Impact de différents types d'entretien de pelouses sur l'abondance et la diversité des arthropodes, et potentiel des graminées endophytiques dans la lutte aux insectes ravageurs

Authors: Rochefort, Sophie
Advisor: Brodeur, Jacques; Shetlar, David J.
Abstract: Turfgrass lawns are important ecosystems in urban areas, but the ecology of cool-season lawns has not been extensively studied in Quebec. Turfgrass management may influence ecosystem stability and arthropod communities. The first objective of this thesis was to characterize arthropod communities associated with turfgrass in Québec, and more specifically Collembola and ground beetle assemblages. Second, the effect of different turfgrass management practices on arthropods was evaluated. In a three-year field study, arthropods were sampled in two turfgrass lawns: a newly established lawn and a 10-year old lawn. Four turfgrass management were tested: i-management without pest control (control), ii-management with chemical pesticides, iii-integrated pest management, and iv-ecological management. Another aspect of this thesis was the evaluation of the potential of endophytic turfgrasses for the control of the hairy chinch bug, an important insect pest in Québec. Overwinter survival of endophytes and their host plants was first tested in two ecologically different areas under natural conditions. Furthermore, the influence of different combinations of endophytic perennial ryegrass and Kentucky bluegrass on hairy chinch bug survival and development was determined under greenhouse conditions. The study indicates that the diversity of arthropods in general, and of Collembola and ground beetle in particular was similar for both lawns even if plant composition differed. After three years, no difference between the four turfgrass management practices was detected. However, short term effects following insecticide (diazinon and carbaryl) applications appeared for Collembola and ground beetles communities. Perennial ryegrass and tall fescue have the capacity to overwinter under Québec winter conditions. The endophyte Neotyphodium coenophialum found in tall fescue didn’t persist over time while the association N. lolii–perennial ryegrass remained stable after two winters. Greenhouse experiments revealed that endophytic perennial ryegrass ‘SR 4220’ did not negatively affect hairy chinch bug survival and development.
Document Type: Thèse de doctorat
Issue Date: 2006
Open Access Date: 12 April 2018
Grantor: Université Laval
Collection:Thèses et mémoires

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