Eastern North Carolina Turfgrass Association Wayne Community College February 17, 2011

1. ENCTA - Turf Diseases

2. Was 2010 Hot?
departure from normal HIGH temperature
departure from normal LOW temperature
30
22.5
Departure from Normal (F)
15
7.5
0
-7.5
-15
-22.5
May June July August Sept Oct

4. Total Samples
In-State
Out-of-State
502
377
251
126
0
2005 2006 2007 2008 2009 2010

5. 2009-10 Bentgrass Samples By Month
2009
2010
120
90
60
30
0
n
b
ar
r
ay
n
l
g
p
ct
ov
c
Ju
Ap
De
Ja
Ju
Au
Fe
Se
O
M
M
N

6. Who developed your fungicide program?
Manufacturer or Distributor
University Researcher
Colleague
I developed it.
I don’t know.
0 3 6 9 12 15
# of respondents
Survey conducted at NC Turf Conference, December 14 2010

7. How often do you make changes to your program during
the season?
frequently
sometimes
never
0 3 6 9 12 15
# of respondents
Survey conducted at NC Turf Conference, December 14 2010

8. What factors do you consider when making changes?
disease outbreaks
online alerts
diagnostic lab results
reports from colleagues
reports from sales reps
weather conditions
0 3 6 9 12 15
# of respondents
Survey conducted at NC Turf Conference, December 14 2010

9. What sources of information do you use when selecting
fungicides?
Manufacturer or Distributor
University Personnel
Colleagues
Pest Control for Professional Turf Managers
Disease Management Utility on TurfFiles
Disease Profiles on TurfFiles
product labels
0 3 6 9 12 15
# of respondents
Survey conducted at NC Turf Conference, December 14 2010

10. Which of these is your primary source of information when
selecting fungicides?
Manufacturer or Distributor
University Personnel
Colleagues
Pest Control for Professional Turf Managers
Disease Management Utility on TurfFiles
Disease Profiles on TurfFiles
product labels
0 3 6 9 12 15
# of respondents
Survey conducted at NC Turf Conference, December 14 2010

11. Did you have any disease outbreaks in 2010?
algae
anthracnose
bacterial wilt
brown patch
copper spot
dollar spot
fairy ring
Pythium blight
Pythium root dysfunction
Pythium root rot
red leaf spot
slime mold
pink snow mold
summer patch
yellow patch
none
0 3 6 9 12 15
# of respondents
Survey conducted at NC Turf Conference, December 14 2010

12. Fungicide Selection Tool

13. Bacterial Wilt: Is it Real?

14. History of Bacterial Diseases
• severe epidemic in Midwestern US on ‘Toronto’ creeping bentgrass in
1970’s caused by Xanthomonas transluscens
• X. transluscens continues to be an occasional problem on Poa annua
greens in the northern US
• efforts to develop this into a bio-herbicide failed due to lack of efficacy
in absence of severe stress
• 2009 - report of a bacterial disease caused by Acidovorax spp. in
Charlotte, NC

15. Quail Hollow Country Club, Charlotte, NC

16. Quail Hollow Country Club, Charlotte, NC

17. Quail Hollow Country Club, Charlotte, NC

18. Koch’s Postulates: Establishing a Cause-Effect
Relationship
1. Suspected pathogen must be constantly
associated with specific symptoms over
time and space
2. Suspected pathogen must be isolated
into pure culture and identified
3. Same symptoms are reproduced when
suspected pathogen is introduced to
healthy plants
4. Suspected pathogen re-isolated from
symptomatic plants and identified

19. Bacterial Disease Timeline
June 2009 - samples from Quail Hollow Country Club submitted to
Michigan State University for disease diagnosis
October 1, 2009 - Michigan State reported to Quail Hollow that the
problem was a bacterial disease caused by a species of Acidovorax
October 2, 2009 - attempted to contact Dr. Vargas for information
May 19, 2010 - received response from Paul Giordano:

20. Communication from MSU on May 19, 2010
....we believe the bacterium is the causal organism, or at least partially
responsible for the issue....
....we are still in the beginning stages of investigating this problem, and
would like to have sound scientific evidence supporting our conclusions
before giving any concrete answers....
....we would like to initiate some collaborative research with your lab
aimed at positive identification of the problem....

