Crop Diversity and Land Simplification Effects on Pest Damage in Northern China

Agricultural intensification has brought obvious increases in the extent and intensity of agricultural activities, which simultaneously led to rapid changes in landscape patterns. However, the relationship between agricultural intensification and pest damage was poorly known at the landscape scale, especially in China. We conducted an analysis to examine the relationship between agricultural intensification and pest damage of six pest species by using statistical data from1987 to 2012 in China. Results showed that high crop diversity could significantly suppress damage of oligophagous pests such as cereal aphids, rice stem borers, and corn borers while having no effects on polyphagous pests such as cotton bollworms and armyworms except for cotton aphids. Landscape simplification has no significant effects on pest damage except cotton bollworms, and there was no interaction between crop diversity and landscape simplification. Moreover, the relationship between crop diversity and crop yields per hectare was significantly negative. The canonical correspondence analysis ordination diagram showed that pest species responded to the crop species differently. These results suggest that crop diversity have potential for sustainable pest management with complete prevention of pest damage on crops, and it is environment friendly.