There were tested water extracts from Syringa vulgaris and Pyrethrum parthenium. They did not prove signincant differences ofdecrease of the air attack ofColorado potato beetle (Leptinotarsa decemlineata), the activity ofeggs -laying and the occurrence oflarvae in comparison to the control. Interesting trends oflower-eggs lying and a lower larvae occurrence were discovered. The liquid spray against the late blight (Phytophthora infestans) did not signincantly decrease neither occurrence oflate blight or the yield.
The production of the bio-potatoes is only 0,2% of all potatoes production in the Czech Republic. The aim of this experiment was to try alternative methods of regulation of Colorado potato beetle and late blight (the biggest harmful! organisms ofpotatoes).
For biological agriculture could be also suitable water extracts. These are possible to use as protection of potatoes against unfavorable factors (Colorado potate beetle and late blight) and increase yield and quality ofproduction
