Biological Control of <i>Tuta absoluta</i> Using Commercial Entomopathogenic Fungal Endophytes: Colonization Efficiency and Greenhouse Efficacy

The tomato leafminer, <i>Tuta absoluta</i> (Meyrick) (Lepidoptera: Gelechiidae), is one of the most destructive pests of tomato crops worldwide. Its high reproductive potential and increasing resistance to conventional insecticides have made the development of sustainable management strategies essential. Biological control using entomopathogenic fungi (EPF), particularly when established as endophytes, has emerged as a promising approach. This study investigated the endophytic colonization capacity and greenhouse performance of three commercially available EPF formulations: <i>Beauveria bassiana</i> (Velifer^®), <i>Lecanicillium lecanii</i> (Lecan^®), and a <i>Beauveria bassiana</i>–<i>Metarhizium anisopliae</i> mixture (Metab^®), for the suppression of <i>T. absoluta</i> in tomato. Our experiment was conducted under commercial greenhouse conditions using soil drench applications at manufacturer-recommended doses. Endophytic colonization was assessed through surface-sterilized leaf assays, while pest suppression was evaluated via weekly measurements of larval mine length, infestation incidence, and survival dynamics. <i>B. bassiana</i> (Velifer^®) exhibited the highest endophytic colonization frequency and consistently reduced mine length and infestation levels compared with untreated plants. Survival analysis using Cox proportional hazards revealed significant reductions in infestation risk for Velifer^® (hazard ratio, HR = 0.420), Metab^® (HR = 0.480), and Lecan^® (HR = 0.599), relative to the negative control, whereas the chemical positive control provided the strongest overall suppression (HR = 0.287). Our findings demonstrate that commercial EPF formulations can significantly reduce <i>T. absoluta</i> infestation under greenhouse conditions and represent a valuable component of integrated pest management programs.