The effect of air and soil temperatures on fusarium oxysporum f sp lycopersici and verticillium dahliae wilt of spring and autumn tomatoes in morocco
Phytopathologische Zeitschrift 98(2): 97-107
The effect of soil and air temperatures on the percentage of tomato plants infected by F. oxysporum f. sp. lycopersici and by V. dahliae, the percentage of autumn and spring tomato plants showing symptoms, and on the vertical distribution of the 2 pathogens in the stems of wilted and of symptomless infected plants were studied. Both pathogens were present throughout the year. Soil temperatures during spring and autumn growing seasons were more favorable for Verticillium, and a greater percentage of plants were infected by Verticillium than by Fusarium. During the same periods, however, air temperatures were more favorable for the development of symptoms induced by Fusarium than by Verticillium. Stems of all Fusarium wilted plants were entirely colonized by the pathogen. Of Verticillium wilted plants, only 20-40% were entirely invaded by the fungus. In symptomless infected plants, Verticillium could be recovered from higher levels of the stem than Fusarium. Air temperatures during both growing seasons were favorable for vertical colonization of the plants by both fungi but for symptom production by Fusarium only.