CORN INSECT MANAGEMENT Scott Stewart WTREC, Jackson, TN University of Tennessee Extension.
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Transcript of CORN INSECT MANAGEMENT Scott Stewart WTREC, Jackson, TN University of Tennessee Extension.
CORN INSECT MANAGEMENTScott Stewart
WTREC, Jackson, TN
University of Tennessee Extension
The Primary Issues
Seed treatments, at-planting insecticides A complex of soil insect pests
Managing non-Bt corn Primarily for corn borers
Bt corn technologies There are just so many options
Corn Seed Treatments (company offerings)
DeKalb (Monsanto) Pioneer Syngenta
AcceleronAcceleron +
Poncho/VOTiVOPPST 250
PPST 1250 + Poncho/VOTiV
O
CruiserMaxx Corn
Avicta Complete
Corn
Clothianidin*
(250 Rate)
Clothianidin(500 or 1250
Rate)
Thiamethoxam*
(250)
Thiamethoxam(250)
Thiamethoxam*
(250 Rate)
Thiamethoxam
(500 Rate)
Trifloxystrobin*
Trifloxystrobin*Azoxystrobi
n*Clothianidin
(1250)Azoxystrobi
n*Azoxystrobi
n
Metalaxyl* Metalaxyl*Fludioxonil
*Azoxystrobin
Fludioxonil*
Fludioxonil
Ipconazole* Ipconazole*Mefenoxam
*Fludioxonil
Mefenoxam*
Mefenoxam
Bacillus firmus(VOTiVO)
Thiabendazole*
MefenoxamThiabendaz
ole*Thiabendaz
ole
Thiabendazole Abamectin
Bacillus firmus(VOTiVO)
INSECT DISEASENEMATO
DE* Base treatments if premium seed treatments are not requested
Trade Name
Billbugs
White
grubsWire-
wormsSeedco
rn maggot
Cut-worm
s
Sugar-cane
beetleStink bugs
Chinch
bugs
Southern corn
rootworm
Poncho 250,
AcceleronP, NL F G E P - F F + F G E
Poncho 500,
Acceleron with
Poncho Votivo
F G G E P - F G F - G G - E E
Poncho 1250,
AcceleronG E E E F - G G G E E
Cruiser Extreme
250P, NL F G E P P P F G - E, NL
Cruiser Extreme
500, Avicta Complete
P, NL G G E P F F F E
Cruiser Extreme
1250G E E E F F G G E
Relative Efficacy of Corn IST
P = poor F = fair G = good E = excellent NL = not labeled
Corn At-planting Insecticides, Trial 12013, Tennessee
P250
P250
+ C
aptu
re
P250
+ C
aptu
re +
Sta
rter
P250
+ B
rigad
e
P250
+ B
rigad
e + S
tarte
r
P250
+ M
. Max
+ S
tarte
r
P500
+ S
tarte
r150
170
190
210
230 221.6 222.8218.6 217.4 219.0 219.6 222.5
Yield (B/A)
Corn At-planting Insecticides, Trial 22013, Tennessee
Untre
ated
Cruiser
500
Ponc
ho 5
00
Captu
re LFR
(4 o
z)
Count
er (6
.5 lb
)
Smar
tCho
ice
(5.5
lb)
Ponc
ho +
Cou
nter
Ponc
ho +
Sm
artC
hoice
150
160
170
180
190
200
210
184.2
202.9
195.0200.1 200.5 200.8
195.5 196.7
Yield (B/A)
Capture LFR In-furrow TrialStarkville, MS 2012 (Catchot)
154.2
149.4
145
138.5
130
135
140
145
150
155
160
Capture LFR 4 oz +Starter
Capture LFR 4 oz Starter Only Untreated
Bush
els/
Acre
aba bc c
All with Poncho 250
Managing Soil Insects
Be proactive in high risk fields New fields Problem fields
Cruiser or Poncho 250 not always enough 500 rates or higher In-furrow bifenthrin (Capture
LFR, Brigade, etc.)• Will also provide protection from
cutworms In-furrow granular insecticides*
* Be careful of insecticide/herbicide interactions
Corn Borers
The primary target of Bt corn Southwestern corn borer European corn borer
The second generations are typically the most destructive Because it is larger and
affects more acres
SWCB
ECB
V6 V14 R2 UNT V8 V14 R2 UNT0
20
40
60
80
100
120
140
160
180
200
Weig
ht
(g)
per
Ear
2010 2011
A
B
C
a
bb
A
a
