Disease forecasting and the role of pollinators in the spread of blossom blight of seed alfalfa in Southern Alberta

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dc.contributor.authorReich, Jonathan
dc.contributor.authorUniversity of Lethbridge. Faculty of Arts and Science
dc.contributor.supervisorChatterton, Syama
dc.contributor.supervisorJohnson, Dan L.
dc.date.accessioned2015-09-30T03:17:17Z
dc.date.available2015-09-30T03:17:17Z
dc.date.issued2015
dc.degree.levelMastersen_US
dc.description.abstractBlossom blight of seed alfalfa (Medicago sativa L.), caused by fungal pathogens Botrytis cinerea Pers.:Fr. and Sclerotinia sclerotiorum (Lib.) de Bary, can contribute to significant yield declines in moist growing seasons. In a greenhouse study that examined the occurrence of pollen infection by B. cinerea, pollen infection was observed at very low levels (<1% of pollen infected) in suspension-inoculated treatments. When leafcutter bees (Megachile rotundata), hypothesized vectors of B. cinerea spores, were collected from seed alfalfa fields, the bees tested positive for B. cinerea but their pollen load did not. Frequency of bees carrying B. cinerea spores increased over the growing season, with 96-100% of bees from the final collections (~August 20) testing positive for B. cinerea. These patterns closely follow patterns of observed airborne B. cinerea spore concentrations as detected by a quantitative polymerase chain reaction (qPCR) assay using aerosol samples collected from seed alfalfa fields. A sensitive, species-specific primer and probe for S. sclerotiorum was designed for use in the same qPCR assay. Discharge of S. sclerotiorum in one field closely followed the discharge of B. cinerea spores, with several larger (>200 ascospores per day) discharge days observed beginning in mid-July and continuing to the end of August. In the other two fields surveyed, discharge of S. sclerotiorum was concentrated in one or two large events. It is concluded that pollen infection and transmission of blossom blight pathogens by leafcutter bees are not large contributors to the spread of blossom blight in southern Alberta. In addition, using qPCR to quantify airborne inoculum levels will likely be useful in developing a disease forecasting model for blossom blight of seed alfalfa.en_US
dc.description.sponsorshipAlberta Crop Industry Development Fund and the Alfalfa Seed Commission (Alberta); Grant number 2013F051Ren_US
dc.embargoNoen_US
dc.identifier.urihttps://hdl.handle.net/10133/3756
dc.language.isoen_CAen_US
dc.proquestyesNoen_US
dc.publisherLethbridge, Alta. : University of Lethbridge, Dept. of Geographyen_US
dc.publisher.departmentDepartment of Geographyen_US
dc.publisher.facultyArts and Scienceen_US
dc.relation.ispartofseriesThesis (University of Lethbridge. Faculty of Arts and Science)en_US
dc.subjectdisease forecastingen_US
dc.subjectpollinatorsen_US
dc.subjectleafcutter beesen_US
dc.subjectfungal pathogensen_US
dc.subjectseed alfalfaen_US
dc.subjectblossom blighten_US
dc.titleDisease forecasting and the role of pollinators in the spread of blossom blight of seed alfalfa in Southern Albertaen_US
dc.typeThesisen_US
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