Alison Robertson Charlie Hurburgh Lisa Shepherd Charlie Block and Roger Elmore 21 July 2 August 25 August Gosss leaf blight disease progress 9 September Q Where was Gosss wilt in ID: 443813
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Slide1
Goss’s wilt: Get the facts!
Alison Robertson
Charlie Hurburgh Lisa ShepherdCharlie Block and Roger ElmoreSlide2
21 July
2 August
25 August
Goss’s leaf blight disease progress
9 SeptemberSlide3
Q. Where was Goss’s
wilt in
Iowa in 2011?Slide4
Usually first seen on top leaves
Q. What symptoms occur with Goss’s wilt?Slide5
May be seen in mid canopy
Q. What symptoms occur with Goss’s wilt?Slide6
Wavy, margin
Greasy “Freckles”
Q. What symptoms occur with Goss’s wilt?Slide7
“Freckles”
Saprophytic fungi
Q. What symptoms occur with Goss’s wilt?Slide8
Q. Is there a kit to diagnose Goss’s wilt?
Clavibacter michiganensis
subsp
michiganensis
Cost:
5 for $32.50
25 for $120
5-10 mins
ImmunoStrip
Test (
Agdia
®)Slide9
CAREFUL!!!!!
False positives
example: Purple leaf sheath; other saprophytic bacteria on corn.
Extremely sensitive
cross contamination between samples
Purple leaf sheath
Q. Is there a kit to diagnose Goss’s wilt?Slide10
ICM 2008
Q. Has a new race of
Cmn evolved?
Race:
a subgroup or biotype within a species
Usually distinguished from other races by
virulence
symptom expression
or host range
but not by morphology
(D’
Arcy
et al. 2001)Slide11
ICM 2008
Q. Has a new race of
Cmn evolved?
1a
1b
1c
1k
2
3a
3b
3c
4
5
6
7
8
1d
C
Standardized soybean lines are used to identify races of
P. sojae
Slide12
ICM 2008
Q. Has a new race of
Cmn evolved?
Rpp
9 resistance to Southern rust fungus
Puccinia
polysora
Photo courtesy of B. Dolezal, PioneerSlide13
ICM 2008
Q. Has a new race of
Cmn evolved?
Ht
1 resistance to
Northern leaf blight fungus
Helminthosporium
turcicum
Race 1
Race 0
Photos courtesy of B. Dolezal, PioneerSlide14
ICM 2008
Q. Has a new race of
Cmn evolved?
131 strains of
Cmn
1969 – 2009
origin Slide15
ICM 2008
Two groups: A and B
A: no correlation with strain,
xxi
origin
, history
B: all strains collected after 1999
13/69 strains = <20%
(
Agrakova
et al., 2011)Slide16
Cmn
bacteria ooze from residue; splash dispersed
Bacteria overwinter in infested crop residue and seed
Goss’s
disease
cycle
Symptoms
Epiphytic infection
InfectionSlide17
Goss’s wilt bacterium survives for at least
10
xxi
months
in infested surface crop residue
Survival is significantly reduced in buried residue
0”
4”
8”
Leaves
80
0
0
Stalks
75
30
40
Cobs
63
5
0
Pure culture
0
0
0
Goss’s Disease Index
(Schuster, 1975)
Q. How long does
Cmn
survive in corn residue?Slide18
Can
Cmn
survive longer? Slide19
Survival
C. m.
subsp. michiganensis on tomato
Buried infested residue: ~7 months
Surface infested residue: 2 years
Gleason et al., 1991Slide20
What effect might corn
stover
removal have? Slide21
Percent corn residue and GLS disease severity
de
Zareno
and
Lipps
, 1993
More residue = greater diseaseSlide22
What effect does manure have on survival of
Cmn
?
Population of
C.m
.
subsp
.
sepedonicus
on potato decreased as other microbes in cattle manure slurry increased
(
Roozen
and Vanvuurde 1991)
Composts amended with cattle or poultry manure reduced C. m. subsp. michiganensis
of tomato (tomato canker) by 79 to 100%Populations of C. m. subsp. michiganensis in composts declined to undetectable levels in 15 to 21 days
(Yogev et al, 2009)Slide23
Biddle et al, 1990
Q. Was Goss’s wilt introduced on
Cmn-infected seed?
Seedborne
infection (seed infection):
pathogen
carried on or in a seed
Seed transmission:
pathogen in or on seed infects developing seedlingsSlide24
Biddle et al, 1990
Inoculated field trial
Leaves of plants inoculated at V3, V6 and VT
Seed infection: 17.1 - 30.7%
Seed transmission: none detected (N=12000 seed)
Biddle et al., 1990
Q. Was Goss’s wilt introduced on
Cmn
-infected seed?
