Organic management of cherry orchards favours most natural enemies and some phytophages

Abstract Arthropods were sampled in organic and conventional cherry orchards over two growing seasons using pitfall traps, yellow sticky traps, and branch shaking. The data obtained from both production systems were compared using linear mixed effects models and principal response curves (PRCs). The diversity of families and the total abundance of arthropods captured by the three sampling methods were significantly greater in the organic orchards. Phytophagous and predatory arthropods in cherry tree canopies, soil-dwelling predators and parasitoids captured in yellow sticky traps were significantly more abundant in organic orchards. Although no significant differences in the total abundance of Coccinellidae between crop managements were recorded, species richness and abundance, excluding that of Stethorus pusillus (Herbst) (Coleoptera: Coccinellidae), were significantly greater in the organic plots. According to the PRC analyses, the taxa most favoured by organic management were the predatory families Anthocoridae, Lycosidae, Staphylinidae, Gnaphosidae, Philodromidae, Hybotidae, Nabidae, Carabidae and Thomisidae; the parasitoids belonging to Pteromalidae, Mymaridae, Braconidae, Bethylidae, Platygastridae and Aphelinidae; and the phytophagous Monosteira unicostata (Mulsant & Rey) (Hemiptera: Tingidae) (poplar lace bug) and aphids. The predatory coccinellid species most favoured by organic cropping were Adalia decempunctata (L.) (Coleoptera: Coccinellidae), Adalia bipunctata (L.) (Coleoptera: Coccinellidae) and Scymnus interruptus (Goeze) (Coleoptera: Coccinellidae). In contrast, some groups of arthropods were more abundant in conventionally managed orchards, among which spider mites and their predatory species S. pusillus (Herbst) stood out. Therefore, this study revealed a great benefit of organic cherry cultivation for most groups of predators and parasitoids although some phytophagous species were also favoured.