Identifying Agronomic Practices that Conserve and ... - SaskCanola

Percent Parasitismstudy, the objective was to investigate the effects of tillage regime, seeding rate, and rowspacing on infestations of Delia spp. and population density and parasitism of thepredator-parasitoid A. bilineata.The study was Parasitism of Aleochara bilineata on Delia spp. Pupariaconducted at twosites in centralAlberta,ZeroConLacombe andVegreville. Plotswere seeded toP < 0.05barley in theyears precedingthe study. Thezero-tillage plotswere seededdirectly into thecereal stubblewith minimalSite - Yearsdisturbance ofthe surface cropresidue. Theconventionalat Lacombe and Vegreville, AB in 2007 and 2008.tillage plots were worked with at least two cultivations to a depth of approximately 8 cmprior to seeding. Plots at Lacombe were seeded with a Conserva Pak® no-till drillwhereas plots at Vegreville were seeded with a double-disc no-till drill.Figure 8. Mean percent parasitism of Aleochara bilineata on Delia spp. pupariain Brassica napus plots seeded under conventional (Con) and zero (Zero) tillageRow spacings used in the study were 22, 30, and 45 cm, and seeding rates were 2.5, 5.0,7.5, and 10.0 kg per ha. Seed number was adjusted for each seeding rate and row spacingto achieve target canola densities of 60, 120, 180, and 240 plants per square meter. Foreach plot, plant emergence counts, canola seed yield, 1,000 kernel weight, and canolaseed oil and seed protein contents were collected. In addition, assessments of root maggotoviposition, root maggot damage ratings, rove beetle activity density and parasitismlevels on root maggot puparia were also conducted.The study results showed that the predator-parasitoid A. bilineata is important forreducing populations of root maggots in canola in central Alberta. Parasitism rates of 38to 74% were found for Delia spp. puparia and in some site-years large numbers of adultsindicated vast numbers of root maggot eggs were removed by these insects. In general,there was a higher percentage of parasitism of Delia spp. by A. bilineata observed in zerothan in conventional tillage. There were no consistent effects observed on A. bilineataactivity in relation to seeding rate and row spacing.The study also found canola yields in relation to seeding rate and row spacing to bevariable. The research found no evidence to conclude that tillage regime had a significanteffect on canola seed yield. However, the research showed that adopting zero or reduced