21. Plant Disease Note,
Published June 2009
• ...a golf course putting green sample...
• ...symptoms of general wilt, decline,
and characteristic necrosis...
• ...bacterial streaming was present in all
of the infected tissue...
• ...3 different bacteria were isolated...
• ...one resulted in slight browning of leaf
tips just 2 days after inoculation...

22. Plant Disease Note,
Published July 2009
• ...when leaf tips of the inoculated
plants were cut, bacterial streaming
was observed...
• ...DNA sequencing results indicated
that the causal agent was a member of
the Acidovorax genus...
• ...this is the first report of a bacterial
disease affecting creeping bentgrass
caused by Acidovorax spp. in the US.

23. Photo by P. Giordano, MSU

24. Photo by L.P. Tredway

26. Compendium of Turfgrass Diseases

27. Photo by P. Giordano, MSU

28. Acidovorax avenae
Acidovorax citruli

29. USGA Survey Results
• 51 people participated in the survey
RI
• 30 suspected they had bacterial wilt on
Rutgers
their greens
MSU
• 25 submitted samples to a laboratory for
analysis
Turf Diag.
• 23 had laboratory confirmed diagnosis of
Purdue
bacterial wilt on the samples
NCSU
• The bacterium Acidovorax was identified
in 8 cases 0 3 6 9 12 15
# of samples

30. So now what do we do?
• We need to do the work to figure it out!
• What bacteria are normally associated with healthy and declining
bentgrass?
• Are there bacterial species consistently associated with etiolated or
declining bentgrass?
• Can these symptoms be reproduced through field inoculations with
these bacteria?
• If any are pathogenic, can they be controlled with antibiotics or other
compounds?

31. Scalping Chemical Burn
Heat Herbicide Injury
What bacteria are normally associated with dead and declining
bentgrass?

33. Acidovorax sp.
Xanthomonas translucens
No suspected pathogens

34. Management of Bacterial Disease
ALLEVIATE STRESS!
• raise mowing heights
• reduce mowing frequency
• mow in evening or when turf is dry
• avoid abrasive practices such as aerification or topdressing
• LIGHT and FREQUENT applications of complete foliar fertilizers
• irrigate in morning to prepare for heat of day, ensure that foliage
dries in between syringe cycles

35. What are the chemical control options?
• hydrogen dioxide
• streptomycin sulfate
• oxytetracycline
• ningnamycin
• others?

36. Newer Products for Turf Disease Management

37. What about granular fungicides?

38. Bayleton (1 oz) Fungicide VII (85 oz)

39. Improved granular technology makes foliar disease control possible

40. Fungicides Now Available on Granular Carriers
• Disarm
• Headway
• Heritage
• Insignia

41. Comparison of Granular and Sprayable Fungicides
Armada G (8 lb)
Armada WP (1.2 oz)
Heritage WG (0.2 oz)
Lawn Fungus Control
Untreated
0 5 10 15 20
Brown Patch Incidence (%)
Treatments applied 18 Jun, 16 Jul and 13 Aug

42. Comparison of Granular and Sprayable Fungicides
Heritage G (3 lb)
Compass G (4 lb)
Disarm G (2.3 lb)
Heritage WG (0.2 oz)
Untreated
0 3 6 9 12 15
Brown Patch Incidence (%)
Granular treatments re-applied every 21 days, Heritage 50WG re-applied every 28 days

43. The DMI Fungicides: A Growing Chemical Class
• fenarimol (Rubigan)
• metconazole (Tourney)
• myclobutanil (Eagle)
• propiconazole (Banner Maxx)
• tebuconazole (Torque)
• triadimefon (Bayleton)
• triticonazole (Trinity, Triton)

