Avocado plants are threatened by a fungal disease called root rot that damages roots and reduces fruit production. Researchers discovered that when avocado roots become diseased, the beneficial bacteria in the soil around the roots decrease significantly. They isolated a beneficial bacterium called Bacillus siamensis NB92 from healthy avocado soil that can fight against the disease-causing fungus by producing special compounds. When applied to diseased soil, this bacterium reduced the fungal pathogen and protected avocado stems from damage, offering a natural alternative to chemical treatments.