Natural infection in field
Seed naturally infected with Goss’s wilt
Seed infection: 2 – 39%
Seed transmission: 1 in 12864 seedlings.
- single case found in 29% seed lot
Shepherd, 1999 & 2011Slide25
Several common weeds are secondary hosts of
Cmn
Green foxtail
Shattercane
Sudangrass
Eastern
gamagrass
Q. Are there other hosts of
Cmn
?
Schuster, 1975Slide26
Other susceptible hosts: sugarcane –atypical symptoms
Resistant to infection:
Oats
Barley
Wheat
Bromegrass
Orchardgrass
Crabgrass
Barnyard grass
Proso
millet
Yellow foxtail
Johnson grass
Sugarbeet
cabbage
Chrysanthemum
Poinsettia
Tomato
Petunia
Potato
Schuster, 1975
Q
. Are there other hosts of
Cmn
?Slide27
Several genes
quantitatively inherited
not complete, i.e. no immunity knowneither leaf blight or wilt
Q. Is there resistance to
Cmn
?
115
bu
/acre yield differenceSlide28
Effect of Goss’s leaf blight on grain characteristics
9 fields
7 in Central IA; 2 in SW Iowa
8 hybrids from 3 major seed companies
2 to 11 locations per field
Goss’s leaf blight severity at R3 or R5
Stalk rot severity prior to harvest
20 ears hand harvested per locationSlide29
r=0.61 P=0.01
Robertson et al., 2011
Goss’s leaf blight severity and stalk rotSlide30
Variable
<
5% at R5
>5
% at R5
P
value
# rows
16.4
(14.5-18.6)
16.9
(15.3-17.9)
0.175
#
kernels per row
31.9
(29.2-34.6)
31.5
(29.7-32.6)
0.286
Seed weight (g/1000)
402.4
(327.8-472.0)
327.8
(245.2-395.6
)
0.0001
Robertson et al., 2011
Effect of Goss’s leaf blight on grain characteristicsSlide31
Assessment
<
5% at R5
>
5% at R5
P
value
Test Weight @ 15% moisture (lb/
bu
)
57.0
(55.2-60.3)
55.7
(53.6-60.6)
0.049
Starch (%)
60.8
(60.1-61.8)
61.3
(60.7-62.1)
0.041
Protein, oil and density: NS
Robertson et al., 2011
Effect of Goss’s leaf blight on grain characteristicsSlide32
r=-0.51 P=0.007
Robertson et al., 2011
8 hybrids
Goss’s leaf blight severity and seed sizeSlide33
r=-0.77 P=0.001
Robertson et al., 2011
2 hybrids
Goss’s leaf blight severity and seed sizeSlide34
r=-0.87 P<0.001
Robertson et al., 2011
2 hybrids
Goss’s leaf blight severity and estimated yield lossSlide35
Goss’s leaf blight severity and test weight
r = - 0.83 P=0.0002
Robertson et al., 2011
2 hybridsSlide36
Goss’s leaf blight severity and seed infection
Goss's
severity (%)
Growth
stage
Seed Infection
Seed Transmission (positive/ tested)
1
R3
5
R5
5
R3
5
R5
5
R5
15
R3
20
R5.25
20
R3
35
R5.75
100
R5.5
100
~R5Slide37
Goss’s leaf blight severity and seed infection
Goss's
severity (%)
Growth
stage
Seed Infection
Seed Transmission (positive/ tested)
1
R3
0/200
5
R5
5
R3
0/200
5
R5
0/200
5
R5
0/200
15
R3
0/200
20
R5.25
20
R3
0/200
35
R5.75
0/145
100
R5.5
1/145
100
~R5
10/400Slide38
Goss’s leaf blight severity and seed infection
Goss's
severity (%)
Growth
stage
Seed Infection
Seed Transmission (positive/ tested)
1
R3
0/200
5
R5
0/755
5
R3
0/200
5
R5
0/200
5
R5
0/200
15
R3
0/200
20
R5.25
0/768
20
R3
0/200
35
R5.75
0/145
0/1154
100
R5.5
1/145
0/1233
100
~R5
10/400
0/760Slide39
Risk factors for Goss’s wilt and leaf blight
Susceptible hybrid
Continuous corn
Percent surface residue
Goss’s wilt in 2011
(Severe storms)Slide40
Management in 2012
Resistant hybrid
Rotation
Residue managementSlide41
Thanks for attending!
What questions do you have?