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Disease suppression without fungicides


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1st of 3 presentations to the Czech Greenkeepers School of Education earlier this week..

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Disease suppression without fungicides

  1. 1. How did I get into turfgrass?
  2. 2. • Concentrate on Anthracnose and Microdochium nivale • Disease pyramid to target how we can reduce disease • Pathogen infection process and plant defences • Defence priming and enhancement • Cultural practices • Nutritional Disease Management Trials showing disease reduction and mode of suppression Todays talk Disease suppression with limited fungicides
  3. 3. Traditional and alternative ways to reduce disease Nutrient inputs Nitrogen Ferrous sulphate Silica Sulphur Biological controls Compost teas Antagonistic organisms Defence activators Civitas Salicylic acid Phosphite (of course) Cultural controls Rolling Topdressing Irrigation Mowing heights Factors which contribute to disease levels and how we can influence these
  4. 4. Disease - the malfunctioning of host cells and tissues that results from their continuous irritation by a pathogenic agent and leads to the development of symptoms (Agrios, 1988). What is a disease? Problems caused by a pathogen on amenity turfgrasses Visual quality Playing quality
  5. 5. Some common cool season pathogens
  6. 6. Available Fungicides: • Azoxystrobin • Pyraclostrobin • Difenoconazole • Fludioxonil • Trifloxystrobin • Tebuconazole • Fluopyram Fungicides withdrawn in last 5 years: • Carbendazim • Chlorothalonil • Iprodione • Propiconazole Alternative means to suppress disease are urgently needed
  7. 7. Indicates a problem with turf•Reduce stress •Help plants to respond to stress
  8. 8. Anthracnose - Infection process
  9. 9. mold Uk and Ireland it’s the most common pathogen in turfgrass Its also the most economically important winter disease of turfgrass in the northern and alpine regions of Europe, US and Canada Ascomycete fungus - Fusarium patch or Pink snow-mould What is Microdochium nivale?
  10. 10. Host – All cool season turfgrass species Conditions Persistent humidity, moist surface, high N + pH
  11. 11. Microdochium active on turfgrass
  12. 12. Using pot samples and infected greens
  13. 13. • M. nivale isolates were originally identified on the basis of colony characteristics, conidial morphology and on re-infection symptoms • These identifications were later confirmed following DNA extractions in TrisEDTA buffer and testing by polymerase chain reaction (PCR), using primers, EFniv-F/EF-Mic-R (Glynn et al., 2005)
  14. 14. M. nivale hyphal growth on infected turfgrass leaves following emergence from the soil/thatch interface
  15. 15. Hyphae enters plant via stomata
  16. 16. L.E. Jewell and T. Hsiang, 2012, School of Environmental Sciences, University of Guelph, Guelph, 10 Ontario, N1G 2W1, Canada.
  17. 17. • Hyphae/conidia in the soil/thatch are the main source of inoculum • Environmental conditions allow infection to commence • Mycelium grows from the base of the plant • Infection by means of stomatal penetration/appressoria formation • Infects the plant extracting nutrients • Then emerges from plant producing conidia which are the means of propagation and dispersal • Infected plants respond with chemical defences Host recognition
  18. 18. Can these defences be stimulated or enhanced? Defence activators Treatments to control diseases by priming the expression of plant defences • Civitas • Chitin • Salicylic acid • Harpin • Phosphite
  19. 19. Environmental factors • Dew removal • Air movement and light quality • Reduce stress on turf Plant factors • Less susceptible species and cultivars • Balanced nutrient inputs • Nutritional IPM -Use of compounds to reduce disease incidence Cultural practices • Lightweight rolling • Sand topdressing • Mowing and irrigation practices
  20. 20. Effects of topdressing on disease incidence Light, frequent topdressing buries and protects the crowns and sheaths. Note depth of crowns in middle and right compared to left with no topdressing Photo by J. Inguagiato
  21. 21. Manage excess moisture, running irrigation at 60 to 80 percent evapotranspiration rate to prevent moisture stress to already shallow-rooted Poa annua
  22. 22. Biological controls? • Antagonistic fungi and bacteria • Establishment and persistence • Activity against isolates • Composts • Increase in fertility • Increase in antagonistic fungi • Compost tea? • Trichoderma spp.
  23. 23. • The nutritional status of the sward can have a direct effect on disease incidence • A nutritional balance is the goal • Excessively high and low fertility contributes to turfgrass disease pressure • ‘Nutritional IPM’ • Minimum Levels for Sustainable Nutrition (MLSN) PACE TURF and Asian Turfgrass Centre Plant nutrition
  24. 24. Nitrogen was applied at 4.9 kg N ha−1 every 7 or 14 dàys • Àmmonium sulfate • Ammonium nitrate • Urea • Calcium nitrate • Potassium nitrate Both N frequency and N source affected disease N applied every 7 days reduced disease compared with N applied at the same rate every 14 days. Potassium nitrate provided the greatest reduction in disease severity over the 3-yr study Ammonium sulfate treatments resulted in the greatest disease severity. This study has shown that anthracnose severity on ABG putting green turf is influenced by N source, and that low-rate applications of potassium nitrate every 7 d were most effective at reducing disease severity
  25. 25. What about potassium?
