Effect of Mineral Nutrition and Salt Spray on Cucumber Downy Mildew ().

It was previously shown that spraying with CaCl, MgCl, KCl, and KSO and high N and Mg concentrations in the irrigation water of potted cucumber plants reduced powdery mildew, while medium P and high K concentrations increased powdery mildew. In the present work, we tested the effect of irrigation with N, P, K, Ca, and Mg and spraying with salts on downy mildew () of cucumber (CDM). In potted plants, an increase in N concentration in the irrigation water resulted in a major increase in CDM severity, while an increase in K or Ca concentrations resulted in a gradual increase in CDM severity.

Nutrient Status of Cucumber Plants Affects Powdery Mildew ().

We examined the effects of applications of N, P, K, Mg, and Ca through an irrigation solution and spraying K, Ca, and Mg salts on cucumber powdery mildew (CPM, ) in potted plants and under commercial-like conditions. Spraying CaCl and MgCl, or KCl and KSO, decreased CPM. There were significant negative correlations between the anion-related molar concentrations of the salts and disease severity.