PEACH APHID MANAGEMENT IN ORGANIC AND CONVENTIONAL ORCHARDS: HOW TO RECONNECT EFFICIENCY AND ECOLOGY?

Abstract

Considering the various negative side effects of intensive chemical pest control practices, a fundamental shift towards alternative approaches for crop protection is at stake in the agricultural sphere. The control of peach tree aphids requires regular and numerous treatments to achieve protection against direct damage and virus transmission. However, aphid populations are known to be affected by cultural practices and by natural enemies. These are more ecologically sound practices, but their efficiency is questioned. In 2007, we identified and evaluated the protection strategies used on 20 commercial fruit farms (8 organic and 12 conventional farms) in the south of France. We used different data sources: comprehensive interviews, peach orchard protection schedules and monitoring of aphids and beneficial arthropod populations at plot level. A clear distinction between conventional and organic farming appeared. Organic farmers adopted a more integrated management strategy combining alternative and cultural methods rather than only direct control methods. The organic strategy was less efficient than the conventional, which had significantly lower specific infestation indexes. However, the organic strategy promoted diversity and abundance of aphid natural enemies. Efficiency and diversity of these beneficial species appear to be in opposition or are incompatible. However, the redesign of crop protection, and more generally, of the orchard, with regard to the integration of all factors that influence the system, tends to reconnect efficiency and ecology.