Potential of basic substances in plant protection to reduce Podosphaera pannosa in cut roses

Abstract

Alternative strategies in plant protection are required due to political and environmental conditions. Basic substances can potentially benefit for modern plant protection in conventional and organic horticulture. In the case of plant protection in ornamentals, little is known about the effect of basic substances within the canopy to reduce foliar diseases. Podosphaera pannosa is one of the most severe diseases in the production of cut roses. In this study, different cultivars of cut roses were sprayed weekly with an extract of Equisetum arvense (4 g dried plant material/L), an aqueous solution of hydrogen peroxide (10 g/L) and a commercial plant protection product containing potassium hydrogen carbonate (VitiSan, Biofa GmbH, Münsingen, Germany) during two experimental trials. As a result, the symptoms of infected leaf area could be reduced significantly as the experiments progressed. Furthermore, no negative effects such as a reduction of plant growth or the number of marketable flowers were observed. The results indicate that the foliar application of the basic substances hydrogen peroxide and E. arvense-extract has the potential to reduce the use of synthetic plant protection products in conventional and organic horticulture.