On-farm trials – 2018Thanks to Jeremy Hebert and Boyd Padgett
Effect of commercial fungicide application on aerial blight and yield –QoI–resistant location, 2016.
aab
cd
cd
d
0
20
40
60
80
100
120
0
50
100
150
200
Yie
ld (
g/1
0 p
lts)
Dis
eas
e S
eve
rity
(A
UD
PC
)
Aerial blight
Yield (g/10 plants)
MROS1601
R2 Application Timing
Cercospora leaf blight – Acadia
Pod and stem blight and seed quality – Acadia
*
* *
*
** *
*
0
1
2
3
4
5
6
7
8
9
Dis
eas
e S
eve
rity
(0
-9)
CLB (0-9) 9/12
PSB (0-9) 9/12
OSSB1801-F1
Fungicide Efficacy on CLB and PSB – Acadia 1
R4 and R5.5 application timing
*
*
**
** *
*
0
1
2
3
4
5
6
7
8
9
Dis
eas
e S
eve
rity
(0
-9)
CLB (0-9) 9/12
PSB (0-9) 9/12
Seed Quality (0-5) 10/1
OSSB1801-F2
Fungicide Efficacy on CLB, PSB, and seed quality – Acadia 2
R4 and R5.5 application timing
NONTREATED VS TREATED – 2017, Winnsboro, LA
Cercospora leaf blight trial – Winnsboro, LA – 2017
Cercospora leaf blight trials – 2017
*
*
**
*
* *
0
5
10
15
20
25
30
35
40
45
50
0
1
2
3
4
5
6
7
8
9
10
Yie
ld (
bu
/A)
AG
58
31
Dis
eas
e S
eve
rity
(0
-9)
Phytotoxicity (0-9) 8/21
Cercospora leaf blight (0-9)9/11
MRSB1813
Multiple programs – Winnsboro, LA – 2018
**
**
*
0
1
2
3
4
5
6
7
Dis
eas
e S
eve
rity
(0
-9)
Cercospora leaf blight (0-9)10/4Cercospora leaf blight (0-9)10/11
DLSB1808
Multiple programs – Alexandria, LA – 2018
* *
*
*
* *
*
*
0
1
2
3
4
5
6
7
Dis
eas
e S
eve
rity
(0
-9)
Cercospora leaf blight (0-9)10/4Cercospora leaf blight (0-9)10/11
DLSB1806
Promising Experimentals – Alexandria, LA – 2018
Products that have somewhat consistent efficacy on CLB in the past few years
• Domark
• Miravis
• Priaxor
• Quadris Top SBX
• Topguard
• TrivaPro
• Possible reasons…• Genetic diversity in
pathogens• Ratio of pathogens in a given
area• Varying degrees of fungicide
resistance across areas• Differences in varietal
responses to disease and/or fungicide application
• Combinations of all of the above
NO GUARANTEES
Official Variety Trials
www.lsuagcenter.com/topics/crops/soybeans/
Variety Development
St. James Parish, LA – 2018
NT
NT
NT
Thanks to Al Orgeron and Boyd Padgett
Target spot vs. CLB
a
ab
ab
ab
b
ab
ab abab ab
a
b
40
45
50
55
60
65
70
75
80
0
1
2
3
4
5
6
7
8
9
Yie
ld (
bu
/A)
Dis
eas
e S
eve
rity
(0
-9)
CLB (0-9) 7/31 Target spot (0-9)7/31 Yield (bu/A)
St. James
St. James – Fungicide efficacy on CLB and target spot
Target spot trial – Winnsboro, LA – 2018
*
*
0
5
10
15
20
25
30
35
40
45
50
0
0.5
1
1.5
2
2.5
3
3.5
4
Yie
ld (
bu
/A)
Dis
eas
e S
eve
rity
(0
-9)
Target spot (0-9) 8/21
Yield (bu/A)
MRSB1808
Target spot trial – Winnsboro, LA – 2018
Frogeye leaf spot
Frogeye Leaf Spot – Fungicide Resistance
Strobilurin resistance confirmed in 36 parishes
Suspect that the majority (>90%) of the pathogen population is resistant
Regional Frogeye leafspot trial – Alexandria 2016.
