Effects of Spacing Between Rows on Soybean Arthropod Populations

(1) During summer 1976, population levels of various herbivores and all predators and parasitoids were monitored by three sampling methods (direct observation, sweepnet, vacuum net) on three different row-spacing plantings of `Williams' soybean with each planting treatment replicated three times. (2) The potato leafhopper Empoasca fabae (Harris) was most abundant in conventional row-spacing (96 cm) plots. Other herbivores were favoured in reduced row-spacing (high density) plots. (3) All predators and parasitoids which showed significant differences among treatments reached highest population levels in the high density plantings. Reasons for the observed patterns are discussed.