Écologie de la communauté de thrips des fleurs inféodée à l'agroécosystème des fraisières : composition, phénologie et influence des fleurs sauvages sur la colonisation de la culture

Authors: Canovas, Morgane
Advisor: Cloutier, ConradFournier, Valérie
Abstract: Anthophagous thrips are serious pests. Their opportunistic associations with inflorescences of diverse host plants require to consider their presence in both cultivated and wild areas of the agricultural landscape. Wildflowers, naturally occurring in uncultivated field margins, are capital resources supporting thrips populations close to crops. However, thrips communities associated with agroecosystems are not well known, particularly in Quebec where thrips damage to strawberries is problematic. The phenology of the anthophagous thrips community, and its use of floral resources, were monitored in strawberry fields agroecosystems (i.e. strawberry field and adjacent uncultivated margins) in Orléans Island, Québec, Canada. In an original way, ecological factors related to wildflowers were used as predictors to model pest thrips density and their distribution within strawberry fields. Thrips community is composed of eleven species, dominated by pests present all year round: Frankliniella tritici and F. intonsa, the latter being observed for the first time in eastern Canada. Thrips species richness and abundance on the wild flora are high, some flowers supporting most of the thrips community. Frankliniella spp. have a wide wildflower host range, with preferences towards particular species. There are significant relationships between the number of Frankliniella spp. present on wildflowers and their density increase in strawberry. Thrips density in strawberry flowers decreases when moving away from the uncultivated margins. We demonstrated that wildflowers should be considered as thrips sources in strawberry fields agroecosystems. Knowing the associations between Frankliniella spp. and wild flora, as well as their distribution within strawberry fields, are undeniable advantages for crop management. The optimal manipulation of flowering margins is a promising research avenue to reduce strawberry colonization by pest thrips and recreate a natural control dynamic of their populations.
Document Type: Mémoire de maîtrise
Issue Date: 2021
Open Access Date: 10 January 2022
Permalink: http://hdl.handle.net/20.500.11794/71423
Grantor: Université Laval
Collection:Thèses et mémoires

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