Disease management in both traditional and controlled environment agriculture is as old and complex as the practice itself. In controlled environments disease can spread quickly and lead to significant losses if not properly managed. This first installment of Hort Americas' mastery series discusses how to recognize, control and prevent powdery mildew in leafy greens.
Powdery mildew is a plant disease recognized by infection from different fungi species: Golovinomyces cichoracearum, Erysiphe, Microsphaera, Leveillula, Sphaerotheca, Uncinula, Phyllactinia and Podosphaera. Usually infections are crop specific. In most cases of powdery mildew in leafy greens, such as lettuce, the culprit is Golovinomyces.
Powdery mildew is a very common disease and the symptoms in leafy greens and can be recognized by gray to white powdery spots in plant leaves. Usually older leaves will be the first ones to show symptoms leading to chlorosis and deformities.
Powdery mildew can be triggered by warm temperatures, high humidity, poor airflow and low light levels and can be problematic in zones with dense canopies. When indoor farming is not properly managed, the environmental conditions can promote powdery mildew.
By applying good cultural practices, powdery mildew can be avoided or easy to control.