Adaptation of Wheat-Pea Intercropping Pattern in China to Reduce Sitobion avenae (Hemiptera: Aphididae) Occurrence by Promoting Natural Enemies

Abstract

The use of intercropping as a strategy for increasing biodiversity in fields has the potential to reduce pest damage and improve the crop production. Here, a study was undertaken to evaluate the role of different wheat-pea intercropping patterns in conserving arthropod natural enemies and suppressing cereal aphids in agroecosystems. Wheat-pea intercropping in an 8–2 row pattern of wheat and pea, respectively, preserved and augmented natural enemies more than a monoculture of wheat. The highest abundance of ladybeetles in 2008 and 2009 occurred in the 8–2 row pattern, whereas the highest densities of aphid parasitoids were found in the 4-2 row pattern in 2008 and the 8-2 row pattern in 2009. The distribution of aphid populations in the peak stage was spatially heterogeneous, and the highest density of aphids was shown visually in wheat monoculture fields. The land equivalent ratio of 1.121:1.187 for wheat-pea intercropping in 2008 and 1.114:1.174 for wheat-pea intercropping in 2009 showed that intercropping of wheat and pea has potential to improve the utilization of plant growth resources as compared to sole crops. Wheat-pea intercropping has potential to control English grain aphids effectively by enhancing the abundance of natural enemies, especially with an 8-2 row pattern of wheat-pea, respectively.