Stubble burning and tillage effects on soil organic C, total N and aggregation in northeastern Saskatchewan

Non-Peer Reviewe

Spray application methods to maximize Sclerotinia control in canola with foliar fungicide

Non-Peer ReviewedVinclozolin (Ronilan) and benomyl (Benlate) fungicides were applied to canola with 5 application methods to determine the impact of nozzle type and pressure on Sclerotinia stem rot suppression over 3 seasons in north-east Saskatchewan. A spray deposition study was conducted under controlled conditions, which showed that the majority of spray was intercepted by the top third of the canola canopy for all application systems, with a slight increase in the amount deposited on the upper flowers with elevated spray pressure. Flowers and buds retained nearly 20% of the total applied spray dose, and leaves retained most of the remainder. Stems retained a very minor proportion of the applied dose. Coarser sprays delivered more of their dose in the target area, but had lower retention values on flowers and buds than the finer sprays. In field experiments fungicide effectiveness varied with environmental conditions each season but both products were generally equally effective in 1998 and 2000, reducing stem rot incidence and increasing yield over that of untreated plots. In 1999 neither fungicide was effective for Sclerotinia control likely due to the prevailing environment that was conducive to heavy disease development. Overall, conventional flat fan nozzles (TeeJet XR) and low-drift venturi nozzles (Greenleaf TurboDrop) were equally effective at reducing stem rot incidence. There was a trend to improved stem rot control and increased yield for each nozzle when operated at elevated pressure. Based on these results, venturi nozzle technology is appropriate for use with foliar fungicides for Sclerotinia stem rot control in canola provided pressures are adjusted to optimize nozzle performance

Fungicide and variety effects on foliar diseases and yield of wheat and barley

Non-Peer Reviewe

Determining the race structure of Leptosphaeria maculans in western Canada

Non-Peer ReviewedEach year blackleg disease of canola (Brassica napus L.), caused by Leptosphaeria maculans (Desmaz.) Ces. & De Not., is responsible for significant yield loss of Brassica napus L., oilseed rape and canola worldwide. In western Canada, blackleg disease has been managed using a combination of four-year rotations and resistant canola varieties. To determine the current race structures present in western Canada, isolates were collected from eight locations across Alberta, Saskatchewan, and Manitoba in 2007 and 2008. These isolates were inoculated onto eight different canola varieties containing different resistant genes: ‘Westar’, ‘Quinta’, ‘Glacier’, ‘MT29’, ‘Samourai’, ‘Quantum’, ‘Falcon’ and ‘Darmor’. Using the gene-for-gene theory, race structure was determined based on variety resistance to L. maculans. A scale of 0 (no disease symptoms) to 9 (severely diseased) (Newman 1980) was implemented to assess plant resistance, with a score of 5 and above suggesting susceptibility. Preliminary results have identified 18 different races, nine of which contain the majority of isolates. These results have also shown that the frequency of L. maculans avirulent alleles greatly varies between the different sites in western Canada

Optimizing canola and field pea production: disease implications of intensive canola and field pea rotations

Non-Peer Reviewe

Impact of tillage system, rotation and fungicide application on seed yield and protein content of wheat and field pea

Non-Peer ReviewedThe impact of tillage system, increasing broadleaf crop rotation frequency and foliar fungicide use on diseases, seed yield and protein content of wheat and field pea were determined in the second cycle of three 4-year rotations at Melfort from 1998 to 2001. A 4-replicate split-split plot design was used with three tillage systems (zero tillage (ZT), minimum tillage (MT) and conventional tillage (CT)) as main-plots, three rotations (1. barley-canola-wheat- barley; 2. barley-pea-wheat-canola; and 3. canola-pea-flax-barley) as sub-plots and foliar fungicide treatments (treated or untreated) as sub-sub plots. Tillage system had little impact on diseases in either wheat or field pea. In the drought year of 2001, seed yield of wheat was greater under ZT or MT than under CT. The trend for field pea was similar in 2001. In other years there was no difference in yield for either crop among tillage systems . Protein content of wheat was often greater under ZT than under MT and/or CT, but tillage system did not have a consistent effect on protein content in field pea seed. Rotation was not a major factor in disease severity of either wheat or field pea. Rotation had an effect on seed yield of field pea only in 2001, but there was no effect on seed yield of wheat in any year. For wheat, protein content in seed was greater in 3 of the 4 years (1998, 1999 and 2001) when it followed field pea than when it was grown after canola. Rotation had little effect on protein content in seed of field pea. Foliar fungicide application had the greatest impact on disease control and seed yields, although benefits varied from year to year. Fungicides increased field pea yield by 32 and 16% in 1998 and 2000, respectively and wheat yield by 19, 13 and 9% in 1998, 1999 and 2000, respectively. There was no yield increase for either crop by application of foliar fungicide in the drought year of 2001. For wheat, protein content in seed decreased with fungicide application, but the effect was significant only in 1998. For field pea, protein content in seed decreased with fungicide application in 1998 and 2000, most likely due to a dilution effect from increased seed production. In summary, foliar fungicides had the greatest impact of the factors examined to reduce plant disease symptoms and increase seed yield of either crop, however the magnitude of the yield increase varied among crop years depending on environmental conditions. Most importantly, the study indicated that increasing the frequency of broadleafed crops in a rotation did not result in increased diseases or lower yield of field pea

Effects of broad-leaf crops frequency on seed yield, and nitrate-N, and extractable P in soil after four years in a Black Chernozem in Saskatchewan

Non-Peer Reviewe

Determining the race structure of Leptospheria maculans in western Canada

Non-Peer Reviewe

Foliar disease control in field pea in southern Brazil

Non-Peer ReviewedThe introduction of field pea into the crop rotation in southern Brazil would diversify production and increase sustainability of the system. One of the main obstacles to field pea production in southern Brazil is the occurrence of foliar diseases. The objective of this project was to determine if field pea production potential could be maintained by application of fungicides during crop development to reduce the severity of diseases of field pea, particularly mycosphaerella blight and anthracnose. The study demonstrated that fungicide application effectively reduced severity of symptoms and maintained yield and quality. The single application of two combined active ingredients (pyraclostrobin and epoxiconazole) appeared to result in a synergy that proved to be the most effective treatment evaluated. Therefore, the use of fungicides with other integrated pest management practices such as early seeding and choice of a disease tolerant or less susceptible cultivar should help to maintain yield and quality of field pea in southern Brazil

Effects of broad-leaf crops frequency on seed yield, and nitrate-N and extractable P in soil after eight years in a Dark Brown Chernozem in Saskatchewan

Non-Peer Reviewe