Effectiveness of cow's milk against zucchini squash powdery mildew ( Sphaerotheca fuliginea) in greenhouse conditions

Abstract

Efficacy of fresh cow milk was tested in five greenhouse experiments against powdery mildew ( Sphaerotheca fuliginea) on zucchini squash ( Cucurbita pepo). Plants were sprayed with milk at 5, 10, 20, 30, 40, and 50%, either once or twice a week. Additional treatments were fungicides (fenarimol 0.1 ml/l or benomyl 0.1 g/l) applied once a week and water as a control treatment. Severity of the powdery mildew was visually evaluated on individual leaves at weekly intervals and scored as percentage of leaf area infected for infected leaves. A negative correlation was found between the infected leaf area per infected leaf and milk concentration sprayed on plants for the five experiments. High concentrations of milk were more effective than the conventional fungicides tested. This study demonstrated that milk is an effective alternative for the control of powdery mildew in organic agriculture.