Sara Stricker first attended the University of Guelph (UofG) with the goal of becoming a Veterinarian. A third year plant pathology course, and a related summer employment opportunity with Dr. Greg Boland piqued her interest in this vastly different field. Sara also discovered she loved teaching, and following her 2012 graduation from the UofG, attended the University of Western Ontario and completed a Bachelor’s degree in Education. After teaching abroad in England for a year, Sara returned to her Alma mater to continue studying plant pathology.
In the spring of 2015 Sara applied to the School of Environmental Sciences to work with Dr. Tom Hsiang, a professor and turfgrass disease specialist. Sara describes herself as “liking turfgrasses but more in love with the science of pathology.” One benefit of working with turfgrasses described by Sara is the ability for them to mature very quickly, allowing very quick succession of experiments in the lab.
Sara’s research has both lab and field components at the UofG and the Guelph Turfgrass Institute (GTI). Her research focuses on the fungus Microdochium nivale. There are two turfgrass diseases caused by this pathogen:
- Microdochium patch, which occurs with absence of snow cover, is characterized by very small irregularly shaped patches, often 1-5cm in diameter.
- Pink snow mould, which occurs under prolonged snow cover, is characterized by large circular patches, often 20cm in diameter or larger.
Sara is working with a commercially available resistance activator product called Civitas™. It is a clear, colourless liquid, consisting of food-grade isoparaffins (mineral oil) and is typically mixed with the pigment dispersal product Civitas Harmonizer™. The Harmonizer is a polychlorinated copper (II) phthalocyanine pigment, which has some fungicidal properties due to the copper component. A resistance activator is a product that is non-toxic to plants and fungi that, when applied to a plant, activates the plant’s natural resistance responses resulting in overall decreased disease symptoms. These two products in combination use invoke both the Induced Systemic Resistance (ISR) mode of action and the Systemic Acquired Resistance (SAR) pathway for inhibition of many turfgrass diseases, including dollar spot (Sclerotinia homoeocarpa), as well as some common turfgrass insect pests. This research is being conducted through a partnership with the Agriculture and Agri-Food Canada Research Station in Quebec, with funding from the Canadian Government, the Canadian Turfgrass Research Foundation and Petro Canada, and a parallel field study is being conducted in Norway.
Sara describes ISR as “rallying the troops inside the plant prior to a pest invasion,” in essence, putting the plant on high alert that it will need to combat an impending threat. ISR works very effectively during the active growing season, but one question the research will address is how the process works over the winter.
In the lab, Sara’s research has identified that the level of control of Microdochium patch by Civitas/Harmonizer™ varies by turfgrass cultivar. If this product can suppress disease symptoms of not only Microdochium patch but also pink snow mould in the field, it may prove to be an alternative to fungicides currently used in the turfgrass industry for winter disease control. Specifically, Sara’s research project will focus on the efficacy of this resistance activator to suppress symptoms caused by M. nivale under predicted climate change conditions.
Atmospheric CO2 concentrations have been on the rise since the dawn of the industrial age. As a consequence, temperate countries may experience a seasonal temperature increase between 1.5 and 4°C in the next 50 years. In addition, we may experience fluctuating winter temperatures and unstable snow cover due to this climate change. One aspect of plant resistance to plant pathogens in northern climates are the processes of cold hardening. These processes involve stockpiling nutrients and the producing pathogen-related proteins for defence against pathogens. Hardening is triggered by decreasing day length and lower temperatures. With the onset of climate change, plants may experience a shorter than optimal hardening period; temperature and daylength need to be in proper balance for grasses to go dormant. Grasses may also experience shorter periods of snow cover, weather extremes, early frost and overall warmer temperatures. These conditions have the potential to increase the severity of many plant diseases, including those caused by M. nivale.
Sara’s experiment involves the application of Civitas/Harmonizer™ on several turfgrass cultivars inoculated with M.nivale under a variety of temperature and carbon dioxide concentration conditions to mimic the conditions predicted under climate change. The aim of her research is to identify cultivars that are naturally more resistant to the diseases in conditions of temperature fluctuations and increased CO2 levels, and which turfgrass cultivars might pair best with the Civitas/Harmonizer™ on putting greens in the future – a very important consideration for Superintendents and turfgrass managers when renovating, growing-in or overseeding an existing putting green. The research may also assist in the breeding process for M. nivale resistant turf cultivars.
The current winter of 2015-2016 is the first season for Sara’s research project under field conditions. Preliminary results are not available just yet, but the expected result is that both pink snow mould and Microdochium patch will be suppressed by the Civitas/Harmonizer™. Sara explains that there are a lot of theories surrounding ISR in turfgrasses. Future research in Dr. Hsiang’s lab will focus on genetic sequencing to determine what genes are turning on inside the plant in response to the plant activator. Additional laboratory work will also examine the analyzed sugar concentrations in plants, and looking into the possibility that application of Civitas/Harmonizer™ results in an increase in fructans, which are typically produced during the process of cold hardening.
On campus Sara is a very involved graduate student and when asked about the environment, she responded, “I love it.” She passionately describes UofG as “a great dynamic of city and farm.” Sara is the Ontario Agricultural College Graduate Student Council President, and also is a representative on the Canadian Pytopathological Society Education Committee – Sara describes this appointment’s purpose “to educate the general public on plant diseases,” and speaks of this appointment with high regard. Also on the Graduate Student Council for the School of Environmental Sciences, Sara notes that “it is important as a grad student to pace yourself and talk to fellow students.”
In closing, Sara remarks that “I love teaching and would love to become a faculty member. I like being in the classroom.” The turfgrass industry will find the results of this research very important as they will have impact on disease management strategies in an increasingly regulated environment that has the need to identify alternatives to traditional fungicide applications, and to face the challenges of climate change.
Article authored and published by John R. Watson, Guelph Turfgrass Institute Communications Assistant
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