The time-varying survival rates of the carrot weevil, Listronotus oregonensis, were estimated by a new method. This method precluded the possibility of negative simulation survival rates. Analysis of carrot weevil population dynamics indicated that the egg mortality was density dependent with Anaphes sordidatus, an egg parasitoid, as a major density dependent factor. Larval mortality was less density dependent. Based on the mortality information, a simulation model for carrot weevil population dynamics was established. The simulation precision, evaluated by comparing simulated and observed egg and larval population dynamics, was satisfactory. Sensitivity analysis indicated that A. sordidatus had a large influence on carrot weevil population dynamics. The economic threshold for carrot weevil control in early carrots was 5 eggs/100 carrots at the peak population density. It ranged from 3.8 to 5.3 eggs/100 carrots in mid-season carrots depending on the selling price. A decision model showed that the best sowing date was after June 5 when risks were not considered. For risk aversion growers, sowing carrots between May 20 and May 31 was the best choice.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74555 |
| Date | January 1990 |
| Creators | Zhao, Dingxin |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Entomology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001116842, proquestno: AAINN66451, Theses scanned by UMI/ProQuest. |
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