Impact of crop protection strategies on natural enemies in organic apple production

Organic farming is mainly viewed as a homogeneous production system. Organic farming is also commonly thought to favor natural enemies of pests for crop protection. However, organic farming involves very different management practices and, in turn, various protection strategies. There is little knowledge on the influence of protection strategies on natural enemies in organic agriculture. Here, we analyzed crop protection strategies of 24 organic apple farmers in Southeast France. We also analyzed natural enemy communities in 12 apple orchards. We measured the impact of strategies on natural enemies using the International Organization for Biological and Integrated Control (IOBC) toxicity index. We identified four protection strategies: (1) the ecologically intensive strategy which promotes natural enemies by habitat management, (2) the substitution strategy mainly based on the use of pesticides, (3) the technologically intensive strategy which uses innovative technological methods such as exclusion nets and the integrated strategy which mobilizes a wide range of different practices. The IOBC toxicity index was 78.8 +/- 23.0 for the substitution strategy, 60.75 +/- 15.0 for the integrated strategy, 37.4 +/- 11.9 for the ecological strategy, and 31.25 +/- 1.7 for the technological strategy. We also found that the four strategies have different natural enemy communities such as the higher abundance of Forficula pubescens in the ecological strategy.