Olive farmers in Mediterranean countries struggle with the olive fruit fly, which damages olives and reduces oil production. Researchers tested special fungi that naturally infect and kill insects to see if they could control this pest at the soil stage when fly pupae are developing underground. Several fungal species, especially Beauveria bassiana, were effective at reducing survival of emerged adult flies by about 40% compared to untreated flies. This offers a promising natural alternative to chemical pesticides that can harm olive oil quality and lose effectiveness over time.