Transcript Levels of Stewart’s wilt control necessary to prevent www.sweetcorn.uiuc.edu

Levels of Stewart’s wilt
control necessary to prevent
yield losses in sweet corn
Jerald K. Pataky
Professor of Plant Pathology
Department of Crop Sciences
University of Illinois
[email protected]
www.sweetcorn.uiuc.edu
• background on Stewart’s wilt
Work at Illinois
• flea beetles dynamics
• yield losses
• seed treatment control
• host resistance
Corn flea beetle
Stewart’s wilt
Erwinia stewartii
seedling wilt phase
Flea beetle winter survival
Average daily air temperature
Dec., Jan., Feb.
> 33 F
27 - 32 F
< 27 F
many survive*
% survive*
killed
*size of population from previous season
affects size of overwintering population
NE Stevens, 1934. Plant Dis. Rpt. 18:141-149
GH Boewe, 1949. Plant Dis. Rpt. 33:192-194
Ten Warmest Winters
(Columbia, MO - since 1895)
10.
9.
8.
7.
6.
5.
4.
3.
2.
1.
1930-1931
1952-1953
1999-2000
1908-1909
1998-1999
1953-1954
1920-1921
1997-1998
1991-1992
1931-1932
36.2
36.2
36.2
36.3
36.4
36.8
36.9
36.9
37.9
40.0
Laura Sweets, University of Missouri, Columbia
Golden Cross Bantam
released in 1932
Glenn Smith
USDA
Purdue Univ
“I shall never cease to be thankful that we had that epidemic of bacterial
wilt from 1930 t0 1933, for without that bit of good luck, we might never
have discovered the possibilities of Golden Cross Bantam.”
Ten Warmest Winters
(Columbia, MO - since 1895)
10.
9.
8.
7.
6.
5.
4.
3.
2.
1.
1930-1931
1952-1953
1999-2000
1908-1909
1998-1999
1953-1954
1920-1921
1997-1998
1991-1992
1931-1932
36.2
36.2
36.2
36.3
36.4
36.8
36.9
36.9
37.9
40.0
Laura Sweets, University of Missouri, Columbia
Two important generations
of flea beetles
• overwintering generation
- population peaks at first plantings
- decreases until ~ Memorial Day
• first summer generation
- peaks between June 20 to July 10 (GDD?)
- size affected by weather (larger when dry)
• subsequent generations
- late-season leaf blight (phytosanitary issues)
- become OW population for next year
Seasonal
fluctuations in
populations of the
corn flea beetle and
incidence of
Stewart’s wilt in
sweet corn
Kelly Cook
MS thesis, Univ. of Illinois
2003
Advisor: Rick Weinzierl
Materials and Methods
Material and Methods
Materials and Methods
Results
2001 Ave FB/Trap/Day
40
Dixon Springs
Brownstown
35
Ave FB/Trap/Day
Champaign
30
Mendota
25
OW gen.
20
1st
summer
gen.
15
10
5
0
100
120
140
160
180
200
220
240
260
Date
April
May
June
July
August
September
280
300
Results
Stewart’s wilt vs. flea beetles
100
90
80
Peak SW
70
60
50
40
30
20
10
0
0
10
20
30
40
50
FB/Trap/Day
60
70
80
90
100
Results
Levels of Stewart’s wilt vs. flea beetles
Average
Beetle
Density
(FB/Trap/
Day)
Number (and percentage) of plots in which
the peak incidence of Stewart’s wilt was
low, moderate, or high
Low
(<5 %)
Moderate
(5 to 10 %)
High
(>10 %)
5 or less
25 (80.6 %)
2 (6.5 %)
4 (12.9 %)
>5
8 (23.5 %)
5 (14.7 %)
21 (61.8 %)
20012002
Effect of Stewart’s wilt
on sweet corn yield
• growth stage