Impact of Infestation Timing on YieldSWCB infested, non-Bt plants (Steckel and Stewart)
P < 0.0001
P < 0.0001
Infestation Timing
Treating non-Bt corn in the presence of high corn borer populations (Henry Co., TN)
No Inse
cticid
e
Hero (6
oz)
Belt SC (2
oz)5060708090
100110120130140
92
134
120
Yield (B/A) in 2010
No Inse
cticid
e
Disciplin
e (5 oz)
Belt SC (2
oz)50
70
90
110
130
150
170
190
210
148
194203
Yield (B/A) in 2011
Scouting Non-Bt Corn
Whorl stage Pretty easy Look for windowpane-like lesions on
emerging leaves Remove whorls and unfurl leaves to look
for small larvae that are present
Tasseling and later Much more difficult and requires
training
SWCB Moth Trapping
Triggers scouting or spray
SWCB Pheromone TrappingMoths/Trap/Week (Henry Co, TN, 2012)
6-May 16-May 26-May 5-Jun 15-Jun 25-Jun 5-Jul 15-Jul0
100
200
300
400
500
600
Henry (Puryear)
Action Thresholds
Scout / Spray Spray
No
New Southwestern Corn Borer Threshold (Non-Bt Corn)
Treat prior to tasseling when 5 percent or more of plants are found with egg masses or live larvae or 7-10 days after pheromone traps catch an
average of 50 or more moths on a 7 day catch
Beginning at tasseling (VT) and through the milk stage (R3), treat when 10 percent or more of plants are found with egg masses or live larvae or 7-10 days after pheromone traps catch an
average of 100 or more moths on a 7 day catch
Insecticide SelectionRefer to Local Extension Recommendations
First Generation (whorl) Many labeled
pyrethroid insecticides Baythroid XL Brigade (bifenthrin) Karate or Warrior II Mustang Max Etc.
Others as in tassel stage
Second Generation (tassel) Intrepid Belt SC Besiege Prevathon Tracer Pyrethroids as in
whorl stageDirect spray into whorls as much as possibleTypically requires aerial application
The Many Bt Corn Technologies
Bt corn is the primary means used to control corn borers
Many available Bt trait packages (old and new)
May or may not include Bt traits for western or northern corn rootworm
Trademarked Brands Corn borers Cutworm Corn
earwormFall
armyworm WCRW
YieldGard CB Excellent Poor Fair Fair None
Herculex Excellent Good Poor Good None
Herculex XTRA Excellent Good Poor Good Excellent
Agrisure CB/LL Excellent Poor Fair Fair None
Genuity VT Double Pro (VT2P) Excellent Poor Good Very Good None
Genuity VT Triple Pro (VT3P) Excellent Poor Good Very Good Excellent
Genuity or Dow AgroSciences SmartStax (GENSS or SSX) Excellent Good Good Very Good Excellent
Agrisure Viptera 3110 Excellent Good Excellent Excellent None
Agrisure Viptera 3111 Excellent Good Excellent Excellent Good
Optimum Intrasect Excellent Good Fair Very Good None
Optimum AcreMax Extra Excellent Good Fair Very Good Excellent
Relative Efficacy of Selected Bt Corn Traits
(see handout for more inclusive list & refuge requirements)
Cotton Counties
MISSOURI:Dunklin
New MadridPemiscot
ScottStoddard
Products with Bt rootworm traits require an “in-field” refuge
Non-Bt Corn Refuge Requirements
Cotton Counties 50% for the old technologies 20% for the new
VT2P, VT3P, SmartStax, Viptera, Optimum Intrasect, Optimum AcreMax
Corn Counties 20% for the old technologies 20, 10 or 5 % for the new
Refuge in bag (RIB) system for some
Do these refuge requirements make sense?For non-cotton growing areas !!!
