Abstract
Pesticides are the main solution against crop pests worldwide, despite their unsustainable nature due to the environmental and human damage they cause. This is particularly salient in less developed countries, as is the case for smallholder farmers in the tropical Andes. The objective of this thesis is to increase the sustainability of pest management practices in the tropical Andes. To do so, we use key concepts of sustainability science (the multi-scale approach, transdisciplinary, and participatory research) to understand the socio-ecological dynamics at work in the agroecosystem. At each spatial scale, potential major driving forces and obstacles were co-identified by farmers and scientists and analyzed using relevant disciplines. At the plot scale, the temporal dynamics of the pests were modeled, thus guiding the timing of application of control methods. At the landscape scale, the impact of the interaction between the presence of non-crop areas and pesticide application on pollinators and pests was examined, highlighting the negative effect of pesticides on pollinators. At the same scale, farmers' perception of the Andean landscapes and the services they offer was assessed, allowing the identification of potential nature-based solutions. At the tropical Andean scale, through surveys of pesticide retailers, farmers have highlighted the pervasiveness of erroneous recommendations regarding the use of pesticides. Finally, at the scale of the tropics, we analyzed insecticide literature produced in this region in order to orient it towards greater sustainability. These results distributed across the different scales were then combined to draw a causal chain at work in the socio-ecosystem, allowing us to identify pesticide dealers as a major cause and driving force requiring change in order to achieve sustainable crop protection. Solutions are offered by exploring conflict of interest as a cross-cutting theme responsible for the unsustainable nature of crop protection in the tropical Andes.