Wildflower plantings for conservation biological control: Floral resources support natural enemies and their control of pests in adjacent crop fields

Manipulation of the environment around crop fields to enhance biological control through establishing flowering plants has been shown to increase natural enemy populations in these areas. However, much less is known about the effect of these plantings on the biological control of pests within adjacent crop fields. We established habitat of native, perennial wildflowers in areas adjacent to blueberry fields, and recorded a higher abundance of natural enemies in the crop fields adjacent to wildflower plantings than in fields adjacent to control field perimeters.

Generalist predators, such as spiders, hoverflies, and lady beetles were among the dominant groups of natural enemies observed in blueberry fields. We used corn earworm eggs, Helicoverpa zea (Lepidoptera: Noctuidae), as sentinel prey and compared the number of damaged and missing eggs after one week in fields adjacent to flower plantings or control perimeters to calculate the biological control services index (BSI). We found significantly higher BSI values, and hence higher biological control of corn earworm eggs in fields adjacent to the wildflower plantings than in the control fields.

Our results indicate that wildflower plantings support natural enemy populations in agricultural landscapes, and the implementation of these plantings may be used to enhance biological control in adjacent crop fields.