• level of resistance
Effects of Stewart’s wilt on yield - hybrid nursery
Phytopathology 78:172-178, 1988
Stewart’s wilt and sweet corn yield
effect of growth stage at time of infection
Suparyono, 1987 Plant Dis. 73:339-345
Effects of Stewart’s wilt on
yield losses in sweet corn
Growth stage when infected
Hybrid
3- to 5- 5- to 7reaction leaf
leaf
R
MR
MS
S
7- to 9leaf
0%
0%
0%
0-30%
0%
0%
10-40%
0-20 % 0 %
40-100% 15-35% 3-15%
• prior to 3-leaf stage -- main stalks may be killed
Suparyono 1987, Pataky et. al. 1988
Main stalk death
Growing point is killed
Tillers from main stalk death
Stewart’s wilt and main stalk death
Hybrid
Bold
GH 2628
Bonus
More
GH 2757
Empire
Jubilee
July 1995, Manito, IL
Main stalk
death (%)
10%
11%
11%
17%
30%
33%
60%
Hybrid
Rxn
MR
R/MR
R
R/MR
MS
M/MS
S
Plant Dis. 80:104
Stewart’s wilt
rating scale
1 to 4: non-systemic
1:
2:
3:
4:
2-3 cm
~ 10 cm
tip end of leaf
both ends of leaf
5 to 9: systemic
• leaf area infected
• stunting
9: dead (might as well be)
www.sweetcorn.uiuc.edu
1
5-6
2-3
7
Percent yield (ear weight)
120
100
80
60
2000
1999
40
2
20
Y = 80.9 + 13.7X - 2.9X
2
r = 0.75
0
2
3
4
5
6
7
Stewart's wilt rating
Fig. 6. 1999 and 2000 combined regression,
Yield and
Stewart’s
wilt
reactions
relationship
between
percent
yield
(ear weight)
Freeman, 2001. Plant Dis. 85:1278-1284
and Stewart's wilt rating
Stew art's w ilt incidence
(%)
100
Y = 3.0 - 6.5X + 2.4X2
r2 = 0.86
80
60
40
20
0
1
2
3
4
5
6
7
8
Stew art's w ilt rating (1-9)
Stewart’s wilt ratings and
Fig. 3. Relationship between incidence of
incidence
(%) of and
systemic
infection
systeic infection
Stewart's wilt
ratings
Freeman 2001 Plant Dis. 85:1278-1284
120
Percent yield
100
80
60
40
Y = 101.3 - 0.8X
20
r 2 = 0.77
0
0
20
40
60
80
100
Systemically infected plants (%)
Fig. 5. Relationship between percent yield
Yieldand
and
systemic
infection
incidence (%) ofFreeman
systemic
infection
2001 Plant Dis. 85:1278-1284
Marketable ears and
incidence of systemic infection
Percent marketable ears
120
100
80
60
40
20
Y = 93.0 - 0.93X
2
r = 0.65
0
0
20
40
60
80
Systemically infected plants (%)
100
To avoid yield losses
from Stewart’s wilt
• under normal conditions
• levels of control that prevent
systemic infection
• under severe conditions
• as much control as possible
(very early infection - main stalk death)
Control Stewart’s wilt
• control flea beetles
• resistant hybrids
Controlling flea beetles
Insecticides
• seed treatments
• in-furrow applications
• foliar applications
Seed treatment
insecticides
60% to 80% control
of Stewart’s wilt
• imidacloprid (Gaucho)
• thiamethoxam (Cruiser)
• clothianidin (Poncho)
Plant Dis. 84:1104-1108, 2000
treated
non-treated
Rates of clothianidin, imidacloprid, and
thiamethoxam to conrtol Stewart’s wilt
2000 April 26
April 27
June 19
June 22
2001 April 25
April 25
2002 April 16
June 30
July 8
July 8
2003 July 22
Stewart’s wilt
(non-treated)
Manito, IL
28%
Urbana, IL
41%
Urbana, IL
91%
Manito, IL
26%
Newark, DE
9%
Newark, DE