44. Tourney (metconazole)
• 0.18 to 0.37 oz application rate (0.44 oz
for snow mold)
• 14 to 21 day application interval
• improved control of anthracnose and
brown patch compared to other DMIs
• less growth regulation / injury potential on
cool-season grasses
• not labeled for application to
bermudagrass

45. Trinity (triticonazole)
• 0.5 to 2 oz application rate
• improved brown patch activity
compared to older DMIs
• very good control of
anthracnose, fairy ring, and
summer patch
• safer on cool-season grasses,
but not labeled for application to
ultradwarf bermudagrasses

46. Triton FLO (triticonazole)
• 0.28 to 1.1 fl oz application rate
• includes StressGard pigment
• similar to other triticonazole formulations,
but pigment can reduce negative side
effects
• not for application to ultradwarf
bermudagrasses

47. Torque (tebuconazole)
• 0.6 fl oz application rate
• golf course use only
• Don’t exceed 3.6 fl oz total/year
• not recommended for ultradwarf putting
greens
• great for SDS & fairy ring

48. DMI Fungicides: Issues to Consider
• phytotoxicity
• leaf texture
• reduced density
• slowed recovery
• interactions with growth regulators
• bentgrass vs. bermudagrass

49. DMI Injury is Rate, Interval, and Timing Dependent
Heritage (0.4 oz, 28 d) Triton (2 oz, 14 d)

50. Even a single application can cause significant turf injury.

51. DMI Phytotoxicity on Creeping Bentgrass
Bayleton (1.5 fl oz, 2 apps)
Tartan (2 fl oz, 2 apps)
Tourney (0.37 oz, 4 apps)
Banner Maxx (2 fl oz, 4 apps)
Untreated
0 1.5 3.0 4.5 6.0
Phytotoxicity (0 to 9)
Treatments applied in March and April; data collected on July 10

52. Are the DMIs safe on bermudagrass greens?
Bayleton (1 fl oz)
Banner Maxx (2 fl oz)
Tourney (0.37 oz)
Trinity (2 fl oz)
Triton FLO (1 fl oz)
Untreated
0 1 2 3 4 5
Phytotoxicity (0 to 5)
Treatments applied Aug 20; data collected Sept 1

53. Are the DMIs safe on bermudagrass greens?
Bayleton (1 fl oz)
Banner Maxx (2 fl oz)
Tourney (0.37 oz)
Trinity (2 fl oz)
Triton FLO (1 fl oz)
Untreated
0 10 20 30 40 50 60 70 80 90 100
Recovery (# of aerification holes visible)
Treatments applied Aug 20; data collected Sept 1

54. Be careful when mixing DMIs and PGRs
Trinity (1 fl oz)
Trinity + Cutless (1 fl oz + 4 oz/A)
Trinity + Cutless (1 fl oz + 8 oz/A)
Trinity ALT Cutless (1 fl oz ALT 4 oz/A)
Untreated
0 1 2 3 4 5
Phytotoxicity (0 to 5)

55. DMI-PGR Combinations on Creeping Bentgrass
Fungicide Treatments Growth Regulator Treatments
• Bayleton (1 fl oz) • Primo Maxx (0.125 fl oz)
• Banner Maxx (2 fl oz) • Cutless (6 oz/acre)
• Tourney (0.37 oz) • Legacy (8 oz/acre)
• Trinity (2 fl oz)
• Triton FLO (1.1 fl oz)

56. DMI-PGR Combinations on Creeping Bentgrass
• applications initiated on June 10,
2009
• DMIs applied every 28 days at
highest rate recommended for
foliar diseases
• PGRs applied every 14 days at
typical rates
June 17, 2009

57. DMI-PGR Combinations on Creeping Bentgrass
• growth regulators alone caused more injury than fungicides alone
• DMI-PGR programs can cause increased phytotoxicity when compared
to either applied alone
• Triton FLO caused the least phytotoxicity and actually increased turf
quality over time
• Cutless and Legacy caused more phytotoxicity than Primo Maxx
• negative side effects reduced over time with continued use