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Labrie G.,Center de recherche sur les grains Inc | Estevez B.,2591 Rue Saint Donat | Lucas E.,University of Quebec at Montreal
Agriculture, Ecosystems and Environment | Year: 2016

Strip cropping could be used to deliver several eco-services, including reducing pest pressure. The objective of this study was to evaluate the impact of the management of a strip cropping system of soybean, wheat, corn and vetch on soybean aphid Aphis glycines Matsumura, its natural enemies and on the harvest of soybean. Experimental set up of 18 m and 36 m strips were installed in 2006 on an organic farm at Les Cèdres, Québec, Canada and compared with control plots of 180 m of soybean. Each plot was replicated two times on the farm and measured 1 km long. Observations of soybean aphid and natural enemies were carried out on 18 plants per replicate strips and control plots during summer 2007-2010. Abundance of soybean aphid was reduced between 33 and 55% in strips compared with the control plots during both high infestation years (2007 and 2009), while natural control (prey/predator ratio and parasitism rate) was more efficient in strips in 2009 and 2010. Land equivalent ratio (LER), an indicator of yield production was higher in 18 m strips than in control plots. Strip cropping could be envisaged as an effective managing tool against soybean aphid in North America. © 2016 Elsevier B.V. Source


Roberge C.,University of Quebec at Montreal | Frechette B.,University of Quebec at Montreal | Labrie G.,Center de recherche sur les grains Inc | Dumont F.,University of Quebec at Montreal | Lucas E.,University of Quebec at Montreal
Insect Science | Year: 2016

Coccinellid pupae use an array of defensive strategies against their natural enemies. This study aims to assess the efficiency of gregarious pupation as a defensive mechanism against intraguild predators and cannibals in coccinellid. The study was designed specifically (i) to determine the natural occurrence of gregarious pupation in the field for different coccinellid species, and (ii) to evaluate the adaptive value of gregarious pupation as a defensive mechanism against 2 types of predators (i.e., cannibals and intraguild predators). In the field, gregarious pupation consisted of a group of 2–5 pupae. The proportion of gregarious pupation observed varied according to species, the highest rate being observed with Harmonia axyridis Pallas (Coccinellidae; 14.17%). Gregarious pupation had no impact on the probability that intraguild predators and cannibals locate pupae. Intraguild predation occurred more often in site with gregarious pupation, while cannibalism occurred as often in site with gregarious pupation as in site with isolated pupa. However, for a specific pupa, the mortality rate was higher for isolated pupae than for pupae located in a gregarious pupation site both in the presence of intraguild predators and in the presence of cannibals. The spatial location of pupae within the group had no impact on mortality rate. Since it reduces the risk of predation, it is proposed that gregarious pupation act as a defensive mechanism for H. axyridis pupae. © 2015 Institute of Zoology, Chinese Academy of Sciences Source


Chen D.,Henan University of Science and Technology | Chen D.,Sichuan Agricultural University | Hu X.,Sichuan Agricultural University | Wang X.,Agriculture and Agri Food Canada | And 9 more authors.
Journal of Food, Agriculture and Environment | Year: 2015

Twenty-six spring wheat (Triticum aestivum L.) germplasm lines, including eight known cultivars were evaluated for their agronomic performance, namely yield and quality traits as well as their resistance to fusarium head blight and leaf rust during the 2012 and 2013 growing seasons in Eastern Canada. Six of the lines, namely FL62R1, ‘Fuzion’, ‘Helios’, ‘Mégantic’, ‘Nass’ and ‘Quantum’ were tested only for fusarium head blight and leaf rust and were not tested in the field because the seeds were unavailable. The cultivar ‘Morocco’ was added as a check because of its susceptibility to leaf rust. Lines AW774, AW775 and HY162-HRF had the highest yield, followed by AW759 and CRGB-08C.159. The least lodging was observed for ACS11614, CM20809 and HY162-HRF. Lines AW769, AW759 and AW765 originated from Eastern breeding program ranked among the tallest compared to CM20809, ‘AC Carberry’, ACS10604, ACS11614 and ACS12642 which had the shortest plant height. Days to heading for the tested lines ranged from 51.8 for ‘AC Carberry’ to 60.5 for AW765. The most FHB-infected lines were ‘Quantum’ followed by CM20809 and HY162-HRF and the most resistant line was FL62R1, which showed the fewest fusarium head blight symptoms and lowest deoxynivalenol content in grains followed by AW765. A negative correlation was also observed between height and fusarium head blight (-0.69) and deoxynivalenol. The susceptible check cultivar ‘Morocco’ scored as moderately to very susceptible to the five leaf rust races, whereas ‘AC Carberry’, ACS10604, ACS11614 and CM9019 showed the highest resistance to all races. © 2015, World Food Ltd. and WFL Publishers. All rights reserved. Source

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