|Chen, Yigen -|
Submitted to: Recent Advances in Entomological Research
Publication Type: Book / Chapter
Publication Acceptance Date: November 22, 2009
Publication Date: August 1, 2010
Citation: Chen, Y., Ni, X. 2010. Nitrogen modulation on plant direct and indirect defenses. In: Liu, T.-X. and Kang, L., editors. Recent Advances in Entomological Research: From Molecular Biology to Pest Management. Beijing, China:Higher Education Press. p. 52-60. Interpretive Summary: Many agricultural practices including nitrogen application not only increase crop yield, but also affect the plant defense against insects and diseases. Nitrogen fertilization is one of the most common agronomic practices in crop production. This review is to focus on assessing the effect of nitrogen application on ecological interactions of agricultural ecosystems, and their ramifications in the integrated pest management. The types of plant defense and ecological and environmental consequences associated with nitrogen applications into ecosystems are discussed first. Then, the influence of nitrogen fertilization on crop plant-insect pest-natural enemy interactions, and plant direct and indirect defenses is discussed. At the end, the possibility of developing new sustainable pest management tactics through nitrogen management by minimizing the negative, and maximizing the positive components of crop plant-insect pest-natural enemy interactions is also discussed.
Technical Abstract: Instead of being passively attacked by insect pests, plants possess a myriad of defense mechanisms to protect themselves. These mechanisms function broadly either by directly reducing herbivore fitness (direct plant defense), or by indirectly attracting natural enemies of the herbivores (indirect plant defense). Many biotic and abiotic factors including nitrogen affect the expression of plant defenses. Nitrogen fertilization is by and large the most common agronomic practice in crop production. Anthropogenic use of nitrogen meets the food supply for the rapid increase in human population, while it alters plant defense capability and the global nitrogen cycle, which is increasingly threatening plant and animal biodiversity in managed and natural ecosystems. In this review, we first review types of plant defense and ecological and environmental consequences associated with anthropogenic addition of nitrogen into ecosystems. We then review the influences of nitrogen fertilization on plant-herbivore-natural enemy interactions and plant direct and indirect defenses. We finally discuss the possibility of developing new sustainable pest management tactics through nitrogen management: minimizing the negative, and maximizing the positive components of tritrophic interactions through optimized nitrogen applications in agricultural production.