Organic fruit production in humid climates of Europe: Bottlenecks and new approaches in disease and pest control

Summary

The organic market has grown exponentially in Europe during the last ten years. However, the organic fruit industry has shown the lowest growth rates (1-5% market share) compared to other commodities. One major reason is the high production risk due to high disease and pest pressure in humid climates. Key pests and diseases in apple and pear include scab, sooty blotch, and fire blight as well as rosy apple aphid, pear sucker, and codling moth. In cherry, damages due to brown rot (Monilinia) and the cherry fruit fly make organic production almost unfeasible. In an ideal organic system, all possible measures that lead to improved stability of the system must be implemented. In fruit production, such measures include (i) use of resistant varieties (scab), (ii) active promotion of predators (rosy apple aphid), (iii) sanitation (cherry monilinia), (iv) microclimate management (planting density, covering trees), and (v) strengthening the plant self-defence system (e.g. building up of soil fertility, bio-dynamic preparations). At present, most organic orchards have been designed for conventional production and, therefore, lack most stabilising components. In consequence, organic fruit production still depends largely on direct pest and disease control methods. These include traditional pesticides such as copper, sulphur, and lime sulphur, pyrethrin, oil and soap preparations. More recently, new pest control compounds and techniques have been developed including neem products, granulosis virus, and mating disruption. New tools for disease control are less spectacular and focus on the replacement of copper (e.g. with clay powders and resistance inducers). The introduction of new equipment, materials, and Decision Support Systems (DSS) will further improve yield stability. However, other limiting factors such as weed competition, crop load regulation, and conventional market demands need innovative solutions.