Effects of ground predators, abiotic factors and plant density on the flea beetles, Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae)
| dc.contributor.author | Woodland, Shayla | |
| dc.contributor.examiningcommittee | Cárcamo, Héctor (Entomology) | |
| dc.contributor.examiningcommittee | Duncan, Rob (Plant Science) | |
| dc.contributor.supervisor | Costamagna, Alejandro | |
| dc.date.accessioned | 2024-09-13T15:00:46Z | |
| dc.date.available | 2024-09-13T15:00:46Z | |
| dc.date.issued | 2024-08-14 | |
| dc.date.submitted | 2024-08-14T18:53:09Z | en_US |
| dc.degree.discipline | Entomology | |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | The crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae), and the striped flea beetle, Phyllotreta striolata (Fabricius) (Coleoptera: Chrysomelidae), are prominent economic pests to canola crops, Brassica napus, (L.) (Brassicaceae) in the Canadian prairies, by defoliating canola seedlings, resulting in recurring yield losses. Current management strategies in the Canadian prairies rely heavily on chemical control via both seed-coated and foliar spray treatments. To limit chemical pesticide applications due to potential adverse environmental effects, there has been a focus on alternative flea beetle management strategies including altering plant density and determining potential natural enemies. In addition, few studies have demonstrated how temperature and plant density affect flea beetle feeding and there is little known about the factors affecting stem feeding on canola seedlings. Laboratory studies in petri dishes and microcosms were completed to examine effects of temperature, plant density and predators on cotyledon and stem feeding by both species of flea beetles in terms of damage intensity and prevalence. Both species defoliated similar amounts, suggesting no feeding difference in species. Feeding increased with temperature and more defoliation occurred on the underside of the cotyledons. Pterostichus melanarius and Pardosa spp. reduced flea beetle abundances as well as total cotyledon defoliation. In addition, there was less cotyledon and stem damage at higher plant densities. Field studies were completed in four regions of the Canadian prairies (Lethbridge and Peace River, AB; Saskatoon, SK; and Carman, MB) over 4 years (2018 – 2021). Evidence of both the resource concentration hypotheses and a dilution effect was found as flea beetle abundance increased with plant density, yet defoliation levels generally decreased. Yield increased with plant density regardless of the management treatment or region. The knowledge gained on how flea beetles’ feeding on stems and cotyledons is affected by temperature, plant density, and predators will help for in-field scouting and assessment ratings and provide information for future research into biological control potential with the tested predators. In addition, using plant density as a flea beetle management strategy either combined with current chemical practices or as an alternative, is effective to protect yield while limiting chemical applications. | |
| dc.description.note | October 2024 | |
| dc.description.sponsorship | Canola AgriScience Cluster Program (Project ASC-02) University of Manitoba Graduate Student Completion Award | |
| dc.identifier.uri | http://hdl.handle.net/1993/38588 | |
| dc.language.iso | eng | |
| dc.rights | open access | en_US |
| dc.subject | flea beetle | |
| dc.subject | canola | |
| dc.subject | predator | |
| dc.subject | biological control | |
| dc.subject | defoliation | |
| dc.subject | plant density | |
| dc.subject | temperature | |
| dc.subject | resource concentration | |
| dc.subject | dilution effect | |
| dc.title | Effects of ground predators, abiotic factors and plant density on the flea beetles, Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae) | |
| dc.type | master thesis | en_US |
| local.subject.manitoba | yes | |
| oaire.awardNumber | 44349 | |
| oaire.awardTitle | James Gordon Fletcher Graduate Research Award in Agricultural and Food Sciences | |
| project.funder.name | James Gordon Fletcher |