Master of Science (MS)


Agricultural Economics

Document Type



The research problem of this thesis was to compare strategies and costs of protecting impatiens in greenhouse culture from western flower thrips that would provide a plant of acceptable quality to the market and would address the issue of development of resistance to commonly used pesticides by evaluating biopesticides. Partial budgets based on alternative strategies were identified. Six control strategies were identified from a combination of commercial growers, research experts and biopesticide recommendations from product distributors. The research-recommended strategy 6 had the highest total production cost ($197.44), while one of the grower strategies based on conventional pesticides had the lowest total cost ($153.28). The second growers’ strategy had the second lowest total cost by relying on scouting and pesticide application as needed. This strategy used the smallest quantity of pesticides, and was expected to reduce or prevent resistance and minimize environmental impacts. Biopesticides had higher prices than conventional pesticides. Three biopesticide recommendation strategies (3, 4 and 5) were in the midrange of production cost. The treatments containing biopesticides usually had higher product and production cost than treatments that included only nonbiopesticides. An integer linear programming model was developed to determine the optimal WFT control program for impatiens. Constraints included pesticide mortality and label limits on consecutive or total applications per crop cycle. All pesticides in the linear programming solution were conventional. Biopesticides were not included in the solution because mortalities of biopesticides were far below the threshold, according to research reported through the IR4 program. The costs of using pesticides include economic product costs and environmental costs. Using biopesticides to replace conventional pesticides in a rotation scheme of conventional ones with different modes of action could reduce water and soil pollution while maintaining crop quality.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Hinson, Roger A.