Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Proceedings
Publication Acceptance Date: 11/5/2005
Publication Date: 12/5/2005
Citation: Setamou, M., Goolsby, J., Patt, J.M. 2005. Effect of host plant fertilization on the developmental biology and feeding preference of the glassy-winged sharpshooter. Proceedings of CDFA Pierce's Disease Control Program Research Symposium, December 5-7, 2005, San Diego, California. p. 101-104. Interpretive Summary: Homalodisca vitripennis Glassy-winged sharpshooter (GWSS) is native the southeastern U.S., including Texas, and an invasive pest in California where it is the primary vector for the lethal bacterial disease in grapes, Xylella fastidiosa called Pierce’s Disease. Research is being conducted to investigate the biology of this pest, including studies aimed improving rearing methods. Plant fertility plays a large role in the size and fertility of insects including GWSS. Fertilization studies of cowpeas showed that addition of urea fertilizer resulted in larger, longer lived and more fertile GWSS females. These results have been utilized by scientists and insectary managers to improve their production of GWSS, for research purposes and the production of biological control agents for release in California.
Technical Abstract: The main objective of this research was to evaluate the effect of host plant fertilization on the survival, immature development, adult fecundity, and the feeding of the glassy-winged sharpshooter (GWSS), a primary vector of Xylella fastidiosa (Xf). The development biology of GWSS was studied on cowpea plants, Vigna unguiculata, treated with three fertilization regimes (NPK alone, urea alone, and a combination of NPK and urea) along with a non-fertilized control. Fertilization affected cowpea plant growth, the total protein content, and the profile of free amino-acids in the xylem sap. The ultimate nymphal survivorship was significantly higher on fertilized plants than on control plants. In addition, newly emerged adult weight significantly increased with fertilization; specifically, GWSS nymphs reared on plants fertilized with urea yielded adults with the highest weight. NPK fertilization significantly reduced the nymphal development period for females but not for males. Females maintained on fertilized plants showed higher oviposition frequency and number of egg masses laid compared to unfertilized plants with highest oviposition potential recorded on urea treated plants. In addition, significantly bigger egg mass sizes were obtained from fertilized plants. Consequently, GWSS populations that developed on fertilized plants and more so on urea treated plants had a higher intrinsic rate of increase compared to those developing on unfertilized control plants. In choice tests, adult GWSS showed a preference for fertilized cowpea plants. The number of GWSS adults per plant and the proportion of plants infested were significantly higher for plants that received fertilization compared to the non-fertilized control plants. However, no feeding preference was recorded for nymphs.