Combining intercropping with semiochemical releases: Optimization of alternative control of sitobion avenae in wheat crops in china

Overreliance on pesticides has large environmental and human health costs that compel researchers and farmers to seek alternative management tactics for crop pests. For insect pests, increasing crop species diversity via intercropping and using semiochemicals to alter local arthropod populations have separately proven effective at reducing pest densities. Here, we combine these two tactics in an effort to gain better control of Sitobion avenae (Fabricius) (Hemiptera: Aphididae), the English grain aphid, a major pest of cereal production worldwide. We conducted field experiments over 2years testing the effectiveness of combining intercropping of wheat and oilseed rape with release of methyl salicylate (MeSA). We found that maximum and mean aphid densities were highest in wheat monocultures, significantly lower in intercropped plots and MeSA plots, and lowest when intercropping and MeSA release were combined by obtaining highest densities of predatory lady beetles and parasitoids rates. Importantly, grain yield and quality showed a similar pattern: they were highest for combined intercropped/MeSA plots, intermediate in plots with intercropping or MeSA alone, and lowest in control monoculture plots. Our results suggest that combining these two tactics holds significant promise for improved management of aphid populations and emphasize the need to integrate alternative pest control approaches to optimize sustainable insect pest management.