Increasing the proportion of flower strips promotes natural enemies to enhance aphid biocontrol and wheat yields

Abstract

Abstract Sowing flower strips adjacent to cropsis an effective practice for promoting natural enemies, enhancing biological pest control servicesand conserving biodiversity. However, few studies have considered the relationships of the proportion of flower strips with pest control servicesand crop yield. We conducted a three-year field experiment (including a control: 0% and three treatments: 5%, 10% and 15%) to determine the biocontrol service potential of sowing strips of Cnidium monnieri (L.) Cuss flowers adjacent to wheat and to reveal the relationships of the proportion of flower strips with pests, natural enemies, biological pest control services and wheat yield. Compared with the control (0%), flower strips promoted suppression of wheat aphid abundance by ladybugs and parasitoids. With an increasing proportion of flower strips, the predatory ladybug abundance and parasitism rates increased, while aphid abundance decreased. The relative biocontrol services index (RBSI) in the control (0%) was significantly lower than those in the treatments (5%, 10% and 15%). The wheat yield in the control (0%) was significantly lower than those in the treatments (5%, 10% and 15%). With an increasing proportion of flower strips, the RBSI and yield increased. In conclusion, sowing strips of C. monnieri flowers adjacent to wheat is a promising measure for providing considerable biocontrol services and increasing wheat yields. Specifically, natural enemies, biocontrol service potential and wheat yield were enhanced with an increasing proportion of flower strips. A 10% or 15% installment of flower strips is suggested to provide substantial biocontrol services and sustain wheat yields.