How the epidemiology of disease-resistant and disease-tolerant varieties affects grower behaviour

Summary

This mathematical modelling study examines how the epidemiological properties of disease-resistant versus disease-tolerant crop varieties shape grower behaviour and long-term adoption patterns. By coupling epidemiological dynamics with game-theoretic decision-making, the authors demonstrate that tolerant varieties create misaligned incentives—benefiting individual adopters whilst leaving population-scale disease pressure unchanged—whereas resistant varieties generate positive externalities. The analysis reveals distinct equilibrium outcomes: tolerant crops can induce bistability, but resistant crops nearly always persist in mixed equilibria due to free-riding by unimproved-crop growers.

UK applicability

The model's predictions on incentive structures and adoption equilibria are applicable to UK cereal and horticultural systems facing endemic diseases, particularly where policy or extension services promote varietal choice. However, the findings are generic to the underlying epidemiology and game theory; field validation against actual UK grower behaviour and disease surveillance data would be necessary to guide deployment recommendations.

Key measures

Population-scale disease pressure; grower yields; variety adoption equilibria; bistability conditions; free-riding effects on resistant crop deployment

Outcomes reported

The study modelled how growers' decisions to adopt disease-resistant versus disease-tolerant crop varieties affect population-scale disease pressure, yields, and long-term equilibrium outcomes using coupled epidemiological and game-theoretic models. Key reported outcomes include conditions under which mixed variety equilibria persist, bistability between tolerant-crop and disease-free scenarios, and the tendency for resistant varieties to remain in mixed equilibrium due to free-riding behaviour.

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