Turf Disease Management: Can it be done without fungicides?
1. Turf Disease Management:
Can it be done without fungicides?
Lane Tredway
Associate Professor and Extension Specialist
Department of Plant Pathology
North Carolina State University
2.
3.
4. What is sustainable?
capable of being continued with minimal long-
term effect on the environment (American
Heritage Dictionary)
of, relating to, or being a method of harvesting or using
a resource so that the resource is not depleted or
permanently damaged (Merriam-Webster)
capable of being maintained at a steady level
without exhausting natural resources or causing
ecological damage (Collins)
5. Which practice is least sustainable?
1. removing trees to increase sunlight and air movement
2. planting a variety containing resistance genes from
grasses collected in Poland
3. planting a variety containing frog dermaseptin genes
4. applying the biofungicide Rhapsody (Bacillus subtilis)
5. applying fungicide Heritage (azoxystrobin)
6. applying a mixture of soda, beer, soap, ammonia, and
mouthwash
6. Which practice is most sustainable?
1. removing trees to increase sunlight and air movement
2. planting a variety containing resistance genes from
grasses collected in Poland
3. planting a variety containing frog dermaseptin genes
4. applying the biofungicide Rhapsody (Bacillus subtilis)
5. applying fungicide Heritage (azoxystrobin)
6. applying a mixture of soda, beer, soap, ammonia, and
mouthwash
7.
8.
9.
10.
11. How do plant diseases develop?
Di
se
as
e-
st
Co
Ho
n
du
e
ibl
c
t
ive
ep
Amount of
sc
En
Disease
Su
vir
on
me
nt
Pathogen
14. How are turfgrass diseases managed?
Di
se
as
e-
st
Co
Ho
n
du
e
ibl
c
t
ive
ep
Amount of
sc
En
Disease
Su
vir
on
me
nt
Pathogen
15. How are turfgrass diseases managed?
Plant a disease-
resistant Dise
ase-
species or Con
duc
variety ive En
viron
25% Disease men
t
Pathogen
16. How are turfgrass diseases managed?
Plant a disease- Remove trees to
resistant species increase sunlight
or variety and air movement
10% Disease
Pathogen
17. How are turfgrass diseases managed?
Remove trees
Plant a disease-
to increase
resistant species
sunlight and
or variety
air movement
2% Disease
Apply a fungicide to
suppress pathogen
growth
18. 0% 5% 10%
Establish a threshold. How much damage is acceptable?
En
vir
st
on
Ho
me
nt
Pathogen
20. Turf Species Vary in their Disease Susceptibility
Kentucky bluegrass - summer patch, dollar spot, leaf spot,
rust
perennial ryegrass - dollar spot, red thread, Pythium blight,
gray leaf spot, brown patch, rust
tall fescue - brown patch
fine fescues - dollar spot, summer patch, red thread
st
Ho
27. EVERY turf disease is influenced by nitrogen.
Anthracnose Brown Patch
Dollar Spot Pythium Blight
Fairy Ring Gray Leaf Spot
Pythium Root Dysfunction Spring Dead Spot
Red Thread Large Patch
Rust Snow Molds
Low Nitrogen High Nitrogen
46. Environmental Impact Quotient (EIQ)
What’s the real environmental impact?
http://www.nysipm.cornell.edu/publications/eiq/
47. Product Rate/1000 ft2 Interval EIQ/month
Heritage 50WG 0.2 oz 28 days 7.3
Rhapsody 5 oz 7 days 7.6
Bayer Fungus
2 lbs 14 days 28
Control
Scotts Lawn
1.35 lbs 14 days 64
Fungus Control
Daconil Ultrex 3.2 oz 14 days 538
Pathogen
48. Too
many
fungicides
to choose from!
flickr:kanickmoses
56. What about biological control?
Biologicals
• a living organism is applied to the turf, which may inhibit disease
through a variety of mechanisms
Biofungicides
• an inhibitory compound, derived from a specific microbe, is
concentrated and applied to the turf
Composts
• stimulate activity of soil microbes
• some of which may be beneficial
• some may be harmful or pathogenic
57. Rhapsody (2%) Rhapsody (3%) Untreated
200
Dollar Spot Incidence
150
*
*
100
50
0
4 May 18 May 1 Jun 15 Jun 1 Jul 15 Jul
Rhapsody applied every 14 days
58.
59. How to follow along...
turfpathology.org
facebook.com/turfpathology
twitter.com/ncturfpathology
feeds.feedburner.com/turfpathology