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Alternative means of disease control saltex
- 3. Centre for Research in Biosciences PhD in Plant Pathology Suppression of Microdochium nivale by Phosphite in Cool-season Turfgrass
- 4. Traditional and alternative ways to reduce disease Nutrient inputs Defence activators Cultural controls Factors which contribute to disease levels and how we can influence these Todays talk Methods to help reduce disease
- 5. Some common cool season pathogens Anthracnose Microdochium patch
- 6. Factors for disease incidence Turf managers need to focus on factors we can successfully influence
- 7. Pathogen factor Anthracnose Microdochium patch The two most common we encounter in UK and Ireland
- 8. Indicates a problem with turf•Reduce stress •Help plant to respond to stress Anthracnose –Colletotrichum cereale
- 9. Host – All cool season turfgrass species Conditions Persistent humidity, moist surface, high N + pH Fusarium patch - Microdochium nivale
- 10. Infection processes Fluorescence microscopy and stains Microdochium nivale We studied the infection process using pot samples and infected greens
- 11. Infection processes • 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 appressoria formation for Anthracnose and stomatal penetration for Microdochium • 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
- 12. Environmental factors • Surface moisture • Temperatures • Humidity • Poor air movement • Light quality The environment is a key factor for disease development Turfgrass and pathogens are always present. • Surface moisture
- 13. DewSmart was applied every 14 days at 10 L / ha in 250 L water
- 14. What about cultural controls? • Rolling • Topdressing • Irrigation • Mowing heights
- 15. 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
- 16. Manage excess moisture, running irrigation at 60 to 80 percent evapotranspiration rate to prevent moisture stress to already shallow-rooted Poa annua
- 18. • Dew reduction • Rolling • Topdressing • Irrigation • Height of cut
- 19. Plant factors • Breeding for resistance • Cultivar selection • Species conversion • Nutrition Nutritional IPM Use of various compounds to reduce disease
- 22. Use of Iron to reduce disease
- 23. Silica for disease suppression
- 25. 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
- 28. Time factor • Plant defences Enhancement of natural defence mechanisms Priming defence prior to infection Slow the infection process
- 29. Defence activators • Civitas • Harpin • Phosphite Can these defences be stimulated or enhanced? Treatments to control diseases by priming the expression of plant defences
- 31. Harpin: "Treating plants with the Harpin protein signals the plant to turn on its natural defence systems" Steven V. Beer, Cornell professor of plant pathology and one of the protein's discoverers in 1991.
- 32. 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
- 33. Trials ran from September to March each year 2010 to 2014 Phosphite applied alone or in combinations with fungicides and biostimulants Agrostis canina canina Agrostis stolonifera Poa annua Disease incidence assessed monthly Turf quality was also assessed Phosphite v Microdochium Royal Curragh golf course field trials
- 36. Summer 2018 research Control PolyPhosphite 30 29-0-0, Healthy Start, PolyPhosphite 30, Impulse, Hydration A BannerMaxx 13/08/2018 18 9 3.5 2.75 28/08/2018 34.75 11 4.5 5.5 04/09/2018 20.25 7 3.5 3.5 0 5 10 15 20 25 30 35 40 45 50 %Anthracnose Percent Anthracnose levels in Royal Curragh trial plots
- 37. Mycelial Growth on Amended PDA - 4 days p.i.
- 38. Total phenolic compounds 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Control Infected Control Infected Control Infected 2012 2013 2014 GAEmg/g P. annua Turfgrass defence responses
- 39. Total phenolic compounds in turfgrass tissues sampled from greenhouse plants following six, monthly applications of SDW (control), phosphate and phosphite 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 control Phosphate Phosphite GAEmg/gDW P.annua 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 control Phosphate Phosphite GAEmg/gDW A. stolonifera
- 40. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 0 dpi 1 dpi 2 dpi 3 dpi 4 dpi 5 dpi 6 dpi 7 dpi 8 dpi 9 dpi 10 dpi GAEmg/gdw P. annua Control Pi Phi (6 apps) Total phenolic compounds in M. nivale infected P. annua over 10 dpi following treatment with SDW (control), phosphate and phosphite (6 apps)
- 41. Hydrogen peroxide concentrations as μmol H2O2/g fw Sampled from infected turfgrass over 10 days post inoculation Hydrogen peroxide generation 0 to 10 dpi 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 0 dpi 2 dpi 4 dpi 6 dpi 8 dpi 10 dpi μmolH2O2/gfw Agrostis stolonifera
- 42. 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 0 dpi 2 dpi 4 dpi 6 dpi 8 dpi 10 dpi μmolH2O2/gfw A. stolonifera Control Pi Phi ( 6 apps) H2O2 concentrations in M. nivale infected greenhouse turfgrass tissues H2O2 concentrations control, phosphate and phosphite treated tissues of A.stolonifera greenhouse plants over 10 days post inoculation
- 43. We need to focus on the factors we can successfully influence to reduce disease Take home points Environmental factors • Dew removal • Air movement and light quality • Rootzone and rhizosphere • Reduce stress on turf Plant factors • Less susceptible species and cultivars • Balanced nutrient inputs • Use of compounds to reduce disease incidence
