There are white spots in the soil and on the roots of my moth orchid? What are they and how do I get rid of them?
The most likely cause of these white spots is fungus called snow mold. Your orchid is getting and retaining too much water. Changing the growing medium out of a moss based soil to a bark, perlite & charcoal soil will help airflow in and around the plant roots. Also changing the pot to a plastic pot with holes on the bottom as well as slits in the sides will maximize drainage & airflow. A liquid fungicide can be used on the roots before the plant is re-potted up with the new soil. Orchids like humid atmospheres but don’t like to have their soil kept wet so misting the air around the plant occasionally during our dry overheated winter would be beneficial. It is important to get this mold under control: you don’t want it to spread to cover the roots as orchid roots are used for moisture capture and photosynthesis.
There is also a small chance that these white spots may be mealybugs so a thorough inspection of the entire plant is needed to see if there is evidence of infection on the crevices of the leaves. If so, a good washing with a shower head and the use of an insecticidal soap would be beneficial.