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

Quantification of spray drift from aerial applications of pesticide

Non-Peer ReviewedAs pesticides become more biologically active and their use becomes more widespread the impacts of spray drift become a topic of considerable interest. The drifting of sprays is a complex process; factors influencing it include meteorological conditions, application parameters, and the nature of the target. Advances in aerial application technology and in our ability to measure drift, coupled with the adoption of new technologies for regulating pesticide application spurs a desire for a greater understanding of the pesticide application process. Experiments were conducted to quantify and profile drift from aerial applications of pesticide. The effects of atomizer type, spray quality and ground cover were examined. The materials and methods essential to conduct such a project were reviewed in detail

The movement of spray drift near a live shelterbelt

Non-Peer ReviewedThere has been recent interest in the use of shelterbelts to mitigate spray drift and protect downwind areas. Previous research has investigated the interaction of spray drift and shelterbelts using model shelterbelts, wind tunnel experiments, and numerical modeling; however, there is limited knowledge on the movement of spray drift near a live shelterbelt in field conditions. These experiments measured the ground deposition and airborne concentration of drift near a live carragana/chokecherry mix shelterbelt. It was found that when compared to open field experiments where there was no shelterbelt, the mass of ground deposit was less in the lee of the shelterbelt for a distance of 0-10H downwind of the shelterbelt (where H is the height of the shelterbelt). Further than 10H downwind of the shelterbelt, the mass of ground deposit was similar to the open field. There was an 88% reduction in airborne drift exiting the shelterbelt as compared to the drift entering the shelterbelt, which likely caused the reduction in deposition in the shelterbelt’s lee. It was shown that there was a larger proportion of drift diverted over the top of the shelterbelt as compared to the drift exiting the shelterbelt. Although not apparent in these experiments, this suggested that there may be increased deposition further downwind from the shelterbelt as compared to the open field

Comparison of ground and aerial application of fungicide for control of Ascochyta blight in chickpeas

Non-Peer ReviewedAscochyta rabiei control from aerial and ground application was assessed near Saskatoon in 2003 and 2004. Each year, a site of about 12 ha was seeded to kabuli (cv. CDC Xena) chickpeas. At the first sign of disease, applications of fungicide were commenced and maintained at approximately 10-day intervals. In 2003, four applications (two with Headline (pyraclostrobin), two with Lance (boscalid)) were conducted. In 2004, the last Lance application was not done. Aerial application was made using a Cessna AgTruck applying 37 L/ha using CP nozzles emitting a spray with a VMD of approximately 271 μm. Ground applications were conducted using a Melroe SpraCoupe applying 100 L/ha using XR8003 nozzles with a VMD of approximately 246 μm. Disease ratings were done throughout the season, and seed yields were taken at crop maturity. Disease incidence progressed to 80 to 90% in the untreated plots, and fungicide application reduced disease incidence (to 20 to 30%) and increased seed yield in both years. Disease incidence and seed yield were not affected by application method in either season

Degradation of pesticides in biobeds

Non-Peer ReviewedPesticides are used to protect crops from unwanted pests thereby increasing food quality and quantity. However, one side-effect of using pesticides is their ability to pollute surface and groundwaters through diffuse (non-localized) or localized (point) sources. Biobeds were introduced in Sweden in 1993 as a means to protect the environment from point source pollution by pesticides arising from farm activities such as filling of sprayers and sprayer rinsate. A biobed is a hole in the ground into which a mixture of straw, compost and topsoil (2:1:1 by volume) is added and cover with a grass layer. The biobed mix creates a favourable environment for containment and microbial degradation of applied pesticides. The objective of this study is to investigate the relationship between active ingredient breakdown and carbon dioxide emission in both topsoil and biobed mix after pesticide application. Results indicate a five-fold reduction in the half-life of 2,4-D in the biobed mix compared to topsoil. Rapid degradation of some sulphonylurea herbicides occurred in the biobed mix despite their known persistence in soil. There was a correlation between active ingredient breakdown and carbon dioxide emission

Predicting air-borne droplet drift from agricultural areas

Non-Peer Reviewe

The supportive effects of IL-7 on eosinophil progenitors from human bone marrow cells can be blocked by anti-IL-5

Human rIL-7 was studied for its effects on myeloid and erythroid progenitors from human bone marrow cells. IL-7 did not support the granulocytic/monocytic or erythroid lineage but exclusively stimulated eosinophil colony formation (CFU-Eo) (4 ± 3 vs 48 ± 17 CFU-Eo/105 nonadherent fraction-non-T cell (NAF-NT) cells). This supportive effect was not mediated by T cells or monocytes because similar results were obtained with or without T cell or adherent depleted cell fractions. In addition, it was shown that CD34+ sorted cells could be stimulated by IL-7 (0 vs 15 ± 9 CFU-Eo/3 x 103 CD34+ cells). Furthermore studies with IL-3 or granulocyte- macrophage CSF (GM-CSF) demonstrated an additive effect on the IL-7 supported colony formation. Finally, experiments were performed with anti-IL-3, anti- GM-CSF, anti-IL-1, and anti-IL-5 to exclude the possibility that IL-7 indirectly stimulated the eosinophil progenitor cell. Anti-GM-CSF, anti-IL-1, or anti-IL-3 did not influence the supportive effects of IL-7. However, anti- IL-5 did abolish the effects of IL-7 on the eosinophil colony formation (69 ± 15 vs 3 ± 2 CFU-Eo/105 NAF-NT, n = 3). Similar results were obtained with CD34+ sorted cells. Moreover, IL-5 mRNA expression could be demonstrated in IL-7-stimulated NAF-NT cells. These data suggest that the supportive effects of IL-7 on eosinophil precursors are mediated by the endogenous release of IL-5.</p