSUM

Abstract

A serious leafspot and foliage blight disease of recent occurrence in tomato fields in Israel has been described, and the causal agent identified as Stemphylium botryosum Wallr. Most isolates of the pathogen produce the perfect stage Pleospora herbarum (Fr.) Rab. on nutrient media, but not in nature, either on living or dead plant tissue. The fungus is a highly virulent and very specialized pathogen capable of attacking only tomato foliage. This seems to be the first report of S. botryosum parasitic on tomatoes under normal field conditions. The pathogen is considered as a separate forma specialis and designated S. botryosum f. sp. lycopersici.