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This session sponsored by  |
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Highlights from the 2021
Research Poster Session
To view all the reports visit
www.CanadianGreenhouseConference.com |
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Raj Vansiya
Agriculture & Agri-food Canada
Vineland Station, ON
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Monitoring ToBRFV in Greenhouses Using Bumblebees
The tobamovirus Tomato brown rugose fruit virus (ToBRFV) is a devastating pathogen of tomatoes. ToBRFV is a highly regulated virus around the world due to its severe ability to impact tomato production and marketability. Recently, two ToBRFV outbreaks were identified at commercial greenhouses in Ontario and Quebec. Due to the high transmission rate of ToBRFV, early detection of infection and regular monitoring is imperative for limiting spread. Bumblebees are commonly used as pollinators in greenhouses and visit multiple plant individuals to collect pollen to return to the hive. ToBRFV is present in pollen grains derived from infected plants, and monitoring for ToBRFV in greenhouses using bees can be more efficient than manual screening for symptoms. Commercial bumblebee hives were collected from ToBRFV infected greenhouses to evaluate different detection methods. RNA sequencing of bumblebees allowed for the detection of Tomato ringspot virus, Pepino Mosaic Virus, ToBRFV, and many others. These suggests that plants within the greenhouse may be infected with some of the viruses detected. ImmunoStrip tests can be conducted on to pinpoint specific plants which are infected. To determine the limits of detection through bee samples, an experimental system using Pepino mosaic virus is currently being developed. The use of bees as a sample material allows for quick and accurate detection of pathogens within agricultural systems and can be developed into an easy-to-use monitoring system for growers and researchers.
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Alexander Nauta
University of Guelph, ON
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Development & Evaluation of a New Greenhouse Energy Model with Data from Four Ontario Greenhouses
Modelling the energy use and interior conditions of a greenhouse can be an important tool for growers, making it possible to assess the impact of changes to the greenhouse systems and operation, potentially identifying ways to save money on energy costs. In this study, a lumped capacitance thermal model is developed to simulate greenhouse interior conditions based on exterior weather and operating settings. Heat and moisture transport equations were applied to each layer of the model, with the corresponding change in temperature or absolute humidity calculated at each time step. Measured time-series data from four different greenhouses in southern Ontario were used to evaluate model performance. The measured interior temperature and relative humidity data were used to evaluate the accuracy of the model simulations, while other measured data, such as wind speed and solar radiation, were used as model inputs. Physical properties of the greenhouses were included in the model. Some required parameters, such as the infrared emissivity of the glazing, were sourced primarily from literature. The studied greenhouses included two commercial greenhouses and two smaller, passive greenhouses. Simulations of the commercial greenhouses accounted for the presence of energy curtains, evaporative cooling pads, forced ventilation, crop evapotranspiration, supplementary lights and heating, and a CO2 burner. The simulations and evaluation results for each greenhouse will be presented. It was found that the current model version has comparable or better accuracy than prior models in the literature. Plans to apply the model in a predictive mode to examine potential energy efficiency improvement by adding technology or changing operating protocols will also be briefly presented.
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Ashley Summerfield
Vineland Research & Innovation Centre
Vineland, ON
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Peeling Back the Layers of Onion Thrips IPM
Over the last several years, Onion thrips (OT) have been an emerging pest in greenhouse ornamentals. Biocontrol-based IPM programs that usually work well for western flower thrips (WFT) haven't been as effective for OT, leaving growers little choice but to apply insecticides. Due to our reliance on biologicals to manage WFT and other pests, frequent pesticide use is not a sustainable long-term solution. Knowing which parts of the WFT IPM programs are effective for OT management can help us develop a more effective program for this pest. In this study, the core components of the WFT IPM program - predatory mites and biopesticides - were tested against both OT and WFT in laboratory and greenhouse trials. Results presented compare how biocontrol agents perform against each thrips species to indicate how IPM strategies may be modified for greenhouses that are struggling to manage OT.
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Taro Saito
Vineland Research & Innovation Centre
Vineland, ON
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A New Biocontrol Agent: Generalist Predatory Mite Anystis Baccarum
Anystis baccarum is a globally distributed generalist predatory mite which reproduces without mating. The mite eats a broad range of pests, including western flower thrips, foxglove aphids, spider mites, echinothrips, and mealybugs. In laboratory trials, A. baccarum not only out-performed both Neoseiulus cucumeris and Amblyseius swirskii against all larval and adult stages of western flower thrips, but also readily consumed all foxglove aphid life stages with preference for the first instars. In greenhouse trials, significantly better control of thrips and two-spotted spider mites was obtained on chrysanthemums when A. baccarum was used together with N. cucumeris sachets. On greenhouse sweet peppers, combined releases of A. baccarum and Aphidius ervi effectively eliminated foxglove aphids, and higher fruit yields were obtained compared to plants protected by the parasitoids only. The mite also fed on naturally occurring thrips during the trial, reducing thrips feeding damage on the fruits. The results demonstrated that A. baccarum will be a useful addition to greenhouse IPM programs.
Although the mass rearing of A. baccarum was once deemed not economical due to the high cannibalism rate, we have successfully developed a prototype product, and now our project partner, Applied Bio-nomics Inc. is currently developing a production line.
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Brian Lynch
Vineland Research & Innovation Centre
Vineland, ON
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Computer Modelling of Cucumber (Cucumis Sativus) Plant Structure
Computer simulations are a useful tool for many applications, most notably robotics and automation systems development. Building a simulated model of a robot, its surrounding environment, and the interaction between the two can provide a means of testing design concepts and control processes without the risks associated with using real-world systems. This is especially true in the development of robotics and automation solutions for horticulture, where mistakes can be costly during testing as plants take time to grow and can be prone to damage by a robot. By providing a simulated environment for testing, the methods used for tasks such as automated harvesting can be developed through iterative design more easily, without risk, and free of the time constraints of growing or regenerated plants. This poster presents a computer model developed at Vineland Research and Innovation Centre for use within our robotic cucumber harvesting project. The plant structure of the cucumber plant (cucumis sativus) is modeled using an L-systems approach, which treats the growth of the plant similar to a fractal structure. Elements of the plant such as internodes, leaves, and fruit are prescribed empirical equations that capture their size over time and are evolved as the plant grows from seedling to its full size. Coefficients for these equations are fitted from measurements of real plants to mimic the true plant structure matching its growth in our greenhouse environment. Furthermore, we include modelling of the high-wire growing technique including lowering and de-leafing, resulting in a virtual crop that can be used for simulating vision and robotics systems interacting with the model for harvesting.
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