ab
abc
d
a-d
ab
a
ab
ab
ab
bcd
cd
abc abc
0
10
20
30
40
50
60
70
80
90
0
10
20
30
40
50
60
Dis
eas
e S
eve
rity
(A
UD
PC
)
Yie
ld (
bu
/A)
AG
49
34
Frogeye leaf spot Yield (bu/A)
DLSB1603
Salt Tolerance Ratings – Winnsboro, LA
MRRS OVT – 2016 – Seed Quality
Purple Stain % Damage
Seed Treatment Fungicides• CDMS website: www.cdms.net
• Agrian website: www.agrian.com
• ~80 seed treatment or in-furrow fungicides labeled in soybean
• http://www.lsuagcenter.com/portals/communications/publications/management_guides
Soybean Seed Treatment Advice
• Do your homework…figure out which fungicides are already on the seed…may vary with company.
• “Base” fungicides usually consist of metalaxyl/mefenoxam+broad spectrum QoI/DMI
• Base treatments are adequate in soybean• It is redundant to over-treat with the same MOA• Fungicides are not needed with optimum conditions• Even “Cadillac” treatments fail under worst case
scenarios• Seed supply is an issue this year…
TAPROOT DECLINEFIRST REPORT – AR, AL, LA, & MS - 2017
AllenBluhmConnerDoylePriceSikoraSinghSpurlockTomaso-PetersonWilkerson
Plant Health Progress. 2017. 18:35-40
https://apsjournals.apsnet.org/doi/10.1094/PHP-01-17-0004-RS
Phylogenetic Characterization
Distribution of the pathogen• Taproot decline has been reported in
AR, AL, LA, MS, and TN
• MO? IL? IN? KY? GA? FL?
T. G. Garcia Aroca
NoPhylogeographic
Structure
Low genetic diversity = “recent” introduction
Isolates of the TRD pathogen do not cluster genetically by region.
All closely related…
What is Xylaria???
• Vague report of Xylaria on soybean seed, 1979
• Known saprophytes (wood rotters)
• Few pathogenic: X. mali (apple) and X. acuta (cherry)
• Some species are endophytes (friendly fungi)
Symptoms
Control Colletotrichum sp.
Xylaria sp.
Isolate 1 Isolate 2 Isolate 3
Non-pathogenic Pathogenic
Mycotoxins (presumably) produced by Xylaria (TRD) isolates reproduce the symptoms observed in the field.
Doyle and Garcia, LSU AgCenter
Symptoms
Taproot decline also is a seedling disease…
Root Symptoms
Make visual aid for planting
• Soybean monoculture
• Reduced tillage
• Debris accumulation
• Super accurate planting
YOU ARE AT RISK!!!
Taproot decline can cause serious yield losses…
Dr. Terry Spurlock, University of Arkansas, 2018
Aerial Imagery and Yield (MS)
Spurlock & Allen
On-farm yield loss estimates
On-farm yield loss estimates
R2=0.5720P=<0.0001
• Disease loss estimates available in March 2019 for all affected states.• In Louisiana, losses have ranged from 700K-3.5M bu annually since 2014.