9%
Urbana, IL
8%
Urbana, IL
9%
Brownstown, IL 44%
Brownstown, Il 25%
Urbana, IL
16%
Range
of control
72 - 94%
65 - 87%
65 - 73%
52 - 73%
75 - 81%
55 - 82%
41 - 91%
46 - 83%
67 - 92%
44 - 79%
67 - 86%
rates of seed treatment insecticides from 0.125 to 1.25 mg per kernel
Stewart’s wilt control on Jubilee
Incidence (%) of systemic Sewart's wilt
30
Manito early trial (Planted: 26 April)
25
2 June
22 June
20
15
10
5
0
Check Adage
50
Adage
100
Adage
200
Adage Gaucho Gaucho Gaucho
250
3.2
4.8
6.2
G2
4
G2
8
Stewart’s wilt control on Jubilee
Incidence (%) of systemic Stewart's wilt
100
Urbana late trial (Planted: 19 June)
90
10 July
80
20 July
70
4 August
60
50
40
30
20
10
0
Check Adage
50
Adage
100
Adage
200
Adage Gaucho Gaucho Gaucho
250
3.2
4.8
6.2
G2
4
G2
8
Rates of insecticides
Stewart's wilt control as a % of non-treated
100
90
80
70
60
b1 = 18.5%
50
b0
clothianidin 70.1
imidacloprid 61.3
thiamethoxam 62.4
40
0
0.2
0.4
0.6
0.8
1
1.2
Rates of seed treatment insecticides (mg ai / kernel)
1.4
Control Stewart’s wilt
• Poncho
• 0.25 mg/kernel
• 1.25 mg/kernel
75% control
93% control
• Cruiser
• 0.25 mg/kernel
• 1.25 mg/kernel
67% control
85% control
• Gaucho
• 0.675 mg/kernel
75% control
Economic value of
seed treatment insecticides
Value = value of the crop ($/A) x incidence (%)
of Stewart’s wilt x % control *
x 0.9 (yield loss regression coefficient)
* control depends on rate and compound
Example:
Crop value estimated at $325/A
x 0.05 (5% systemic infection w/o control)
x 0.75 (75% control)
x 0.9 (yield loss)
= $10.97 / A estimated value of seed treatment
if 5% Stewart’s wilt w/o control
Processing sweet corn - $325 / acre
6.5 ton / A x $50 / ton
Value ($ / 0.4ha) of seed treatment .
90
C
0.67
0.75
0.86
0.93
80
70
thiamethoxam 0.25
clothianidin 0.25
thiamethoxam 1.25
clothianidin 1.25
60
50
40
30
20
Y = $325 x [(C)(X/100)] x 0.9
10
0
0
5
10
15
20
Stewart's wilt incidence (%) non-treated
25
30
Fresh market sweet corn - $1625 / acre
325 crates / A x $5 / crate
Value ($ / 0.4 ha) of seed treatments .
140
C
0.67
0.75
0.86
0.93
120
100
thiamethoxam 0.25
clothianidin 0.25
thiamethoxam 1.25
clothianidin 1.25
80
60
40
20
Y = $1625 x [(C)(X/100)] x 0.9
0
0
1
2
3
4
5
6
7
8
Stewart's wilt incidence (%) non-treated
9
10
Difference in value ($)
1.25 vs 0.25 mg / kernel
Poncho vs. Cruiser
Difference in value ($ per 0.4 ha) of treatments
140
Fresh market: 1.25 vs 0.25 mg
Fresh market: clothianidin vs thiamethoxam
120
Processing: 1.25 vs 0.25 mg
Processing: clothianidin vs thiamethoxam
100
80
60
40
20
0
0
10
20
30
40
Stewart's wilt incidence (%) - no control
50
Seed treatment
control of Stewart’s wilt
• Processing
• treat if expect > 4-5% Stewart’s wilt
• least expensive treatment*
* assumes no other insect control
• Fresh market
• treat if expect any Stewart’s wilt (~1%)
• most effective** treatment
** does not affect germination
Incidence of Stewart’s wilt on sweet corn
hybrids with different levels of resistance
2003
Planting date
