Plant-Based and Biocontrol Alternative Approaches for Managing Fusarium Wilt of Tomato (Solanum lycopersicum L.) in Burkina Faso

Abstract

Vascular Fusarium wilt, caused by Fusarium sp., is a major constraint to tomato production in Burkina Faso. This study aimed to evaluate the pathogenic variability of local Fusarium strains and the efficacy of plant-based treatments against the pathogen. Eight Fusarium strains were inoculated on the Cobra F1 variety via stem injection and foliar application. The in vitro antifungal activity of aqueous extracts (25–75%) and oils (100-200 ppm) from three local species (Ocimum gratissimum L., Azadirachta indica A. Juss., and Jatropha curcas L.), as well as Trichoderma sp. suspensions (5–15%), was assessed on PDA medium, with Mancozeb (5 g/L) as a positive control. The effectiveness of these treatments on seed contamination and germination was also tested using the blotter paper method. Results showed high virulence of the T2F strain on Cobra F1, with a severity index of 9.37 (75%) 40 days after inoculation. Aqueous extracts of O. gratissimum at 50% and 75% concentrations exhibited strong mycelial inhibition (88.89% and 94.84%), statistically comparable to Mancozeb (>96%). Oils of A. indica (200 ppm) and J. curcas (200 ppm) also demonstrated notable activity (84.64% and 74.69%). Trichoderma sp. conidial suspension at 15% reduced mycelial growth by 66.92% and limited seed contamination to 4%, a level close to that achieved with Mancozeb (3.55%). These results indicate that O. gratissimum extracts and Trichoderma sp. have promising potential to be integrated into sustainable management strategies for tomato vascular Fusarium wilt, as alternatives or complements to synthetic fungicides, thereby highlighting their practical relevance for local farmers and sustainable agricultural development in Burkina Faso.