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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #219896
Title: Nitrogen and water affect direct and indirect plant systemic induced defense in cotton

Author
item Olson, Dawn
item CORTESERO, A - UNIV DE RENNES
item RAINS, G - UNIV OF GA
item Potter, Thomas
item Lewis, Wallace

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2009
Publication Date: 2/20/2009
Citation: Olson, D.M., Cortesero, A.M., Rains, G.C., Potter,T., Lewis, W.J. 2009. Nitrogen and water affect direct and indirect plant systemic induced defense in cotton. Biological Control. 49:239-244. DOI:10.1016/j.biocontrol.2009.02.011.

Interpretive Summary: Plants have numerous chemical defenses against herbivores and pathogens, which can substantially aid in their ability to defend themselves. However, very little is known about the affects of fertilizer and water levels on these defenses. We tested the affects of nitrogen levels and water availability on the ability of cotton plants to deter feeding by Spodoptera exigua through induction of anti-feedant chemicals, and to attract the biological control agent, Micropitis crociepes through induction of chemical volatile emission. Cotton plants were grown with various nitrogen levels and had water stress or normal water, and were fed upon by S. exigua larvae. Both water stress and nitrogen levels under and over the recommended levels increased leaf tissue consumption and decreased attraction of M. crociepes to the cotton plants. Water stress showed an increase in larval feeding compared to plants with normal water. Chemical analyses of volatiles released from herbivore damaged plants indicate that their concentrations differ among the nitrogen levels with the control, low and high nitrogen plants having amounts much lower than the plants with the recommended nitrogen level. Effective biological control of pests depends on these chemical defenses and therefore proper water and nitrogen levels need to be considered in crop production.

Technical Abstract: We tested the affects of nitrogen levels and water availability on the ability of cotton plants to deter feeding by Spodoptera exigua larvae through induction of anti-feedant chemicals by the cotton plant, and to attract the biological control agent, Micropitis crociepes through induction of chemical volatile emission. Cotton plants were grown with 0, 1 and 2 times the recommended nitrogen levels and had water stress or normal water. Choices of leaf tissue from the various nitrogen and water treatments were provided to S. exigua larvae. Choices of the plants with various nitrogen and water treatments were provided to M. croceipes in flight tunnel bio-assays. Both water stress and nitrogen levels under and over the recommended levels increased leaf tissue consumption by the S. exigua larvae, and decreased attraction of M. crociepes to the cotton plants. Water stress showed an increase in larval feeding compared to plants with normal water. Gas Chromatograph and Mass Spectrometer analyses of the chemical volatiles released from herbivore damaged plants indicate that their concentrations differ among the N levels with the control, 0N and 2N plants having amounts much lower than the 1N plants. Because plant chemical defense mechanisms are negatively affected by improper nitrogen and insufficient water, these factors will need to be considered in biologically-based pest management.