In 2018, at the Laboratory Field of the Biotechnical Faculty, we studied the non-targeted effect of extracts of seven selected invasive alien plant species on pollinators and natural enemies. The experiment was based on the crop of buckwheat (Fagopyrum esculentum MOENCH) and phacelia (Phacelia tanacetifolia BENTH.). It measured 780 square meters and was divided into 4 blocks. Within the blocks, we dealt randomly with 10 treatments: 1) Bohemian knotweed (Fallopia x bohemica), 2) Reynoutria japonica (Fallopia japonica), 3) leaves of Canada Goldenrod (Solidago canadensis), 4) Giant Goldenrod (Solidago gigantea), 5) Tree of heaven (Ailanthus altissima), 6) Indigo bush (Amorpha fructicosa), 7) Staghorn cumac (Rhus typhina), 8) Canada Goldenrod flowers (Solidago canadensis), 9) positive control (Karate Zeon 5 CS insecticide) and 10) negative control (non-sprayed). During the flowering of buckwheat and phacelia, we applied sprays prepared from extracts of invasive alien plant species with a manual sprayer to the crop. By counting the bees, bumblebees, Coccinellidae, lacewings and predators from the family Pentatomidae before and after spraying, we tested two hypotheses. In both crops, fewer pollinators and natural enemies would appear after spraying with the extracts of selected invasive alien plant species than in non-sprayed crops (negative control). We also confirmed the hypothesis that fewer pollinators and beneficial organisms would appear on both crops sprayed with the chemical insecticide (positive control) than when buckwheat and phacelia were sprayed with extracts of invasive alien plant species.
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