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

Abstract

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.

Factors driving growers’ selection and implementation of an apple crop protection strategy at the farm level

“…Based on these combinations, six types of strategies were identified on a rather small sample. This diversity of protection strategies within a common context was also observed by Marliac et al (2015), who identified four types of protection strategies within a sample of 24 organic apple growers in south-east France. However, given the number of interacting drivers involved, each farm studied appeared to be a unique case where these processes took specific values.…”

“…It also renders it possible to both aggregate and separate different types of products (Brunet et al, 2008). This indicator has already been used in several studies to compare different orchard production systems (Marliac et al, 2015;Simon et al, 2011;Laget et al, 2014).…”

Management diversity within organic production influences epigeal spider communities in apple orchards

“…the dominant species represents less than 80% of the trees). Some farmers under organic management chose to decrease the frequency of mowing to promote the abundance and diversity of natural enemies within orchards (Marliac et al, 2015). Since the ground cover density did not vary (natural grass species) and was very dense in all the orchards, we only characterised its mean height based on the measurements made at the two spider sampling dates.…”

“…Commercial organic apple orchards in the South-East of France are a highly sprayed crop with, on average, 25 pesticides applied each year (Sauphanor et al, 2009;Marliac et al, 2015). An additional advantage of orchards is their perennial and multi-strata status (soil surface, grass and trees) in which habitat management is thought to have greater effects (Landis et al, 2000;Simon et al, 2010).…”

Temporal activity of spiders and earwigs during winter in apple trees under a Mediterranean climate

“…Today, there is general agreement among the public and, growers that crop protection should rely less on the use of synthetic pesticides and more on agro-ecology principles (Jones et al, 2016;Marliac, Penvern, Barbier, Lescourret, & Capowiez, 2015). Among these principles, biological control through the promotion of natural enemies and with limited use of pesticides is of prime importance .…”