Terpinen-4-ol, a natural compound from tea tree oil, effectively kills gray mold fungus that spoils fruits and vegetables after harvest. The compound works by damaging fungal cell membranes, creating harmful reactive molecules inside fungal cells, and triggering the fungal cells’ self-destruction pathways. When tested on tomatoes and strawberries, terpinen-4-ol successfully reduced mold growth and disease spread, suggesting it could be a safe, eco-friendly alternative to chemical fungicides for protecting fresh produce.