Indicators to assess the environmental impact of protection practices in apple orchards
Abstract: Apple fruit production requires the application of numerous pesticides, mostly targeted against scab, codling moth and aphids. A Principal Component Analysis of the protection practices in 54 randomized apple orchards of a small production area near Avignon, in south-eastern France, produced 4 groups of growers relying on the protection strategy against Cydia pomonella: organic production, exclusive use of mating disruption (MD) against C. pomonella, intensive use of chemical insecticides (intensive), and a fourth group with both MD and chemicals (intermediate). The environmental impacts of these management strategies were assessed using two different indicators: i) the environmental impact quotient (EIQ) accumulating the impacts on farmers, consumers and non human biota, and ii) I-PHYARBO, a fuzzy expert system focusing on the environmental impact of pesticides. The outputs of these two indicators strongly differed from each other, the highest environmental impact being attributed to the organic orchards by EIQ while according to I-PHYARBO organic farming had the safest protection program. The three other protection systems did not differ strongly from each other whatever the indicator. This range discrepancy, which is conserved when considering only the beneficial organisms, is mainly due to the structure of the models. Unlike I-PHYARBO, EIQ assumes dose proportionality and a strict additivity of the effects of successive treatments, thus attributing high adverse effects to the organic programs that involve frequent applications of mineral fungicides. Attention has to be paid to the significance of these indicators, which may become useful tools to establish the consistency of pest-control strategies and recommendations.