<p>Field experiments were conducted to investigate the effects of Cry1Ab toxin of Bacillus thuringiensis expressed in transgenic sweet corn (Attributeä) on larval dispersal and larval density of the fall armyworm, Spodoptera frugiperda (Smith), which could affect rates of adaptation to Bt corn. Crop phenology and agronomy were also tested to determine the affects of rapid corn maturation and tillers on insect survival. Behavior and dispersal of larvae from the neonate to 10 day-old larval stage was measured in single variety plots of Bt and conventional plants. Each plot was artificially infested with one egg mass to test the hypothesis that Bt toxins affect larval behavior, increasing dispersal of early instars. Results indicated that crawling behavior of neonates was similar in both varieties but larvae settled faster on conventional plants. Larval dispersal among plants was also statistically similar in both varieties at all sampling dates. In separated plots, two larval densities and three planting dates were studied. Mortality of fall armyworm larvae in Bt sweet corn was not density-dependent. Early entry of the corn plant into reproductive stage apparently affected larval survival. There is not differential larval utilization and survival in tillers versus main whorls of Bt and non-Bt plants. Insect adaptation to Bt toxins is likely affected by larval dispersal and rapid maturation of corn plants.<P>
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-20020124-155923 |
| Date | 29 January 2002 |
| Creators | Cabrera, Juan Carlos |
| Contributors | George Kennedy, Fred Gould, John Van Duyn, George Wilson |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-20020124-155923 |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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