Herbivore response to habitat manipulation with floral resources: a study of the cabbage root fly
Version of Record online: 3 NOV 2011
© 2011 Blackwell Verlag, GmbH
Journal of Applied Entomology
Volume 136, Issue 7, pages 481–489, August 2012
How to Cite
Nilsson, U., Rännbäck, L.-M., Anderson, P. and Rämert, B. (2012), Herbivore response to habitat manipulation with floral resources: a study of the cabbage root fly. Journal of Applied Entomology, 136: 481–489. doi: 10.1111/j.1439-0418.2011.01685.x
- Issue online: 2 JUL 2012
- Version of Record online: 3 NOV 2011
- Received: June 6, 2011; accepted: September 26, 2011.
- conservation biological control;
- crop rotation;
- pest insect
Biological control of pest insects can be improved by providing natural enemies with additional food resources such as floral nectar within the production field. However, herbivores may also benefit from this practice. The aim of this 3-year field study was to investigate if dill and buckwheat, aimed as food resources for natural enemies, could increase the densities of the cabbage root fly, Delia radicum L. (Diptera: Anthomyiidae), a severe pest on crucifers. Differences in egg density, numbers of pupae and sex ratio were compared between cabbage plots with or without flowers. Habitat manipulation by intercropping flowering plants with cabbage did not increase the overall D. radicum egg density in our 3-year study, and there were no significant differences in egg numbers between treatments in any year. No effect on the fecundity of D. radicum was observed, most likely because of the high mobility and feeding behaviour of the female flies, combined with high abundance and diversity of other food sources around the fields during this period. Despite equal egg numbers, fewer pupae were found in plots with flowers than without in one of three studied years. This finding suggests that natural enemies attacking larvae and pupae of D. radicum were either more abundant or efficient in cabbage plots with flowers.