Antifungal effect of a local Bacillus subtilis, isolate TM07, on Fusarium oxysporum f.sp. Lycopersici in Morogoro, Tanzania

Fusarium oxyporum f.sp. lycopersici causes tomato wilt, a severe disease that leads to extensive yield and quality loss of tomatoes in Tanzania. Management of Fusarium infection is particularly challenging given the health and environmental concerns over continued use of chemical pesticides on horticultural food crops. However, there is an increasing focus towards the use of biocontrol agents to combat phytopathogens worldwide. In this study, bacterial isolates from tomato rhizosphere were screened for their antagonistic activity in vitro on F. oxysporum. Based on its superior effectiveness, one isolate, designated TM07, was selected and characterized as Bacillus subtilis by morphological, biochemical and molecular procedures. On potato dextrose agar (PDA) the isolate showed an appreciable degree of radial growth inhibition (RGI) of 40.5% of the Fusarium, compared to control (55.9%). Further investigations are recommended to elucidate on the mechanism behind the inhibitory effect of isolate TM07. In vivo studies are also recommended to assess the possibility of applying the B. subtilis, isolate TM07, as a local biocontrol agent of Fusarium wilt of tomato and other susceptible crops.