Are pests adapting to the push-pull system? Ecologically intensified farms in Kenya maintain successful pest control over time

Abstract

Ecological intensification utilizes biodiversity to maintain agricultural yields while reducing negative environmental impacts. While pest management is a common goal of ecological intensification, studies examining ecologically intensified pest management systems over longer time scales are rare. Using the push-pull system in Western Kenya, we examine whether pest abundance (for both insects and parasitic weeds) and yield vary with time since a given push-pull field was established. With a total of 1880 data points from 476 unique farmers and 24 cropping seasons, we found that pests declined with time since establishment in both push-pull and nearby control fields, while yield improved with time since establishment in push-pull fields. Although this study did not directly address mechanisms, it seems likely that pests in the push-pull system are not successfully adapting to overcome its pest management effects given the continued declines in pest abundance over time. Our data suggest that ecologically intensified agriculture may be resilient against pest adaptation over time, maintaining consistently high yields.