Evaluation of trichoderma strains as biocontrol of fusarium oxysporum f.sp lycopersici in tomato

Abstract

Tomato (Solanum lycopersicum L.) is an important crop which provides people with essential nutrients e.g. potassium and phosphorus as well as anti-oxidants important in fighting cancers. Its production is threatened by the wilts caused by a fungus called Fusarium oxysporum f.sp Lycopersici which can cause yield losses of 50- 100 %. The disease is mainly controlled by use of synthetic chemicals which can pose a threat to human health and the environment. This study evaluated the use of Trichoderma strains as potential biocontrol of the Fusarium oxysporum f.sp Lycopersici. In-vitro experiment was a dual culture experiment with six treatments arranged in a Completely Randomized Design. The results showed Trichoderma strains (T. harzianum, T. asperellum – CA, C9, NY) reduced mycelial growth of Fusarium significantly (p ≤ 0.05). The Trichoderma strains also showed a significantly high percentage inhibition of the pathogen (p ≤ 0.05). The in- vivo experiment of tomato variety Tengeru evaluating two factors (2 methods of application and 3 biocontrol spp) and was arranged in completely randomized block design with six treatment combinations and three blocks. The experiment showed that Trichoderma harzianum and Trichoderma asperellum CA significantly (p<0.05) reduced the effects of the pathogen when compared with the control and improved the growth parameters of the tomato plants as well as chlorophyll content. The Trichoderma strains did not influence chlorophyll florescence (p ≤ 0.05). Disease severity was significantly lower in Trichoderma inoculated treatments at (p<0.05) and lower in the control. Soil drenching proved to be a more effective method of application than seed treatment as shown in this study on many parameters. Trichoderma strains had significantly higher germination percentages (p ≤ 0.05). The Trichoderma asperellum strains (CA and C9) significantly increased vigor Appendix (p<0.05) and significantly reduced the disease incidence percentage (p<0.05). Trichoderma spp was effective in suppressing Fusarium oxysporum L.