  26. 26. Potassium v Anthracnose
  27. 27. Dr Doug Soldat, University of Wisconsin-Madison
  28. 28. The treatments included five different levels of biweekly liquid potassium sulfate at rates ranging from zero to 30 kg/ha of K. In the fifth year, significantly lower turf quality was observed on the two no K treatments. However, these low K treatments had significantly less Microdochium patch than the treatments receiving K applications during the past three winters. Few, if any, differences in turf colour, quality, or growth rate among the treatments were observed during the first four years of the study. Mehlich-3 K was near 20 mg/kg in the no K treatments and ranged from 25-50 mg/kg in the treatments receiving K.
  29. 29. Use of Iron to reduce disease
  30. 30. Clint Mattox, MSc: Managing Microdochium Patch using non-traditional fungicides on Annual bluegrass putting greens Treatments Urea (46N) (0.0, 4.88, and 9.76 kg N ha−1) FeSO4 (11.5% S 20.1% Fe) 0.0, 12.21, 24.41, 48.82 and 97.65 Kg product per Ha-1 Bi-weekly applications in 800L/Ha water
  31. 31. Trial conducted at STRI in UK October – December 2015 Randomised complete block design with 14 treatments Trial area of indigenous sandy loam soil Poa annua/bentgrass sward Site managed to have high disease pressure risk Common Microdochium outbreaks Effect Fe Curatively
  32. 32. Fe studies
  33. 33. Manganese serves as activator for several enzymes of the shikimic acid pathway that leads to the synthesis of aromatic amino acids. These are the starting products for the synthesis of phenolic acids and alcohols that are produced in response to attack by pathogenic fungi and constitute a major disease defence mechanism
  34. 34. Silica (Silicon) for disease suppression
  35. 35. Silica for disease suppression
  36. 36. Calcium is important for strong cell walls, abiotic stress tolerance, and biotic pest resistance. Calcium is relatively immobile once absorbed by plants, therefore foliar calcium applications ensure adequate concentrations in leaf tissue Elevation in calcium concentration in plant cells is an essential early event during plant defence responses
  37. 37. Sulphur More recently in Oregon State University, sulphur significantly reduced the number of Microdochium patch infection centres and reduced the number of fungicide applications required Another compound for disease suppression is the use of sulphur or sulphur containing products such as iron or ammonium sulfate to decrease pressure from fungal pathogens. Sulphur has been used in agriculture for pest control for well over 2000 years and has been shown to suppress Microdochium patch on bentgrass putting greens when applied annually at 224 Kg ha-‐1 (Brauen et al., 1975).
  38. 38. Phosphite Form of Phosphorus (P) a major nutrient of plant growth Taken up as Phosphate - Phosphoric acid (H3PO4) Phosphite - Phosphorous acid (H3PO3) Phosphite not metabolised in plants
  39. 39. Joshua Cook; Peter Landschoot, Ph.D.; and Max Schlossberg, Ph.D.
  40. 40. In vitro mycelial growth rate of Microdochium majus measured on PDA amended with potassium phosphite solution – Hofgaard et al 2010
  41. 41. Royal Curragh field trials
  42. 42. Figure 3-2 Monthly disease incidence, P. annua, January 2011 (year 1). Treatment effect on percent M. nivale incidence on trial plots (n=5), of P. annua, during the month of greatest disease incidence in year 1 of the trial, January 2011.
  43. 43. Figure 3-3 Monthly disease incidence, A. canina, December 2010 (year 1). Treatment effect on percent M. nivale incidence on trial plots greatest disease incidence in year 1 of the trial, December 2010.
  44. 44. Figure 3-7 Monthly disease incidence, A. stolonifera, November 2011 (Year 2). Treatment effect on percent M. nivale incidence on trial plots (n=5), of A. stolonifera during the month of greatest disease incidence in year 2 of the trial, November 2011.
