Thesis
Manipulation of soil temperatures to influence brood emergence in the alkali bee, (Nomia melanderi cockerell)
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/102939
Abstract
There are over 6,000 acres of alfalfa grown for seed in the Touchet Valley of Walla Walla County of Washington State. Seed yields in this growing district are often 50% greater than other Pacific Northwest seed producing districts. This can be directly attributed to efficient pollination by alkali bees, Nomia melanderi. Preservation of populations of N. melanderi is crucial for alfalfa seed production in the Touchet Valley. In the spring of 2009, temperatures in Walla Walla Valley were below average, followed by a June with above average temperatures and N. melanderi emergence and active pollen foraging lagged behind the early alfalfa bloom and subsequently growers experienced reduced seed yields and economic returns. N. melanderi overwinter as prepupae and their development is dependent on soil temperature. To synchronize pollination with the complete bloom period of alfalfa, we conducted studies to manipulate soil temperatures with various treatments including chalk dust, charcoal dust, and clear plastic in spring 2010 to determine if the use of these materials on the soil surface could modify soil temperatures at depths between 15 and 30 centimeters. White chalk dust delayed bee emergence by two weeks when compared to the untreated areas and the clear plastic initiated emergence one week earlier and significantly (p<0.01) increased overall bee emergence compared to uncovered areas. In 2011, our treatments included a control, white chalk dust and several variously colored plastic agricultural mulches (clear, red, black, white on black, blue, and brown) and a second site was added. Clear plastic had a positive effect on emergence the first few weeks of the foraging season at one site (Site B), but no significant effect at another site (Site A). White chalk dust and white on black plastic plots both retained lower soil temperatures throughout the bee emergence period, and accumulated much less thermal time than the clear plastic treatment did compared to the uncovered control plots. By expediting and postponing emergence with these surface treatments to N. melanderi beds, alfalfa seed producers can prolong the foraging season of alkali bees for efficient pollination over an extended period of time and plan for peak bee emergence to correspond with peak alfalfa bloom.
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Details
- Title
- Manipulation of soil temperatures to influence brood emergence in the alkali bee, (Nomia melanderi cockerell)
- Creators
- Amber Christine Vinchesi
- Contributors
- Douglas B. Walsh (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525166401842
- Language
- English
- Resource Type
- Thesis