- 44. Take home points Cultural practices • Lightweight rolling • Sand topdressing • Irrigation inputs • Mowing practices Defence activators • Civitas • Harpin • Phosphite
- 45. Take home points None of these alone will fully eliminate disease! Hopefully you will be able to incorporate some into your maintenance programmes They will help to reduce disease incidence and help reduce reliance on fungicides Some will also enhance your fungicide programmes
- 46. Follow updates on Twitter - @J_J_Dempsey
Editor's Notes
- I followed that be beginning my PhD in Plant Pathology at UWE Bristol Does phosphite reduce M. nivale infection? Means of suppression Effects on growth and quality
- We looked at the M. nivale infection process Infected field and greenhouse samples were used to study the infection process and defence responses. using a series of microscopic analyses techniques. Light and fluorescence microscopy was used for the visualization of M. nivale infection structures using fluorescent indicator dyes. Stained fragments of leaves, leaf sheaths, crowns, Thatch and rootzone samples
- So What is Phosphite? Phosphorus – a major plant nutrient, its required for numerous processes in all plants, it’s usually taken in in the form of Phosphate which has a chemical formulation of H3PO4. Phosphite is very similar to Phosphate –its formulation is H3PO3 – there’s only one molecule of Oxygen in the difference, however where as phosphate is vital for numerous metabolic processes in the plant, Phosphite has no such discernible functions. There’s a lot of conjecture regarding the use of phosphite and it’s often marketed as a form of nutritional input but really the evidence is that it does not supply P in a form usable by plants. There’s research going back to the 1950’s showing this, it’s down to the actual shape of the ions, phosphate to be utilised in the plant, binds with a number of enzymes, which help to incorporate it into the plant, these fit together like jigsaw pieces and the shape of the phosphite ion does not fit with this.
- We carried out field trials for 4 seasons Sites at the Royal Curragh Golf Club composed of Poa annua L., Agrostis canina L. ssp. Canina, Agrostis stolonifera L., All treatments were completely randomised with five replications, comprising of sequential applications, applied as a foliar spray. All trial plots were assessed for M. nivale incidence monthly,, from September to March each year Assessment of turf quality were also determined monthly, this was assessed visually and marked on a scale of 1 – 10.
- Mean values of M. nivale incidence on trial plots over 4 years.
- Research from Rutgers University, 2008 on the use of phosphite in the preventative control of Anthracnose
- This series of pictures highlights the affects on M. nivale mycelia of incorporating phosphite into the growth media.
- H2O2 concentrations as μmol H2O2/g fw, in SDW (control), phosphate (Pi) phosphite (Phi) (1 app) and phosphite (Phi) (6 apps) treated tissues of M. nivale infected P.annua and A. stolonifera greenhouse plants over 10 days post inoculation. Bars indicate 95% confidence limits, letters indicate significant differences at each time period determined by Post hoc comparisons using Bonferroni correction at p < 0.05, n=10.
- That’s it! Hopefully you enjoyed the talk and found it of some interest, if you want to keep in touch with the work you can find me rambling on about it on Twitter @J_J_Dempsey or at some publications below. PUBLICATIONS: Dempsey, J. Wilson, I. Spencer-Philips, PTN and Arnold, D. (2014). Phosphite Mediated Inhibition of Microdochium nivale. Proceedings of the 4th European Turfgrass Society Conference, July 2014, Osnabrueck, Germany. European Turfgrass Society. Dempsey, J. Wilson, I. Spencer-Philips, PTN and Arnold, D. (2014). Phosphite mediated inhibition of Microdochium nivale in Turfgrass. Proceedings of the Irish Plant Scientists Association meeting, Cork, Ireland, April 2014. Dempsey, J. Wilson, I. Spencer-Philips, PTN and Arnold, D. (2014). Phosphite Mediated Inhibition of the Ascomycete pathogens Microdochium nivale and M. majus in the Gramineae. Proceedings of Crop Protection in Northern Britain, Dundee, February 2014. Dempsey, J. (2013). “Phosphite –what’s all the Fuzz about?” Pitchcare magazine, February/March 2013: 106-109. Print. Dempsey, J. (2012). “Suppression of Fusarium patch by phosphite in cool -season turfgrasses.” Greenside magazine, December 2012: 50-53. Print. Dempsey, J. Wilson, I. Spencer-Philips, PTN and Arnold, D. (2012). Assimilation of Phosphite by Agrostis stolonifera L. and its In Vitro Effect on Microdochium nivale. Proceedings of the 3rd European Turfgrass Society Conference, June 2012, Kristiansand, Norway. European Turfgrass Society Dempsey, J. Wilson, I. Spencer-Philips, PTN and Arnold, D. (2012). Suppression of Microdochium nivale by potassium phosphite in cool-season turfgrasses. Acta Agriculturae Scandinavica, Section B - Soil & Plant Science. 62, (1): 70-78. Dempsey, J and Owen, A. (2010). The Effect of Phosphite Treatments on the Growth and Disease Susceptibility of Agrostis stolonifera L. Proceedings of the 2nd European Turfgrass Society Conference, April 2010, Angers, France European Turfgrass Society, 67-69.