North central IL
Monmouth
April 15
Dwight
April 25
Goodfield
April 27
Central IL
Perry
April 14
New Berlin
April 14
Urbana
April 24
Southern IL
Belleville
May 23
Carbondale
May 24
Brownstown
May 28
R-MR
MR-MS
MS-S
0.1
0
0
0
0
0
0.2
0
0.1
0.2
0
0.1
2.4
0.9
0.7
7.7
7.4
2.3
0
0
0.1
0.3
1.0
0.5
0.5
5.7
1.9
2003 Stewart’s wilt
• R-MR
• Bonus
• Summer Sweet 7630
• MR-MS
• Incredible, Crisp N Sweet 710
• GH 1829, Even Sweeter
• MS-S
• Snow White, Lumina
• Supersweet Jubilee, Jubilee
Stewart’s wilt resistance
Commercial sweet corn hybrids -2003
Number of hybrids
140
n = 634
120
100
80
60
40
20
0
R
MR
M
MS
Stewart's wilt reactions
S
Early season vs. full season
40
Early season
Full season
Number of hybrids
35
30
25
20
15
10
5
0
R
MR
M
MS
Stewart's wilt reaction
S
Mid season vs. main season
45
Mid season
Main season
Number of hybrids
40
35
30
25
20
15
10
5
0
R
MR
M
MS
Stewart's wilt reaction
S
Open-pollinated sweet corn cultivars
Number of OP cultivars
14
12
Miracle (R) = 2.6
SS 7710 (MR) = 3.6
Jubilee (S) = 6.7
10
8
6
Stowell's Evergreen
Country Gentleman
Golden Bantam
4
2
R
MR
2
3
4
5
6
7
Stewart's wilt reactions
S
0
1
8
9
du toit, Tracy, Revilla, Plant Dis. 82:939-944, 1998
White, food-grade corn hybrids
80
Number of hybrids
70
Bonus (R) = 2.1
Even Sweeter (M) = 3.9
Jubilee (S) = 6.1
B73 x Mo17 = 2.4
60
50
40
30
20
R
10
M
S
0
1
2
3
4
5
6
7
Stewart's wilt ratings
8
9
Michener, Plant Dis. 86:167-172, 2002
Reactions of PI accessions
Number of accessions
500
400
US accessions
Non-US accessions
300
200
100
0
1.0 - 2.0 - 3.0 - 4.0 - 5.0 - 6.0 - 7.0 - 8.0 1.99 2.99 3.99 4.99 5.99 6.99 7.99 8.99
9
Stewart's wilt rating
du Toit, Freeman, Plant Dis. 84:901-906, 2000
Reactions of PI accessions
Region where
collected
n
Africa
82
South America
207
Europe
582
Central America 44
Asia/Middle East 138
United States
938
SW Rating
mean
<2
4.1
0
4.2
0
4.3
5
4.4
0
4.4
0
3.7
33
Reactions of PI accessions
Region US
where collected
Mid-Atl./Ohio RV
South
West/SW
Corn Belt
unknown
Northeast*
* mostly OP sweet corn
n
245
169
115
315
33
60
SW
mean
3.1
3.7
4.0
4.0
4.0
4.6
Rating
<2
23
1
2
7
0
0
Distribution of Stewart’s wilt
Elliott, 1941. USDA Bull.
Stewart’s wilt resistant accessions
Line
Origin
Va 37
VA
Pa 891
PA
Va 59
VA
Inbred 1032 Spain
SD 40
SD
Va 17
VA
Mo 17
MO
Inbred 1037 Spain
W 182B
WS
B 85
IA
SW
1.4
1.5
1.5
1.6
1.6
1.6
1.6
1.7
1.7
1.7
Line
Origin
89S4154
NB
Va 22
VA
Va 38
VA
Va 24
VA
KYWS6
KY
KYWS5
KY
M14
IL
W 64A
WS
Va 21A
VA
B 84
IA
SW
1.8
1.8
1.8
1.8
2.0
2.0
2.1
2.1
2.2
2.2
Freeman, MS thesis, 2001
Many potential sources of Stewart’s wilt resistance
• look at sweet corn first
Stewart’s wilt resistance of Bonus
Bonus S2 lines - Stewart's 2001-2002
Stewart'swilt ratings - 2002
7
2001 2002
mean 3.58 3.36
sd
1.08
0.88
BLSD 0.94
0.82
6
5
4
3
2
n = 110
r = 0.82
1
1
2
3
4
5
Stewart's wilt ratings - 2001
6
7
Heritability and markers
h2 = 0.85
bnlg2248
bnlg1902
umc1296
2:58
5:61
6:130
*** AA
*** bb
*** CC
n
SW
bnlg 2248 (2:58)
homozygous R
heterozygotes
homozygous S