a
b
e
de
a
cd
a a
c
ab
0
20
40
60
80
100
120
Mertect0.16 floz/cwt
InoculatedCheck
Topsin-M0.28 mgai/seed
Maxim 0.16fl oz/cwt
Vibrance0.16 floz/cwt
AvictaComplete
6.2 floz/cwt
Apron XL0.64 floz/cwt
Ilevo0.25 mgai/cwt
CruiserMaxx2.95 floz/cwt
Quadris0.19 floz/cwt
% Xylaria-diseased Seed
P=0.01LAB STUDY, Dr. Terry Spurlock
0
20
40
60
80
100
120
Inoculated Check Topsin-M 0.15 mgai/seed
Mertect 0.16 fl oz/cwt Topsin-M 0.075 mgai/seed
Mertect 0.32 fl oz/cwt
% Xylaria-diseased Seed
a
c
b
c
bc
P=0.01LAB STUDY, Dr. Terry Spurlock
aba
abab
a
bc
c
d
d
aab
d
0.0
10.0
20.0
30.0
40.0
50.0
60.0
% Y
ield
Re
du
ctio
n
Variety Screeningwww.louisianacrops.com
% R
oo
t R
ed
uct
ion
Variety
Susceptible
In the middle
Resistant
Resistant varieties (<24% root reduction)
Variety % Root Weight Reduction
OSAGE 8.391702
CZ 4818LL 18.879462
5N490R2 19.263012
S42RY77 20.944016
5N433R2 22.215409
5067 LL 22.559704
R07-6614RR 22.970824
MR varieties (24-36% root reduction)Variety % Root Weight Reduction
Armor 55-R68 25.253945
RJS47016R 25.793535
CZ 5375RY 26.205598
HBKLL4953 27.339808
4880 RR 27.926596
P5752RY 28.094408
CZ 5225LL 28.605468
ARX4906 29.805397
Go Soy IREANE 30.762175
4995 RR 30.883269
AG 48X7 31.611326
P4788RY 32.46393
AG 46X6 34.502577
S47RY13 35.157094
5625 RR2 35.190462
S49XT07 35.483918
Field Confirmation
Bad luck…
• Complicating factors (natural infection, herbicide damage, chloride toxicity, drought)
Good news…
• Inoculum works
• Height and Yield differences
• All varieties that showed significant height reduction in the field were SUSCEPTIBLE in greenhouse studies
• Varieties deemed RESISTANT in the greenhouse had no significant height reduction in the field
More work is needed…
a
b
b
0
2
4
6
8
10
TRD
Inci
de
nce
(%
)
TRD Incidence (%)
MRTP1102
Year Treatment 1 Treatment 2 Treatment 3 Treatment 4
2016 SB SB SB SB
2017 SB SB SB SB
2018 SB CN GS CT
2019 SB SB SB SB
Southern RKN
2018 soybean root-knot
nematode variety and
nematicide trials
Keo silt loam (58-40-2 =
% sand – silt – clay)
% Root system galled
MG IV soybean cultivars (RR & Xtend) in southern RKNfield near Kerr (2018)
38 10
3 5
3632
79 80 81
7073
53
87 87
99
8994 97
84
98 95 96 99 96 96 99
68
59 57 56 5652
50 4843 42 42 41 41
3128 27
2421 21 19
16 15 15 14 12 11 9
0
10
20
30
40
50
60
70
80
90
100
Galled Root system (%) Yield (bu/A)
Pi = 60 and Pf = 369 J2/100 cm3
Susceptible Check
Dr. Travis Faske
MG V soybean cultivars (RR and Xtend) in southern RKNfield near Kerr (2018)
20 19
713
814 15
4 49
4 7 38
77
93 95 96
80 78 77 77 75 75 75 75 74 73 72 71 70
60
3428
1811
0
20
40
60
80
100
120
Galled Root system (%) Yield (bu/A)
Pi = 40 and Pf = 395 J2/100 cm3
Susceptible Check
Overall, these
MG V yield
better in a RKN
field (+15 bu/A =
25% increase)
Dr. Travis Faske
Liberty Link
MG IV
• Resistant
• Pioneer 45A29L
• MR
• Delta Grow 4977LL/STS
• Dyna Gro S49LS65
MG V
• MR
• Pioneer P52A43L
• Terral REV 54L18
Dr. Travis Faske
Soybean Varity Response to RKN is on the www.arkansascrops.com website
Dr. Travis Faske
Thank YOU for Supporting Us!
