Pathogenicity, Host Range and Influence of Temperature, Humidity and pH Levels on the Growth of Fusarium oxysporum f.sp. lentis

Abstract

Background: Lentil is a vital nutritional source of protein in several parts of the world including India. The crop is susceptible to wilt which is a devastating soil-borne disease induced by the fungus Fusarium oxysporum f. sp. lentis. Insight of the potential threat Fusarium wilt can pose to lentils, a present study done on pathogenicity, host range and influence of temperature, humidity and pH levels on the growth of F. oxysporum f. sp. lentis.Methods: Ten isolates FOL-01 to FOL-10 of F. oxysporum f. sp. lentis (Fol) were isolated from wilted lentil plants that collected from different major lentil growing parts of Rajasthan. During 2017-18 a pathogenicity test was tested in pot house condition by seed and soil inoculation techniques for all isolates and epidomological factors evaluated in vitro conditions.Result: Results indicated that the Fol isolates represent a single race but differ in their aggressiveness on the susceptible cultivar L9-12. Pathogenicity test revealed clearly that Fol was associated with wilt symptoms and were pathogenic to lentil plants. A maximum percent disease incidence of 70.00 was showed by isolate FOL-02 in soil inoculation technique. In the morphological and cultural characterization, all the ten isolates showed various character in conidial frequency, colony color and growth pattern. Twenty plant species were tested to know the host range of Fol, out of these lentil, chickpea and pea show positive reaction with the pathogen. The influence of temperature, relative humidity and pH on the growth and sporulation of Fol was studied under in vitro conditions. Maximum mycelial growth and sporulation of the Fol were observed at 30°C, 6.0 pH and 60% relative humidity.