The Surprising Bunts and Smuts “Still a threat after all these years” James G. Menzies, AAFC, Winnipeg Manitoba Denis Gaudet, AAFC, Lethbridge, Alberta
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The Surprising Bunts and Smuts“Still a threat after all these years”
James G. Menzies, AAFC, Winnipeg Manitoba
Denis Gaudet, AAFC, Lethbridge, Alberta
2
Bunt and Smut Pathogens of Barley, Oats and Wheat
Smut FungiBasidiomycetes
UstilaginalesTilletiaceae35 species
Important Species on the Prairie ProvincesUstilago spp. – Smut diseasesTilletia spp. – Bunt diseases
3
Wheat Diseases
• Seedling Infecting Diseases
• Common Bunt• (Tilletia laevis, T. tritici)
• Dwarf Bunt (T. controversa)• Karnal Bunt (T. indica)
• Flag Smut (Urocystis agropyri)
• Floral or Embryo Infecting Disease
• Loose Smut (Ustilago tritici)
4
Barley Diseases
• Seedling Infecting Diseases
• Covered Smut (U. hordei)False Loose Smut (U. nigra)
• Floral or Embryo Infecting Disease
• Loose Smut (Ustilago nuda)
5
Oat Diseases
• Seedling Infecting Diseases
• Covered Smut (U. kolleri)Loose Smut (U. avenae)
6
Worldwide Distribution of Common Bunt and Loose Smut
Wilcoxson and Saari, eds. 1996. Bunt and Smut Diseases of Wheat: Concepts and Methods of Disease Management. Mexico, D.F.: CIMMYT
7
Life (Disease) Cycles of Seedling Infecting and Floral or Embryo Infecting Smut Fungi
Bailey, Gossen, Gugel and Morrall. 2003. Diseases of Field Crops in Canada. The Canadian Phytopathological Society.
8
Conditions Affecting Loose Smut
• Favouring Development– Cool moist weather during flowering (95% RH, 20-25oC)– Conditions that extend the flowering of the host (more time to
infect).
• Detrimental to Development– Excessive heat and dry weather during flowering– Adverse environmental conditions during host development
may affect disease expression (i.e. low temperature).– Fusarium graminearum
9
Conditions Affecting Common Bunt
• Favouring Development– Soil temperatures between 5 to 10oC– Infection can occur with soil moisture between permanent
wilting point and field capacity – optimum in the middle.– Deep seeding – as soil depth increases, the soil temperature
becomes more favourable for the pathogen.
• Detrimental to Development– Warm soil temperatures (infection is low at 22oC)– Other soil factors are not critical to disease development.
10
Occurrence of Loose Smut of Wheat in Manitoba and Saskatchewan
0
10
20
30
40
50
60
70
80
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009Year
Perc
ent i
ncid
ence
hexaploid wheatdurum wheat
11
Occurrence of Loose Smut of Barley in Manitoba and Saskatchewan
0
10
20
30
40
50
60
70
80
90
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009Year
Perc
ent i
ncid
ence
6 Row2 Row
12
Percentage Infection in Most Affected Fields –Manitoba and Saskatchewan
0
2
4
6
8
10
12
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009year
perc
ent h
ighe
st in
fect
ion
hexaploid wheatdurum wheat
13
Percentage Infection in Most Affected Fields –Manitoba and Saskatchewan
0
5
10
15
20
25
30
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Year
Perc
ent h
ighe
st in
fect
ion
6 row2 Row
14
Symptoms of Loose Smut
• Smutted Spikes
• Narrow lines of sori on the flag leaf– More common in
barley
• Reduced tillers
• After heading, smutted plants may stop growing
Symptoms may not be readily visible at harvest.
15
Symptoms of Common Bunt
• May not be apparent until after heading
• Immature infected spikes are darker green and remain green longer.
• Mature spikes are slightly lighter in colour with a slight bluish grey colour compared to healthy spikes.
• Florets may be slightly flared, but have a near normal appearance.
16
• Common Bunt and Loose Smut have not been a problem since the middle of the 20th century because of effective control
practices, including the use of seed treatment fungicides and
host resistance.
Significant losses can still occur in individual fields or over small
areas, largely as a result of improper application of control
techniques or complacency.
17
Disease Management
• Many of the techniques used to control Loose Smut and Common Bunt are similar.
• Use Resistant Varieties when available.
18
Resistance of Barley Varieties Listed in Seed Manitoba
Malting Barley
(26)
Feed Barley
(25)
Hulless Barley
(4) Resistance
Very Good 4 2 3 Good 0 0 0 Fair 5 2 0 Poor 9 17 1
Loose Smut
Very Poor 8 4 0
Very Good 4 10 1 Good 11 8 2 Fair 7 5 1 Poor 3 2 0
Seedling Infecting
Smuts
Very Poor 1 0 0
19
Resistance of Oat Varieties Listed in Seed Manitoba
Oats (17)
Hulless Oats (6)
Resistance
Very Good 13 5 Good 0 0 Fair 1 0 Poor 2 0
Seedling Infecting
Smuts
Very Poor 0 0
20
Resistance of Wheat Varieties Listed in Seed Manitoba
CWRS CPS
(R) CPS (W)
CWES CWHWS
(35) (6) (1) (5) (2) Resistance
Very Good
6 1 5
Good 14 Fair 8 2 Poor 7 4 2
Loose Smut
Very Poor
Very Good
17 4 1 1
Good 1 1 Fair 13 2 4 Poor 4 1
Bunt
Very Poor
21
Resistance of Wheat Varieties Listed in Seed Manitoba
CWSWS CWGP CWAD CWWW (2) (2) (10) (2) Resistance
Very Good
Good Fair 1 Poor 2 1 8
Loose Smut
Very Poor 2
Very Good
2 10
Good 1 Fair Poor 1 1
Bunt
Very Poor 1
22
Long Term Natural Infection Experiments
0
1
2
3
4
5
6
Years
1992
1994
1996
1998
2000
2002
2004
2006
Year
Perc
ent I
nfec
tion
Very PoorPoor to FairGood
23
Disease Management
• Seed Treatment Fungicides– Highly effective
• Systemic fungicides are necessary for loose smut of wheat and barley• Contact or protectant seed treatments are effective for bunts and the
seedling infecting smuts - Placement is often at the point of infection
– Number on the market• Fungicide resistance – carboxin resistance has been identified
for the loose smut fungi• Fungicide rotations should be practiced. Different modes of
action of the fungicides needs to be stressed.
24
Disease Management
• Disease Free Seed– Certified Seed– Embryo Test (Loose Smut)
• Bunts– Crop Rotation – Bunt spores
can survive for 2 years– Seed into warm soils, early
fall or late spring• Seed shallow (4 cm instead
of 7 cm)
25
Disease Management
• Hot Water Treatments– 1) Immerse seed in water at 54oC for ½ hour, then cool
immediately.– 2) 20oC water for 5 hours; 49oC for 1 minute; 52oC for 11
minutes; cool water immediately– Need to increase your seeding rate.
Le ChaulageSoak seed in a copper pannier in a mixture of sheep’s urine and milk of lime (portlandite or calcium hydroxide)
26
Conclusions
• The smut and bunt diseases of small grain cereals were once diseases of large impact to agriculture
• These diseases are not major problems today because of modern agricultural practices; in particular, the use of resistant varieties and seed treatment fungicides.
• Although these pathogens are of minor importance in modern agriculture, they can be commonly found in western Canada, albeit at low severities.
• Smut and bunt diseases can still cause losses as a result of improper control practices or complacency.
27
Thank you!
Related Documents
