Controlling Powdery Mildew in Euonymus with Polymer Coatings and Bicarbonate Solutions

Abstract

Powdery mildew in euonymus (Euonymus japonica Thunh.) plants, caused by Oidium euonymi-japonica (Arcang.) Sacc., was controlled by applying various polymer coatings or an aqueous solution of sodium or potassium bicarbonate plus horticultural Sun Spray (SS) Ultra Fine Oil 1% (v/v) to plant foliage. The combined treatment (bicarbonate + oil) was more effective than either of the two materials alone. The results indicate that sodium or potassium (but not ammonium) bicarbonate solutions mixed with SS seems to be a useful biocompatible fungicide for controlling powdery mildew in euonymus plants. Some of the polymer coatings effectively reduced disease levels when applied immediately after the symptoms first appeared.