Building up, management and evaluation of orchard systems: a three-year experience in apple production

Abstract: Three apple orchard systems were planted in 2005 to assess agronomic and environmental effects of different pest management regimes: organic farming (OG), conventional supervised (SV) and low-input (LI) systems. Three apple cultivars presenting different susceptibility to scab were planted in each system: Ariane (Vf-resistant), Melrose (low-susceptibility) and Smoothee 2832T® (susceptible), creating nine «system x cultivar» situations. Decision rules were defined within the framework of each system, and their possible interactions were integrated. Starting from planting, the survey included pest and disease assessments, and agronomic and environmental parameters. The OG system was the slowest to produce commercial yield, whereas the SV one showed the highest performances. Although globally low, pest and disease fruit damage at harvest was the highest in the OG system. The treatment frequency index (TFI) was the highest in the SV system, and in Smoothee plots within each system. Two-fold more treatments were applied in any SV plot and in Smoothee OG compared to Melrose LI. The LI system presented the lowest TFI and the lowest environmental impact of pesticides calculated by the I-phyARBO fuzzy expert system. Apart from Smoothee, I-phyARBO in the OG system scored between LI and SV. From the first four years of the experiment, the importance of the cultivar in the management of the orchard diseases (and to some extent pests) is outlined whatever the system, with a high variation in the number of treatments. This experimental design proved to be a functional tool permitting the conception of decision rule patterns, and also to assess the agronomic, environmental and economical performances of the systems.