Are lower pesticide doses better? An evolutionary perspective on integrated pest management

Pest management approaches, based on Integrated Pest Management (IPM), suggest that pesticide use could be reduced if dose recommendations move from a toxicological perspective (how much is needed to kill pests) to an ecological perspective (how much is needed to guarantee crop yield while minimizing environmental damage). However, the success of pesticides in maintaining crop yield security may be compromised by the evolution of resistance, which can be accelerated by reducing pesticide doses. To explore these relationships, we developed a mathematical model to evaluate the potential effect of pesticide dosing and pesticide-induced stress on mutation rates leading to major single gene resistance, or the accumulation of the multiple mutations leading to multi-factorial resistance. One of the main focuses was to determine the relative importance of resistance development generated before (i.e., pre-resistance) and after (i.e., post-resistance) pesticide exposure, tracking the proliferation of resistance under distinct scenarios of pesticide dosing. Our findings suggest that the relative importance of post-resistance increases under low pesticide doses and is particularly significant for the accumulation of resistance factors after pesticides are introduced. On the other hand, our model shows that lowering pesticide doses when used in conjunction with other control measures, can reduce the impact of post-resistance development. High pesticide doses may also hasten resistance if mutation rates increasingly scale with pesticide doses. This is due to the faster accumulation of resistance factors during pesticide administration. Under these circumstances, both ecological (i.e., reducing pesticide doses, minimizing biodiversity damage) and evolutionary (i.e., preventing resistance evolution) perspectives to the IPM framework are reconciled by lowering pesticide doses. Our results demonstrate the importance of taking evolution into account to evaluate management consequences, highlighting the urgent need to integrate the evolutionary perspective into pest management models to promote sustainability.