Impact of flower strip establishment in apple orchards on natural enemy populations

Abstract: Composite flower strips were established in 2006 in three commercial apple orchards in Quebec. Strips were composed of the Canadian goldenrod (Solidago canadensis) and the common yarrow (Achillea millefolium), two native plants known to attract beneficial organisms. The aim of the project was to reduce pesticide application treatments directed against orchard pests, more specifically the European red mite (Panonychus ulmi), the two-spotted spider mite (Tetranychus urticae), the green apple aphid (Aphis pomi), the European apple sawfly (Hoplocampa testudinea), the tarnished plant bug (Lygus lineolaris) and the white apple leafhopper (Typhlocyba pomaria). In the present trial, populations of potential natural enemies of these pests were monitored in 2008, using sticky white traps, in both control and managed areas. The most common predator species were Coccinellidae, Syrphidae, Neuroptera (Chrysopidae and Hemerobiidae) and Aranea. Results varied according to the species of natural enemy, the treatment (control versus floral strip) and the distance to the flower strip.