  45. 45. Phosphite Fungicide + Phosphite
  46. 46. We assessed the effect of phosphite treatment on turfgrass quality Turfgrass quality P. annua, A. canina and A. stolonifera, September 2011 to March 2012
  47. 47. Turfgrass quality mean values over four years 2010 to 2014
  48. 48. Poa annua plots – October 2011 CONTROL PHOSPHITE
  49. 49. Agrostis canina plots – January 2012
  50. 50. Poa annua plots – January 2011
  51. 51. Poa annua plot 5 – Phosphite
  52. 52. Poa annua plot 16 - Control
  53. 53. Agrostis stolonifera plot 7 – Phosphite
  54. 54. Agrostis canina plot 9 – Phosphite
  55. 55. Agrostis canina canina plots – January 2011 CONTROL PHOSPHITE
  56. 56. Poa annua plots – October 2011 CONTROL PHOSPHITE
  57. 57. Control plants – January 2008
  58. 58. Phosphite treated plants – January 2008
  59. 59. Sequential applications of phosphite significantly reduced Microdochium nivale incidence The addition of phosphite to fungicides significantly enhanced disease suppression Significant improvement in turfgrass quality
  60. 60. • Inhibits pathogen Direct • Stimulates plants defences Indirect Combination of both
  61. 61. Microdochium propagated from infected turfgrass Grown on and used for in vitro study To assess inhibition of mycelial growth
  62. 62. Figure 2-5 Percent inhibition of M. nivale mycelial growth on H3PO3, KH2PO3, H3PO4, KH2PO4 and KOH amended PDA.
  63. 63. Mycelial Growth on Amended PDA - 4 days p.i.
  64. 64. Effect on hyphal morphology Unamended 75µg/ml Phosphite
  65. 65. • Inhibits mycelial growth and conidial germination • Disrupts hyphal morphology • Causes release of stress metabolites In the plant – • Slows the growth of the pathogen • Allows for faster recognition of the pathogen by the plant Primes the plant defences prior to infection
  66. 66. Latest Research projects Field trials: Anthracnose suppression 2018 Microdochium suppression 2018/19 We used a range of products containing Phosphite, Calcium, Sulphur, Manganese, Zinc, Copper, Salicylic acid and Fe
  67. 67. Anthracnose trial - 2018 Treatments Rate oz/1000ft2 Application timing (1) Untreated Control 14 days (2) Phosphite 30 3 14 days (3) 29-0-0 4 14 days Healthy Start 4 Phosphite30 2 Impulse 4 Hydration A 0.7 (4) BannerMaxx 1 14 days
  68. 68. Plant Food 29-0-0 Includes Calcium, Sulphur, Copper, Fe, Manganese and Zinc, all important for disease suppression Healthy Start 8-27-5 NPK plus Polyphosphite Impulse and Hydration A increased calcium availability and provided Salicylic acid which stimulates Systemic Acquired Resistance The combination of products reduced Anthracnose incidence by providing adequate and balanced nutrition • Less stress= less Anthracnose • Provided elements shown to reduce disease incidence • Primed and enhanced the plants natural defences Phosphite 30 Primed and enhanced defence responses
  69. 69. Latest Microdochium suppression trial Ran from September 2018 to March 2019 Assessing product combinations containing Phosphite, Calcium, Sulphur, Silica, Salicylic acid and Fe Comparisons to untreated controls and fungicide treated plots
  70. 70. Treatments Rate oz/1000ft2 Application timing (1) Untreated Control 0 14 days (2) Phosphite 30 3 14 days (3) Healthy Start 4 14 days Phosphite 30 2 Impulse 4 Hydration A 0.7 (4) Instrata 3 14 days Microdochium nivale trial 2018/2019
  71. 71. Microdochium nivale trial 2018/2019 Treatments Rate oz/1000ft2 Application timing (1) Untreated Control 0 14 days (2) Phosphite 30 3 14 days (3) Healthy Start 4 14 days Phosphite 30 3 Impulse 4 Hydration A 0.7 Iron 4.5% EDTA Chelate 2 (4) BannerMaxx 3 14 days
  72. 72. Phosphite, Calcium, Salicylic acid
  73. 73. Phosphite, Calcium, Salicylic acid Fe
  74. 74. Phosphite 30 Suppressed M. nivale by enhancing defence responses Phosphite 30, Healthy Start, Impulse and Hydration A • Ensured adequate nutrition • Supplied Calcium and Phosphite for defence responses • Salicylic acid for Systemic resistance Inclusion of PlantFoodCO Fe further increased disease suppression
  75. 75. Microdochium nivale Ensure all environmental pressures are reduced as much as possible. • Dew removal. • Timely use of aeration operations and topdressing. • Incorporate rolling more into the program. • All factors which reduce the microclimate conducive to Microdochium development. • Nutritional program to include compounds such as phosphite, sulphur, salicylic acid, seaweed as part of balanced sequentially applied nutritional treatments. Anthracnose Indicates a stress related problem with the turfgrass. • Use cultural management procedures to reduce disease pressure, relieve compaction. • Light topdressing, increased heights of cut, rolling. • Regular low inputs of N. • Nutrient program which includes phosphite, calcium, sulphur, silica, salicylic acid and copper will combine to reduce disease incidence. • Azoxystrobin fungicide as a preventive program.
  76. 76. Thanks for listening! Questions?