Microbial biocontrol of Fusarium oxysporum in tomato using Papiliotrema terrestris, Bacillus amyloliquefaciens and Trichoderma harzianum under greenhouse conditions

Abstract

Fusarium oxysporum is a persistent soil-borne pathogen that causes severe vascular wilt in tomato and remains difficult to manage under intensive greenhouse production. This study evaluated the individual and combined performance of three microbial antagonists, Papiliotrema terrestris PT22AV, Bacillus amyloliquefaciens BO7, and Trichoderma harzianum T22, against the aggressive isolate FO23 under controlled greenhouse conditions. Tomato seedlings of the susceptible cultivar San Marzano Nano were grown in pathogen-infested substrate and treated with microbial agents individually or as a consortium. Plant response was assessed through symptom expression, chlorosis, plant height, leaf area, vigor, and overall disease suppression. Among the single agents, PT22AV showed the strongest performance, combining visible disease suppression with a clear biostimulant effect. BO7 also reduced pathogen damage and improved plant development, whereas T22 provided only modest protection under the tested conditions. The microbial consortium composed of PT22AV, BO7, and T22 produced the best overall plant response, with improved vigor, greener foliage, and reduced symptom severity compared with the pathogen-only treatment. The observed differences among microbial treatments indicate that biological control performance depends not only on pathogen suppression but also on the capacity of the antagonist to improve plant physiological status. The integration of complementary microorganisms within a consortium may therefore represent a promising strategy for sustainable greenhouse tomato production under high disease pressure.