First report of Alternaria phragmospora causing early blight disease of Lycopersicon esculentum in Egypt

Abstract

Tomato is one of the most common vegetable crops in the world. Many diseases would infect tomatoes during Tomato the growing season. In summer (August, 2018), from different fields (5 fields) severe brown spots appeared on the leaves, stems, and fruits of Lycopersicon esculentum variety Castle rock in the Abu El-Rish region, at Aswan city, Upper Egypt. The pathogen which isolated from different infected parts of the plant was identified as Alternaria phragmospora according to the morphological and molecular characterization using primers ITS1 and ITS4. The pathogenicity was tested by the re-inoculation of the healthy tomato plant from the same variety either by spore suspension (1.2x10⁶ conidia/ ml) spraying or direct mycelium inoculum on the plant surface. Virulent symptoms were observed in the inoculated plant. In the lab, moisture and high temperature increase the disease severity of infected plant while in the field, high temperature (40℃-47℃), excess watering of the plant and condensation of them in patches were recognized and these conditions increased the disease severity and spreading from plant to other. To our knowledge, this is the first detection of the pathogen, A. phragmospora which infected L. esculentum.