White Stuff on Orchids
Orchids are often grown for their colorful blooms. With thousands of species of orchids available to the home gardener, deciding which species to grow can be a difficult choice. Although orchids are generally healthy, they are susceptible to a disease known as powdery mildew. This disease is characterized by the growth of a white, powdery fungus that develops on affected plants. Does this Spark an idea?
Other People Are Reading
-
Identification
-
Powdery mildew is a foliage disease caused by fungi. This fungi affects almost all species of ornamental plants. There are many types of powdery mildew fungi, and they usually affect different plants. However, powdery mildew symptoms are similar in most plants. Powdery mildew fungi thrive in humid climates but do not need water to reproduce. Moderately warm weather and high humidity are favorable for the development of this disease. Powdery mildew affects orchids growing in shaded areas, as this promotes humidity. Planting orchids too closely together also can lead to powdery mildew.
Types
-
Powdery mildew affects most ornamental plants, flowers, trees and shrubs. Orchids, roses, lilac, ash, phlox, dahlias, chrysanthemums, begonias, zinnias and snapdragons are all commonly affected by powdery mildew. Woody ornamentals such as dogwood, cherry, crab apples, honeysuckle, English oaks, sycamore and willow are also attacked by powdery mildew fungi.
-
Effects
-
Powdery mildew is characterized by white fungal growth covering host plants. This fungus resembles talcum powder and is often found on the lower leaves of the plant first. Young, succulent plant tissue is attacked by powdery mildew more often than older leaves. Leaf twisting, leaf curling and yellowing of foliage are also noticeable on orchids with powdery mildew. Powdery mildew is seldom fatal, but it can become severe and unsightly.
Control
-
Cultural controls often reduce the severity of powdery mildew in orchids and other plants. Purchasing powdery mildew-resistant orchids is one way to prevent the disease. Visit a reputable nursery or home gardening center to purchase your plants. Keep your orchids in good health and remove and destroy infected leaves. Plant your orchids in an area that will receive a minimum of six hours of sunlight each day, as this will reduce the likelihood of powdery mildew development. Avoid overhead watering and provide your orchids with water early in the morning. This allows time for the plant to dry entirely before nightfall and reduces powdery mildew attacks.
-
