Do differences between organic crop protection strategies influence generalist predator communities and predation of codling moth eggs in apple orchards?

Crop protection strategies used in organic agriculture can vary considerably, which may affect natural enemy communities and pest control. Twenty organic apple (Malus domestica) orchards in south-eastern France were categorised according to their protection strategy as Alt’Carpo netting (A), biodynamic (B), or classic organic (C). Pesticide use, abundance of main predators and predation of codling moth, Cydia pomonella (CM), during the first (May), second (July) and third (August) CM generation in 2012, were analysed. The different protection strategies resulted in significant differences in the pesticide use, depending on the dates, with generally higher reliance on fungicide and insecticide under C. In August, abundance of total predators under A was not significantly different from that in B and C, but was significantly higher under B than under C. Earwig (Forficula spp.) abundance in July and August was significantly higher under B than in A and C. In August, abundance of Cheiracanthiidae spiders under B was not significantly different from that under A and C, but it was significantly higher under A than under C. Total predation rate of sentinel eggs increased from 14.1% to 45% from May to August. In May, predation rate was significantly higher under A than under B and C, and in August it was higher under B than under A and C. In general, correlation between abundance of predators and predation rate was significantly positive according to the CM generation. The findings suggested that the most efficient predators were different for each CM generation in the orchards.