Soybean aphid suppression and natural enemy movement in agricultural landscapes in Manitoba

Abstract

Landscape complexity and arthropod predators have been shown to play a major role in suppression of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae) in North America. I examined the impact of landscape complexity and patterns of predator movement between habitats on sentinel soybean aphid populations in 27 soybean fields in Manitoba over a two-year period. Predator movement was quantified using bi-directional Malaise traps and mark-release-recapture experiments. My results revealed that there was a strong to moderate suppression of soybean aphids across the gradient of landscape complexity studied. I found that predator movement between soybean and adjacent habitats was as important as landscape characteristics in explaining aphid suppression. My results indicate that the direction of predator movement in soybean field borders is influenced by the type of adjacent habitat and by predator identity. My findings highlight the importance of pest control services provided by aphidophagous predators in agricultural landscapes.