Regulierung der Krautfäule(Phytophthora infestans) mit reduzierten Kupfer-Aufwandmengen im Kartoffelanbau

Summary in the original language of the document

Four field experiments were conducted in 2004 to analyse the efficacy of reduced rates of copper fungicides against Phytophthora infestans (3 x organic and 1 x conventional growing). Copper (Cu-hydroxide, Cu-oxychloride or Cu-octanoate) was sprayed in a weekly routine or according to the decision support system SIMPHYT with total dosages ranging from 0.57 kg/ha to 4.0 kg/ha. The results revealed in almost all treatments a significant reduction of late blight, except for the lowest rates (e.g. 4 x 0.14 kg/ha Cu as Cu-octanoate or 6 x 0.15 kg/ha Cu as Cu-hydroxide). There was a clear dose-response relation between increasing rates of copper and control of late blight in each experiment. Marketable yields varied from 132 dt/ha to 238 dt/ha in organic field trials depending on trial site and copper treatment. Generally, an effect of copper treatment and late blight on yield could be shown. Even a slight reduction of P. infestans increased yield by 10 % to 20 %. The influence of copper dosage on late blight was more obvious than influence of copper spraying on yield. A dropleg spraying system (copper application within the crop canopy) which was tested on one trial site did not improve blight control compared to conventional application.