Proc. R. Soc. B doi:10.1098/rspb.2009.16311 (2009)

Some organic-farming advocates have suggested that the nitrogen spike released from synthetic fertilizers attracts more insect pests to conventionally farmed crops. Joanna Staley at Imperial College London and her collaborators compared the abundance of insect pests on two sets of cabbage plots treated with either synthetic or organic fertilizer, including manure, over two seasons.

Different insects showed different preferences: one aphid species visited the organic cabbages more often in one year, but not in the other, while another aphid preferred synthetically fertilized plots, but only in one season. Such mixed results show that the impact of fertilization type on crop pests cannot be oversimplified.