31
43
34
3.1
3.3
3.9
bnlg 1902 (5:61)
homozygous R
heterozygotes
homozygous S
41
39
28
3.1
3.6
3.8
umc 1296 (6:130)
homozygous R
heterozygotes
homozygous S
33
27
42
3.2
3.2
3.9
three
resistance
markers
A-bbC-
one
resistance
marker
two
resistance
markers
A-C-
bbC- A-bb
A-
bb
no
resistance
markers
C-
Mean Stewart's wilt rating
5
4
3.79
3.21
3
3.37
4.16
4.22
aaB-C-
aaB-cc
3.92
3.48
2.66
2
1
A-bbC-
A-B-C-
aabbC-
A-bbcc
A-B-cc
Genotype
aabbcc
16
14
Number of lines
12
10
Loci
Means
Three 2.66
Two
3.27
One
3.92
Zero
4.22
Three
Two
One
Zero
8
6
4
2
0
1-1.5
1.5-2
2-2.5
2.5-3
3-3.5
3.5-4
Stewart's wilt ratings
< 2.5
13 of 14 had 3 or 2
4-4.5
4.5-5
>5
16
14
Number of lines
12
10
Loci
Means
Three 2.66
Two
3.27
One
3.92
Zero
4.22
Three
Two
One
Zero
8
6
4
2
0
1-1.5
1.5-2
2-2.5
2.5-3
3-3.5
3.5-4
4-4.5
4.5-5
>5
Stewart's wilt ratings
< 2.5
13 of 14 had 3 or 2
>4
22 of 24 had 0 or 1
Resistance from S2 families - 465 and 467
Bonus S2 lines - Stewart's 2001-2002
Stewart'swilt ratings - 2002
7
2001 2002
mean 3.58 3.36
0.88
1.08
sd
0.82
BLSD 0.94
6
5
4
3
2
n = 110
r = 0.82
1
1
2
3
4
5
Stewart's wilt ratings - 2001
6
7
465
R
x
S
12465
x
inbred
AAbbCC
x
aaBBcc
F1
Aa Bb Cc
F1
467
R
x
S
12467
x
inbred
AAbbCC
x
aaBBcc
Aa Bb Cc
F2 segregation
Freq.
Three resistance markers
A-bbC9
Two resistance markers
A-C27
bbC3
A-bb
3
One resistance marker
A9
bb
1
C9
No resistance markers
aaBBcc
3
Ratio (R:S)
%R
9:55
14
36:28
39:25
42:22
56
61
66
51:13
52:12
61:3
80
81
95
three
resistance
genes
A-bbC-
one
resistance
gene
two
resistance
genes
A-C-
bbC- A-bb
A-
bb
C-
Mean Stewart's wilt rating
5
4
3.79
3.21
3
3.37
4.16
4.22
aaB-C-
aaB-cc
3.92
3.48
2.66
2
1
A-bbC-
A-B-C-
aabbC-
A-bbcc
A-B-cc
Genotype
aabbcc
R x inbred testcross F2 segregation
Gene models
Ratio
Total (465 and 467) Obs
2 or 3 genes
Exp
465 x S inbred
Obs
2 or 3 genes*
Exp
*not A-bb or bbC467 x S inbred
2 or 3 genes**
** and A-
Obs
Exp
R
S
42:22
734
738.9
392
387.1
39:25
451
457.6
304
293.4
51:13
283
295.6
88
75.4
F2 segregation
Freq.
Three resistance markers
A-bbC9
Two resistance markers
A-C27
bbC3
A-bb
3
One resistance marker
A9
bb
1
C9
No resistance marker
aaBBcc
3
Ratio (R:S)
%R
9:55
14
36:28
39:25
42:22
56
61
66
51:13
52:12
61:3
80
81
95
90 S2 families - selected for Stewart’s resistance
90 S2 families - unselected
- looking for frequency of markers
bnlg 2248
Exp
67.5
Ha: selected
>67.5
bnlg 1902
22.5
>22.5
umc 1296
67.5
>67.5
Stewart’s resistance
from Bonus
• highly heritable
• appears to be associated with
three gene regions (2,5,6)
• one gene region (5) associated
with susceptibility
Why markers?
2
h
= 0.85
Many sources of resistance
Classical genetic studies
Wellhausen (1937) - OSF inbred - two major, one minor
Smith (1971) - K55, C123 - two dominant, independent
(one seedling, both leaf blight)
Parker (1993) - Pa419 - 1.1 to 4.1 effective factors
Molecular genetic studies
Ming (1999) - Ki14 - sw1 major gene
umc167, umc67 - chromosome 1
Brown (2001) - IL731a x W 6786 - three regions (4,5,6)