Louisiana Soybean and Grains Research and Promotion Board
ProducersAgentsConsultantsIndustry
Trey [email protected]@ppp_trey
Boyd PadgettBrenda TubanaBrian WardDan FrommeDaniel StephensonDarrell Franks and CrewDonnie MillerJohn RocconiJosh CopesMyra PurvisRick MascagniScott Washam and CrewSebe BrownSteve HarrisonTeddy GarciaVinson DoyleWarren Ratcliff and Crew
Rotation with a non-host crop
Southern root-knot nematode
(Meloidogyne incognita)
Reniform nematode
(Rotylenchulus reniformis)
XXXX
X X
Soybean cyst nematode
(Heterodera glycines) X
Soil- and seed-applied nematicides registered for use in soybean
Soybean
Nematicides
Fumigants Injected, preplant
TeloneII,Vapam, and
K-Pam
Non-fumigantsSeed-applied, at
planting
Avicta, ILeVO, NemaStrike,
VOTiVO, BioST, Aveo
EZ,, Clariva pn
Trade Name Active Ingredient Mode of Action Signal
Word
Avicta Abamectin Inhibit nerve transmission Danger
ILeVO Fluopyram SDHI enzyme inhibitor Caution
NemaStrike ST Tioxazafen Mitochondrial translation
inhibitor
Caution
Soil- and seed-applied nematicides registered for use in soybean
Soybean
Nematicides
Fumigants Injected, preplant
TeloneII,Vapam, and
K-Pam
Non-fumigantsSeed-applied, at
planting
Avicta, ILeVO, NemaStrike,
VOTiVO, BioST, Aveo
EZ,, Clariva pn
Trade Name Active Ingredient Mode of Action Signal
Word
Avicta Abamectin Inhibit nerve transmission Danger
ILeVO Fluopyram SDHI enzyme inhibitor Caution
NemaStrike ST Tioxazafen Mitochondrial translation
inhibitor
Caution
VOTiVO Bacillus firmus I-1582 Repels nema and affects
motility
Caution
BioST Nematicide
100
Burkholderia rinojensis
A496
?? Caution
AVEO EZ
Nematicide
B. amyloliquefaciens
PTA-4838
?? Caution
Clariva pn Pasteuria nischizawae Parasite to SCN only Caution
2018 seed-applied nematicides trial (Kerr field)
36.8
34.1
40.0
34.5
38.8 39.7
32.6
0
5
10
15
20
25
30
35
40
45 Percent Root System Galled Yield (bu/A)
Galling P > F= 0.54
Yield P > F = 0.03
Delta Grow DG 4970
Planted May 29, 2018
ab ab b ab ab a b
Different letters on bars indicant a significant difference at α = 0.10 according to Tukey’s HSD test
Pi = 32 and Pf = 308 J2/100 cm3 soil
2018 seed-applied nematicide trial (Kerr field)
27.3
30.5
26.9
35.7
30.131 31.1
28.7
19.918.7
19.921.2
23.224.7
26.1
23.1
0
5
10
15
20
25
30
35
40 % root galling Yield (bu/A)
ab a ab abc bc c c abc
• Galling (P = 0.72)
– AG42x6 = 30.4%
– AG51x6 = 30.0%
• Yield (P = 0.68)
– AG42x6 = 21.8 bu/A
– AG51x8 = 22.4 bu/A
Different letters on bars indicant a significant difference at α = 0.10 according to Fishers LSD
Galling P > F= 0.11
Yield P > F = 0.085 Pi = 221 and Pf = 368 J2/100 cm3 soil
Potential reproduction of M. incognita
on seven cover crops
4.8 5.4
14.9 15.1
50.9
61.1
75.8
0
10
20
30
40
50
60
70
80
Black-hulled
Oats
Bayou Kale Cereal Rye Crimson
Clover
Turnip Austrian
Winter Pea
Barley
Rep
rod
uct
ion f
acto
r (P
f/P
i)
Each pot was inoculated with 6,000 eggs
Small seeded dicots planted earlier for similar root size
Harvested 60 days after inoculation
a a ab ab bc c c
Letters on bars indicate a significant difference at α = 0.05 according to Tukey’s HSD
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