[The effect of polyphagous predators on the population development of the cereal aphid Rhopalosiphum padi [Sweden]]

afidos agentes nocivos animal animal nuisible animales animales nocivos animals aphide aphids arthropode arthropods barley cebada cereales cereals crops cultivos cultivos de grano depredadores economic plants escandinavia europa europe facteur nuisible grain crops hemiptera homoptera human population injurious factors insecte insecte nuisible insectos insects invertebrados invertebrates noxious animals organisme nuisible orge pest insects pests plagas plantas plante plante de culture plants population population change population humaine predators rhopalosiphum scandinavia scandinavie suecia sweden