Slides from my seminar at BTME 2018 at Harrogate

1. Centre for Research in Biosciences
Turfgrass disease
Alternative means of control

2. Centre for Research in Biosciences
Supplement to fungicide use
Methods to help reduce
disease

3. Greenkeeper since 1980’s
Course manager 1993

4. How did I get into turfgrass?

7. BSc in Turfgrass science – Myerscough college
Final year research project-
The Effects of Phosphite on the Growth
and Disease Susceptibility of Agrostis
stolonifera

8. Centre for Research in Biosciences
PhD in Plant Pathology
Suppression of Microdochium nivale by
Phosphite in Cool-season Turfgrass

9. Todays talk

10. Any slides or references made to products or
suppliers are based on robust, replicated trial data
Factors which contribute to disease levels and
how we can influence these
Two of the most common Pathogens and their
infection processes
• Nutrient inputs
• Biological controls
• Cultural controls
• Defence activators

11. 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

12. Some common cool season pathogens
Anthracnose
Microdochium patch

13. Factors for disease incidence
Turf managers need to focus
on factors we can successfully
influence

14. 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.
Weather patterns and environmental effects are vital
DewSmart was applied every 14 days at 10 L / ha in 250 L water. Application was made to a dry leaf where possible

15. Plant factors
• Breeding for resistance
• Cultivar selection
• Species conversion
• Nutrition
Nutritional IPM
Use of various compounds to
reduce disease

17. Time factor
• Plant defences
Enhancement of natural defence
mechanisms
Priming defence prior to infection
Slow the infection process

18. Pathogen factor
Anthracnose
Microdochium patch
The two most common we encounter in
UK and Ireland

19. Anthracnose –Colletotrichum cereale
Symptoms Foliar blight-
Mostly mid-summer
leaves and shoot discolour, similar appearance to
drought stress
attacks the leaves and stems

20. Indicates a problem with turf
• Correct any compacted areas
• Minimise thatch
• Adequate fertiliser (N)
• Relieve any areas of stress

21. Anthracnose - Colletotrichum cereale, occurs when
plants are stressed.
Spores are produced in acervuli
Under favourable conditions spores germinate
And produce appressoria from which it penetrates
the plant tissues.
Infested plants can display acervuli with distinctive
black spines, which can produce numerous conidia.
These can be dispersed by splashing water or
tracked by mowing equipment.
These spores then germinate and cause new
infections on other plants.

22. Fusarium patch - Microdochium nivale
Host – All cool season turfgrass species
• Conditions
Persistent humidity, moist surface, high N + pH
• Symptoms
Orange / brown spots initially that enlarge and coalesce.
• Survival and spread
Survives on infected plants and thatch
Spread by conidia in water + wind, infected debris
Infects through stomata and wounds

24. Infection processes
Fluorescence
microscopy and stains
Microdochium nivale
We studied the
infection process using
pot samples and
infected greens

25. Inoculum in the soil
conidia or mycelium
Infection first in the
crown and sheath
area
Moves to the leaf and
enters plant through
stomata
The plant recognises
the pathogen, this
leads to induction of
defence responses
Then exits and
produces conidia

26. 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

27. Lets look at some traditional and alternative ways
to reduce disease
Nutrient inputs
Nitrogen
Ferrous sulphate
Silica
Sulphur
Potassium
Biological controls
Compost teas
Antagonistic organisms
Defence activators
Civitas
Harpin
Chitin
Phosphite (of course)
Cultural controls
Rolling
Topdressing
Irrigation
Mowing heights

28. • 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

30. Use of Iron to reduce disease

31. Clint Mattox, MSc: Managing Microdochium Patch using non-traditional
fungicides on Annual bluegrass putting greens

32. 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

33. Methodology
Trial conducted at STRI. October – December 2015
Randomised complete block design with 14 treatments
Trial area of indigenous sandy loam soil
Poa annua/Browntop bentgrass sward
Site managed to have high disease pressure risk
Common Microdochium outbreaks

34. Effect Iron Programme
Control Plot Effect Fe Preventatively
Applying Iron curatively significantly reduced the incidence of Microdochium.
Preventative applications did not have any significant effect.
Timing of curative applications is critical to achieve best results.
Effect Fe Curatively
Dr Andy Owen, International Technical
Manager

35. Fe studies

36. Silica for disease suppression

38. 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).

39. Factors includes sulphur rates (0, 3 and 6 lbs of S per 1,000 ft2 annually) and calcium source
(calcium carbonate, calcium sulfate and calcium phosphate all applied at 12 lbs of product per
1,000 ft2 annually and compared to untreated control).

40. What about potassium?

41. What about potassium?
Dr Doug Soldat, University of Wisconsin-Madison

42. 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.

43. Potassium v Anthracnose

44. Biological controls?
• Antagonistic fungi and bacteria
– establishment and persistence
– activity against isolates
– pesticide use
• Trichoderma spp.
• Composts?
– Increase in fertility
– Increase in antagonistic fungi

48. Jason Haines, Superintendent at Pender Harbour Golf Club,
BC, Canada
Effect of rolling on disease incidence

51. 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

53. Turfgrass defence responses

54. Defence activators
• Civitas
• Harpin
• Phosphite
Can these defences be stimulated or enhanced?
Treatments to control diseases by priming the
expression of plant defences

56. Harpin
Harpin is a plant elicitor, it
binds to receptors on the
plant leaf and triggers
physiological processes
within the plant
‘Systemic acquired
resistance’
SAR

57. Phosphite
Form of Phosphorus (P) a major nutrient of plant growth
Taken up as Phosphate - Phosphoric acid (H3PO4)
Phosphite - Phosphorous acid (H3PO3)

58. 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

60. Phosphite treated plants – January 2008

61. Control plants – January 2008

62. Sequential applications of phosphite
significantly reduced Microdochium nivale
incidence
The addition of phosphite to fungicides
significantly enhanced disease suppression

64. Mycelial Growth on Amended PDA - 4 days p.i.

65. Effect on hyphal morphology
Unamended 75µg/ml Phosphite

66. • Measured using reagent and spectroscopy
• Important response to stress and pathogen
challenge
• Visualised using fluorescent microscopy
Turfgrass defence responses
Phenolic compounds

68. Figure 5-24 TPC as GAE mg/g dw, in turfgrass tissues sampled from greenhouse plants following six,
monthly applications of SDW (control), Phosphate (Pi) and Phosphite (Phi). Bars indicate 95%
confidence limits, letters indicate significant differences determined by Post hoc comparisons using
Bonferroni correction at p < 0.05, n=10.
Total phenolic content in turfgrasses following sequential
treatments of phosphate and phosphite

69. Accumulation of phenolic compounds in infected bentgrass leaves
Phenolic compounds (yellow) accumulated close to the penetration sites.
Phenolic compounds are a component of initial defence responses
Phosphite treatment led to enhanced responses and increased accumulations

70. 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

71. Take home points
Biological controls
• Compost/compost teas
• Antagonistic organisms
• Healthy well aerated growth media
Cultural practices
• Lightweight rolling
• Sand topdressing
• Mowing and irrigation practices
Defence activators
• Civitas
• Harpin
• Phosphite

72. 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

73. Follow updates on Twitter -
@J_J_Dempsey