Description: White or powdery growth on Plumeria roots is typically caused by powdery mildew, a fungal infection. Causes: Powdery mildew can infect the roots and cause the characteristic white growth. Solutions: Apply fungicides: Use appropriate fungicides to treat powdery mildew, following the product instructions carefully. Improve air circulation: Ensure proper ventilation around the roots to reduce humidity and fungal growth. Monitor and care: Regularly check the roots for signs of powdery growth and adjust care accordingly.