Beneficial soil fungi enhance tomato crop productivity and resistance to the leaf-mining pest Tuta absoluta in agronomic conditions

Research has shown that soil-borne beneficial microorganisms can enhance plant growth, productivity, and resistance against pests and pathogens and could thus serve as a sustainable alternative to agrochemicals. To date, however, the effect of soil-beneficial microbes under commercial crop production has been little assessed. We here investigated the effect of root inoculation with nine well-characterized bacterial and fungal strains and two consortia on tomato performance under intensive tomato crop management practices. We measured the impact of these root inoculations on plant growth, fruit quality, yield, and pest and pathogen incidence. While most microbial strains showed weak effects, we found that the fungal strains Trichoderma afroharzianum T22 and Funneliformis mosseae significantly increased marketable tomato yield. Moreover, we found that inoculation with most of the fungal strains led to a significant reduction in the incidence of the devastating leaf-mining pest Tuta absoluta, while this effect was not observed for bacterial inoculants. In addition, we found that microbial inoculations did not impact the incidence of introduced natural pest enemies, supporting their compatibility with well-established integrated pest management strategies in horticulture. In summary, the observed general positive effects of soil microbes on tomato yield and resistance reinforce the move toward broader adoption of microbial inoculants in future crop production, ultimately improving agricultural sustainability.