Better outcomes for pest pressure, insecticide use, and yield in less intensive agricultural landscapes

Abstract

Increasing crop field sizes and decreasing seminatural area is believed to lead to increased pest pressure and insecticide use due to earlier and frequent pest immigration and fewer natural enemies. However, after decades of research on how landscape simplification affects pest pressure in crops, there is conflicting evidence. We show that smaller fields surrounded by landscapes with 20 to 30% seminatural area had delayed and reduced pest immigration and spraying while producing the highest yields. These findings reveal a previously untested link sequence starting from agricultural intensification through pest immigration and dynamics, to insecticide use and yield. Moreover, fine temporal analyses provide unique understanding of how these effects change over time and potential explanation for the inconsistencies in the literature.Agricultural systems have been continuously intensified to meet rising demand for agricultural products. However, there are increasing concerns that larger, more connected crop fields and loss of seminatural areas exacerbate pest pressure, but findings to date have been inconclusive. Even less is known about whether increased pest pressure results in measurable effects for farmers, such as increased insecticide use and decreased crop yield. Using extensive spatiotemporal data sampled every 2 to 3 d throughout five growing seasons in 373 cotton fields, we show that pests immigrated earlier and were more likely to occur in larger cotton fields embedded in landscapes with little seminatural area (<10%). Earlier pest immigration resulted in earlier spraying that was further linked to more sprays per season. Importantly, crop yield was the lowest in these intensified landscapes. Our results demonstrate that both environmental conservation and production objectives can be achieved in conventional agriculture by decreasing field sizes and maintaining seminatural vegetation in the surrounding landscapes.The anonymized data and R code data have been deposited in Figshare (https://figshare.com/articles/dataset/AI_pests_insecticides_yield_csv/12062370, https://figshare.com/articles/journal_contribution/R_code_for_all_models/12072105, and https://figshare.com/articles/journal_contribution/R_code_for_all_Figures/12072108). All other study data are included in the article and/or SI Appendix.