Cruciferous vegetables (Brassicaceae) are economically highly important crops that are grown worldwide and are often a part of our daily diet. Growing these vegetables, however, are not easy for farmers as these crops are commonly attacked by many insect pests. Pieris canidia is one of such pests that can be found in several Asian countries. Adult females of P. canidia lay their eggs on cruciferous vegetables, and the emerging larvae consume the leaf tissue, causing crop damage.
Economically costly and environmentally unfriendly chemical insecticides have been the major strategy to control for this pest and lower damage to crops. As an environmentally friendly strategy, agroecologists have suggested that promoting natural enemies (e.g. predators and parasitoids) by preserving natural or semi-natural habitats within the agroecosystem could lower the abundance of this pest. However, retaining such non-crop habitats is not always economically feasible for farmers as they have to keep land out of production. Instead, if the crop fields themselves can be designed to control for this pest, it can be a more economical and attractive solution for farmers. As part of such a strategy, we tested the effect of increasing crop compositional heterogeneity (i.e. the number of crop types and their evenness) on P. canidia abundance in south Chinese agroecosystems by focusing on three of the major cruciferous vegetables (i.e. cabbage, oilseed rape, and pak choi). We found a significantly negative relationship between P. canidia abundance and crop compositional heterogeneity (see Figure 1). This suggests that pest attack by P. canidia on cruciferous vegetables can be suppressed by increasing crop compositional heterogeneity. This can be achieved by incorporating structurally diverse crops into the cropping system.
Figure 1. A significantly negative relationship between Pieris canidia abundance and crop compositional heterogeneity.
Read our open access paper published in Basic and Applied Ecology , at https://www.sciencedirect.com/science/article/pii/S1439179123000075
Please cite our article as: Priyadarshana, T.S., Lee, M-B., Slade, E.M., & Goodale, E. (2023). Local scale crop compositional heterogeneity suppresses the abundance of a major lepidopteran pest of cruciferous vegetables, Basic and Applied Ecology. https://doi.org/10.1016/j.baae.2023.03.001