Introduction
Turfgrasses are unique in their capability of tolerating foot traffic and physical wear, while still remaining functional and aesthetically pleasing. Dollar Spot (Sclerotinia homoeocarpa) is the most damaging, persistent, and costly fungal disease in the turfgrass industry. The recent move toward reducing chemical usage within the turfgrass industry in addition to local and regional governments banning the use of pesticides for maintaining turfgrass areas has resulted in the need to develop more “green” technology. To combat this fungal pathogen. The use of compost tea is one type of “green” technology that has shown potential as a Dollar spot control, but its efficacy in the field has been found by Atlantic region turfgrass managers to be inconsistent. Although much research has been done elsewhere investigating compost tea’s efficacy toward reducing dollar spot related to stimulating microbial activity in the soil and on the turfgrass blades, very little work has been done related to the physio-chemical properties of the tea or induced physiological changes in the turfgrass.
Hypothesis
The compost tea will help the plant negate any harmful effects of the disease.
Objectives
- To determine if the compost tea can help the plant survive the presence of the toxic metabolite
- To determine any effects on the plant in terms of growth that may be effected by the tea as well
Materials and Methods
- The fungus was incubated in potato dextrose broth for a period of 15 days at 26⁰C and shaken at 90 rpm (Figure 1)
- The solid mycelium mass was then separated from the liquid portion of the broth with a cheese cloth filtration
- The liquid portion was then extracted with ethyl acetate using a simple extraction method (Figure 2)
- The effects of the toxin are then tested by placing a healthy plant grown in liquid culture in a tube with liquid growth media and toxin at 100mg/ml concentration (Figure 3)
- Creeping bentgrass seed was sterilized and 10 seeds were placed on filter paper pads in glass magenta jars and tightly capped (Figure 4)
- The jars contained half strength MS media, 20% or 40% sterilized cow compost tea or distilled water depending on treatment and toxin at a total volume of 4ml
- Grass was incubated for a period of 3 weeks then harvested and measurements were taken
- Compost tea was brewed in an open system (Figure 5) using a 1:5 Compost to water ratio with molasses and aerated for 24 hours
- It was then filtered through cheese cloth at autoclaved for 20 minutes to sterilize (Figure 6)
Results and Discussion
- The compost tea at both concentrations resulted in an increase in the blade length of the plants with 40% resulting in the highest (Figure 7)
- The 40% cow tea also resulted in significantly longer roots in the presence of toxin than those seen in the control and 20% concentrations (Figure 8)
- The presence of the toxin and the teas had no effect on the germination of the seeds as shown in the last (Figure 9)
- The compost tea in this experiment was completely sterilized therefore the mechanisms at work to provide the plants with the ability to better withstand the presence of this damaging toxic metabolite are most likely physio-chemical in nature due to the fact that microorganisms have been removed from this system
Conclusion
The compost tea at the highest concentration allowed the grass to better withstand the effects of the toxin and in a field setting may result in quicker recovery and fewer symptoms of disease.
Acknowledgements
Thank you to the members of the NSAC Marine Bio-products Research Lab, the Atlantic Turfgrass Research Foundation, NSERC , CTRF and NSDA for funding the project.