Collaboratrices et collaborateurs

One of the challenges facing conventional fruit growing is to reduce the negative impact of plant protection products, while limiting economic losses. The aim of the Swiss project ArboPhytoRed is to run new strategies for reducing the use of synthetic plant protection products with particular risk potential by at least 30%, while limiting financial losses to less than 10%. On-farm trials have been set up in collaboration with fruit growers in Valais (Switzerland) to assess the effectiveness and feasibility of alternative plant protection strategies. In 126 apple, pear and apricot orchards, pests and diseases were monitored in reference plots and in alternatively treated plots. The results of the 3-year study showed that the use of alternative products can pose agronomic problems when pests and diseases pressure was heavy (particularly with scab and aphids). Besides, the use of alternative products required greater precision from the growers in terms of timing and techniques of application. The economic evaluation carried out in 2021 in apple orchards revealed a large reduction of the packout (part of 1st class fruits) and a slight increase in production costs resulting in a 56%-lower financial outcome for alternative strategies. On the contrary, the strategies implemented in the alternatively treated plots have led to a reduction of more than 46% in the number of phytosanitary interventions and of 56% in the quantity of synthetic active compound applied (all fruit species together). Additionally, the risk potential for living organisms in surface water was reduced by 42% for alternative strategies. Thus, the environmental performance of alternative plant protection strategies has largely been achieved, but at the expense of agronomic and economic performances. Therefore, alternative strategies need to be adapted in order to rebalance the various performances.