If it’s powdery mildew, an antifungal spray and improving airflow may help
What’s the problem?
My kalanchoe plant’s leaves have developed a strange white, powdery coating, and I’m worried it may spread.
Diagnosis
This sounds like powdery mildew, a common fungal disease. It thrives in warm, humid environments with poor airflow. Powdery mildew doesn’t usually kill a plant outright, but it weakens growth, damages leaves and can spread quickly to nearby plants.