Biotechnical Preparations in Protection of Cucumber against Downy Mildew

The effectiveness of the preparations PB 500 (extracted from cow dung) and PB 501 (silica fume – 92.8% SiO₂) in protection of cucumber against downy mildew was tested during the two-years experiment. PB 500 was used at 2% concentration and PB 501 at 1% concentration. The alternative fungicides recommended by the standard protection program were used as the reference agents. The effectiveness of the preparations PB 501 and PB 500 was lower than the conventional fungicides. It was observed that the infestation of protected plants is lower than the control plants, although not statistically significant. The results indicate a limited possibility of application of the tested formulations for cucumber protection against downy mildew in comparison to the chemical protection.