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Fred T. Davies Jr., Chunajiu He, Amanda Chau, Kevin M. Heinz, and Andrew D. Cartmill

This research details the influence of fertility on plant growth, photosynthesis, ethylene evolution and herbivore abundance of chrysanthemum (Dendranthema grandiflora Tzvelev `Charm') inoculated with cotton aphids (Aphis gossypii Glover). We tested five fertility levels that consisted of 0%, 5%, 10%, 20%, and 100% (375 ppm N) of recommended nitrogen levels. Aphid abundance was greatest at high fertility. Fertility affected the vertical distribution of aphids. A higher population of aphids were observed in physiologically mature and older leaves at low fertility, whereas at high fertility young leaves had 33% more aphids than older, basal leaves. Aphids depressed plant vegetative and reproductive growth, and altered carbohydrate partitioning at high fertility. Aphid-inoculated (AI) plants at high fertility had increased specific leaf area [(SLA), i.e., thinner leaves] and greater leaf area than aphid-free (NonAI) plants. Aphids caused greater ethylene production in reproductive buds and young leaves of high fertility plants, but had no effect on ethylene evolution in physiologically mature or older, basal leaves. Plant growth, leaf nitrogen (N), phosphorus (P), iron (Fe) and manganese (Mn) increased at higher fertility, as did chlorophyll and photosynthetic rates. Leaf N was highest in young and physiologically mature leaves compared to basal leaves. Aphids decreased leaf N and P. Aphids reduced photosynthesis in young leaves of high fertility plants, whereas physiologically mature and older leaves were unaffected.

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James D. Spiers, Fred T. Davies, Scott A. Finlayson, Chuanjiu He, Kevin M. Heinz, and Terri W. Starman

This research focused on the effects of nitrogen fertilization on jasmonic acid accumulation and total phenolic concentrations in gerbera. The phytohormone jasmonic acid is known to regulate many plant responses, including inducible defenses against insect herbivory. Phenolics are constitutive secondary metabolites that have been shown to negatively affect insect feeding. Gerbera jamesonii `Festival Salmon Rose' plants were grown in a growth chamber and subjected to either low fertilization (only supplied with initial fertilizer charge present in professional growing media) or high fertilization (recommended rate = 200 mg·L-1 N). Plants were fertilized with 200 mL of a 15N–7P–14K fertilizer at 0 or 200 mg·L-1 N at each watering (as needed). Treatments consisted of ±mechanical wounding with a hemostat to one physiologically mature leaf and the subsequent harvest of that leaf at specified time intervals for jasmonic acid quantification. Total phenolics were measured in physiologically mature and young leaves harvested 0 and 10 hours after ±mechanical wounding. Low-fertility plants had reduced aboveground dry mass, were deficient in nitrogen and phosphorus, and had about a 10× higher concentration of total phenolics when compared to high fertility plants. In low-fertility plants, young leaves had greater concentrations of phenolics compared to physiologically mature leaves. There were no differences in total phenolics due to wounding. The effect of nitrogen fertilization on jasmonic acid accumulation will also be discussed.

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James C. Sellmer

, Southwest, and Pacific Northwest). Appendix two is a table of butterflies and moths and their hosts, and appendix three provides some unpublished data from the author's research on insect herbivory on woody native and alien species in his backyard and

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Thomas E. Marler and Nirmala Dongol

Solidago altissima L. plants after release from herbivory. Our study illuminates an opposing scenario, where the natural lack of phytophagous insect herbivory of this island endemic tree results in no observable phytotoxic residues, but herbivory of the

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Fernando A. De Villena, Vincent A. Fritz, Jerry D. Cohen, and William D. Hutchison

the response of cruciferous vegetables to insect herbivory because of its relatively high gluconasturtiin concentration compared with other cultivars (V.A. Fritz, personal communication). A preliminary study was conducted in 2002 to determine the

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Emily C. Baisden, Douglas W. Tallamy, Desiree L. Narango, and Eileen Boyle

for herbivores to locate and populate. Table 1. Treatments, plant species, and cultivars compared with straight species in terms of insect herbivory (abundance, species richness, and cumulative seasonal damage) in a common garden as well as with

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D. Michael Glenn

Indirect effects of insect herbivory on leaf gas exchange in soybean Plant Cell Environ. 28 402 411 Baker, N.R. 2008 Chlorophyll fluorescence: A probe of photosynthesis in vivo Annu. Rev. Plant Biol. 59 89 113 Baker, N.R. Rosenqvist, E. 2004 Applications of

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James F. Cahill and Eric G. Lamb

processes, and ecosystem properties John Wiley and Sons Chichester Haag, J.J. Coupe, M.D. Cahill, J.F. 2004 Antagonistic interactions between competition and insect herbivory on plant growth J. Ecol. 92 156

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Manjul Dutt, Daniel Stanton, and Jude W. Grosser

compared with the control. In several plant species, juvenile reddening decreases as the leaves mature ( Chalker-Scott, 1999 ) and this plays a role in the tender leaf’s defense from insect herbivory and excessive light ( Karageorgou and Manetas, 2006

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Leonardo Lombardini, Astrid Volder, Monte L. Nesbitt, and Donita L. Cartmill

Citrus canker—A review J. Appl. Hort. 5 52 60 Delaney, K.J. Haile, F.J. Peterson, R.K. Higley, L.G. 2008 Impairment of leaf photosynthesis after insect herbivory or mechanical injury on common milkweed, Asclepias syriaca Environ. Entomol. 37 1332 1343