Density of Potato Leafhopper (Homoptera: Cicadellidae) in Response to Soybean-Wheat Cropping Systems

Abstract

Effects of vegetational diversity upon abundance of potato leafhopper, Empoasca fabae (Harris), were examined in four agroecosystems. One of the four cropping systems was a soybean monoculture; the other three were relay intercropping systems that varied in the amount of wheat, Triticum aestivum L. (a nonhost plant), planted between soybean rows. Each employed the same planting density and dispersion of a potato leafhopper host plant, soybean, Glycine max (L.) Merrill. The cropping systems formed a gradient of vegetational diversity of host/nonhost plant density. Soybean and wheat were co-present in experimental plots early in the season; following the wheat harvest, all four cropping systems were soybean monocultures. Preceding the wheat harvest, potato leafhoppers were substantially and significantly more abundant in the monoculture than in any of the intercropping systems. Leafhopper densities were extremely low in all the intercropping systems. After the wheat harvest, differences between the monoculture and intercropping systems gradually decreased, and fewer collection dates showed significant differences. Females and males had similar population dynamics and differences among cropping systems. No significant differences in abundance were found among the intercropping systems. Results suggest that the use of host/nonhost intercropping systems would provide growers with an alternative management tactic against potato leafhoppers.