Investigations were carried out to study the effect of soil temperature, moisture, nutritional factors and organic amendments on wilt incidence due to Fusarium oxysporum f. sp. cumini (FOC) in cumin and survival of F. oxysporum f. sp. cumini under greenhouse/controlled conditions. Soil temperature and moisture significantly (p<0.05) influenced wilt development in cumin. Maximum wilt incidence was recorded at 25°C, while it was minimum at 35°C. Maximum population of FOC was recorded at 25°C followed by 20 and 30°C. The recovery of the pathogen was comparatively less at 35°C. Wilt incidence and population of pathogen were the highest at 40% followed by 60% moisture holding capacity. F. oxysporum f. sp. cumini was influenced by nutrients and organic amendments. The lowest wilt incidence and pathogen population were recorded in neem cake + NPK + ZnSO4 treatment. The treatment vermicompost + NPK + ZnSO4 also significantly (p<0.05) reduced the disease and FOC population in soil. The wilt incidence and Fusarium population were also reduced in response to addition of ZnSO4 alone or in combination with NPK. With the increase in mycelial inocula of the pathogen from 5 to 10 g kg-1 soil, the wilt incidence increased irrespective of soil variables and treatments. The Fusarium population was higher at 30 days after application (DAA) as compared to 60 and 90 DAA.
Keywords: Fusarium oxysporum f. sp. cumini, temperature, neem cake.