Pink Snow Mold ( Microdochium patch) Sam Hillard

1. Pink Snow Mold (Microdochium patch) Sam Hillard

2. Primary Hosts All Cool Season Turfgrasses: Annual Bluegrass Rough Bluegrass Kentucky Bluegrass Tall Fescue Fine Fescue Colonial Bentgrass Velvet Bentgrass Creeping Bentgrass Perennial Ryegrass

3. Pathogen/Causal Agent Microdochium nivale Develops in periods of snow cover or cold rain Needs high moisture Occurs from November to April (32-60 degrees) Can occur under leafs or debris that were not removed before winter

4. Environmental/ Mangement Controls Keep mowing grass and raking leaves in the fall until all leaves are gone and grass has stopped growing Don’t allow snow to get compacted Aerify often in areas that are prone Prune trees and shrubs to allow better air flow Develop better surface drainage Don’t apply nitrogen if cold weather is coming

5. Life Cycle After a period of mycelia growth when the snow melts, Typhula fungi produce small round or flattened structures called sclerotia. The sclerotia are embedded or attached to the leaves and crowns of diseased plants. They lie dormant during the following summer. The sclerotia germinate in cold, wet weather, usually after snow melt, and produce pinkish/ grayish spore bearing sporocarps that infect all tissues of the grass plant. This starts the disease.

6. Symptoms/Identification Symptoms appear as brown or straw colored circular patches/spots ranging from 3 to 12 inches in diameter The foliar symptoms are blighting of the leaves and the leaves can turn tan, brown, white or even a pinkish color Circles can coalesce and become large masses of dead and matted grass

7. Best Controls Rake matted areas so it can dry faster Lightly fertilize damaged area Apply protective fungicides Removing infected area and sodding or seeding is also an option

8. Why I chose pink snow mold? I chose this disease because I thought it very interesting and I thought I might come across it sometime in my career. I wanted to know the causes of it and how to treat it.

9. The effect of age and cold hardening on resistance to pink snow mould in perennial ryegrass A purpose of this experiment was to see if the age and the cold hardiness of a plant have an effect on pink snow mold in perennial ryegrass. Another reason for this experiment was to see if the age and cold hardiness of perennial ryegrass plants were different in their ability to express pathogenesis-related genes during incubation.

10. The effect of age and cold hardening on resistance to pink snow mould in perennial ryegrass There were three cultivars of perennial ryegrass in the experiment (cv. Riikka, cv. Viris, cv. Norlea) Perennial ryegrass seeds were germinated at 15-25 degrees Celsius in a greenhouse and then transplanted three pots, one pot per cultivar. ( 10 cm pots, 9 seeds per pot) After two weeks they were put in growth cambers in a sand and peat mixture Nutrient solution were given weekly during cultivation Plants were inoculated with snow mould 4-8 weeks after sowing Unhardened plants were cut to 10 cm two weeks before inoculation. Hardened plants were grown at 2 degrees Celsius for the last two weeks before inoculation. Material above soil was harvested from the pots of the three cultivars on the day of inoculation

11. The effect of age and cold hardening on resistance to pink snow mould in perennial ryegrass Perennial ryegrass resistances to snow mould increased with age of the plant at the time of inoculation. Hardened plants ( with two or more extra weeks of hardening) have a higher resistance to pink snow mould than unhardened plants do, but both hardened and unhardened plants that were sown on the same day didn’t show differences in resistance to snow mould.

12. Exponential growth of snow moulds at sub zero temperatures: an explanation for high beneath snow respiration rates and Q10 values The purpose of this experiment was to see if snow mold could grow exponentially in very cold weather conditions. Another purpose of this experiment was to see how much CO2 respiration took place in soil that is covered by snow.

13. Exponential growth of snow moulds at sub zero temperatures: an explanation for high beneath snow respiration rates and Q10 values The study was done near Boulder, Colorado. Fungal mats were used to measure how much snow mould grew at different temperatures ranging from -3°C to 3.78°C Each experiment was conducted three times in low temperature incubators. The results from these test were then taken and compared to the CO2 production that happened underneath the snow. This was done through a series of equations that showed the linear regression of the two compared to each other over time.

14. Exponential growth of snow moulds at sub zero temperatures: an explanation for high beneath snow respiration rates and Q10 values All of the fungi mats could grow snow mould at the lowest temperature.CO2 respiration also occurred in all the mats The results concluded that small changes of temperature in the snow has large affects of the growth of snow moulds and the respiration rate of CO2. It also concluded that lower temperatures (-3° to -.3°) contribute to more snow mould growth and in turn contribute to higher respiration rates.

15. Sources: http://www.f1point4.com/f1point4/images/snow_grass_1.jpg http://www.colostate.edu/Dept/CoopExt/4dmg/Pests/Diseases/snowmold.htm http://www.tdl.wisc.edu/pinksm.php http://lawncare.about.com/od/turfgrasspests/a/snow_mold.htm http://www.turffiles.ncsu.edu/Diseases/Pink_Snow_Mold.aspx http://archive.lib.msu.edu/tic/grnma/article/1988jan41.pdf http://www.hgca.com/minisite_manager.output/3677/3677/Cereal%20Disease%20Encyclopedia/Diseases/Snow%20Mould%20(Pink%20Snow%20Mould).mspx?minisiteId=26 http://web.ebscohost.com.libproxy.eku.edu/ehost/pdfviewer/pdfviewer?sid=6575fd18-8c0e-499e-9553-d5acea3a2a1e%40sessionmgr12&vid=5&hid=107 http://web.ebscohost.com.libproxy.eku.edu/ehost/pdfviewer/pdfviewer?vid=12&hid=15&sid=6575fd18-8c0e-499e-9553-d5acea3a2a1e%40sessionmgr12