White Mold at the Base of an Orchid

Mealybugs

• Mealybugs are a common orchid pest that leave white, fuzzy, mold-like material all over the base of the orchid, leaves and blossoms. The mealybugs themselves may only be less than a third of an inch long, making it easier to spot the fluffy material left behind than the actual bugs themselves.

Mold

• White mold can infest the base of an orchid plant if it is overwatered or too moist. This mold is sometimes called snow mold and grows in the potting medium when it begins to break down. The mold doesn't grow on the orchid itself, but it can suffocate the roots and lead to the death of the orchid. Fungicide can be used to treat mold.

Treatment

• Wiping a cotton ball soaked in rubbing alcohol over the stem, exposed roots and leaves of the plant can kill mealybugs, while larger mealybugs can be pulled off of the plant by hand. Insecticidal soap is also a good treatment method, but multiple treatments will be needed until the problem is resolved. Other options include neem oil and mineral oil, used in the same manner as rubbing alcohol.

Prevention

• When bringing a new orchid into your home, inspect it carefully for signs of a moldy white substance before placing it near other household plants or orchids. Preventative insecticidal soap treatments can be given anyway. To prevent mold growth on orchids, ensure that orchids are not always moist.