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Thursday, February 29th 2024

François Bareille will present “Strategic pesticide applications in organic-conventional mixed landscapes”, joint with Jean-Sauveur Ay (CESAER) and Vincent Martinet (PSAE).

Abstract:

Organic and conventional farmers face the same pests  but have heterogeneous tools and incentives to control them. This paper aims to theoretically and empirically characterise the strategic interactions to control pests that occur between these two types of farmers. Specifically, we develop a game theory model with two heterogeneous agents facing the same public bad to derive theoretically-consistent propositions related to the impacts of their specific characteristics on their respective pest control efforts. Our analyses indicate that organic farmers are likely to free-ride on the contributions of the conventional farmers when they manage a smaller part of the landscape, and vice versa. These strategic interactions are theoretically exacerbated when the exposure to pest abundance decreases, or when the heterogeneity of treatment efficacy or treatment expected payoffs between the two agents increase. Using exhaustive French data on insecticide purchases against the vector of a particular vine disease (Flavescence dorée), we provide empirical supports for all these propositions. Our preferred estimates indicate that organic farmers free-ride on conventional farmers' efforts until they represent about 6% of the landscape. Beyond this threshold, conventional farmers' efforts decrease and are partially substituted by those of organic farmers (by a factor 0.8 for 1). Conventional farmers eventually start to free-ride when organic farmers manage 72%  of the landscape. These results are robust to several sensitivity analyses. Finally, we empirically show that farmers' free riding behaviors almost disappear for high pest abundance, and that the heterogeneity of treatment efficacy and expected payoffs between farmers do affect their strategic interactions.