5% Refuge of Non-Bt Corn
2+ caterpillar traits, 0 rootworm traitsVT2P, VT2P RIB, Optimum Intrasect,
Optimum AcreMax (RIB), and others
2+ caterpillar traits, 2+ rootworm traitsSmartStax or SmartStax RIB, Optimum
Acre XTreme (RIB), and others
Confirmed Resistance to Bt Traits
Fall armyworm to Cry 1F Herculex or Herculex Xtra Component of SmartStax, Optimum Intrasect
and Optimum AcreMax products
Western corn rootworm to Cry3 Bb1 VT3 and VT3P Component of SmartStax
Rotate fields to non-corn crops, rotate Bt rootworm traits, use at-planting insecticide and don’t use Bt rootworm traits if they are not needed
Close and
Major Pest
Far and
Minor
Pest
a
b
cccc
P < 0.0001 (LSD = 89.2)
Opt. In-trasect
Viptera Herculex YieldGard CB
NonBt 1 NonBt 20
50
100
150
200
250
300
350
400
450
All the Bt lep traits provide near perfect control of SWCB and ECB
SWCB and ECB InjuryCM Tunneling per 20 Stalks (TN, 2010)
Bt corn in the presence of corn borersYield (Milan, TN, 2011)
SmartStax Non-Bt120
125
130
135
140
145
150
155
160
155.4
132.5
a b
Bushels/Acre
Leaf Injury Score for FAW Catchot, 2010, Starkville, MS
9 8.7 8.7
7
2.7 2.7
0123456789
10
Leaf Injury Score (9-1 scale, 9 = no damage)
a a ba
c c
Vipte
ra
Opt
imum
Intras
ect
Her
cule
x
Corn EarwormThe most common ear feeding caterpillar
Non Bt
VT3
SmartStax(90%)
SmartStax Test - 2009
SmartStax Test - 2010
Non Bt
VT3P or SS(40%)
Approximate Reduction in Kernel Damage Compared with Non-Bt Corn
(Summarized Across Multiple University Trials, Corn Earworm)
Bt TraitsRange of Reduction
(%)
Average Reduction
(%)Herculex and HXX < 0 - 30 15
YieldGard, VT3, Optimum … 0 - 60 40
VT2Pro, VT3P, SmartStax 40 - 90 75
Viptera (VIP3A) 90 – 99 95
Viptera ... “outperforms triple stacks by 14.3 bu/A under significant corn earworm pressure and up to 32 bu/A under heavy pressure”
Reality Check
Yield of Top Ten Hybrids (Bu/Acre)2012 Tennessee Research & Education Center Tests (Allen, et al.)
Yield Early Maturity
Medium Maturity
Full Maturity
1 CB / RW HX / RW VT3P
2 CB / RW VT3P CB
3 VT3 VT3 HX
4 CB VT3P HX
5 VT2P VT3P VT3P
6 VT3P CB / RW VT3P
7 VIP CB Non- BT
8 VT3P CB CB / RW
9 VT3P VT3P VT3P
10 HX VT3P Non-Bt
Insecticide Trial on Non-Bt Corn Corn Earworm Injury and Yield (TN, 2011)
0
50
100
150
200
Kernel Damage per 10 Ears (prelim.)
Yield (B/A)
P(yield) = 0.9148
P(kernels) = 0.0013
Application at early silking (moderate pressure)
Insecticide Yield Effects on Non-Bt Corn(Tennessee, Stewart, 2012)
Prev
atho
n (8
)
Prev
atho
n (1
2)
Prev
atho
n (1
6)
Prev
atho
n (2
0)
Prev
. (12
) + A
s...
Asan
a XL
(8)
Belt
(2)
Intre
pid
(6)
Besieg
e (8
)
Untre
ated
100
110
120
130
140
150
160
147
137
151
130
142
136
142
153
138 139
Application at Early Silking (P = 0.568)
A lot of CEW but no treatment effects on kernel injury (P = 0.7341)
Simulated Corn Earworm Injury, Milk StageSteckel and Stewart, 2011
# Kernels Injured
# Kernels per Ear
Total Wt (g) per Ear
Wt (g) of Individual Kernels
0 592 a 165 a 0.2791c
30 560 b 162 a 0.2888 bc
60 507 c 149 b 0.2939 ab
120 477 d 143 b 0.3009 a
Spraying Corn for Corn Earworm
Foliar applications for ear stage infestations of corn earworm in field corn are not economically practical
No consistent yield response except in presence of southwestern corn borer
Expect little or no benefit on Bt corn (especially the newer traits) Exposure to insecticides without much yield reward May create secondary pest problems (spider mites)
Take Home About New Bt Corns
University data indicates that the new Bt corn traits will not improve yields in most cases compared with the original Bt technologies
Benefit of reduced refuge requirement Some potential for improved grain quality and reduced
mycotoxins … but not close to a silver bullet IRM ???
• Corn borers – expect multiple Bt toxins to delay resistance• Corn earworm – exposure to multiple Bt toxins without much
reward is concerning
Questions
War Eagle!
Aflatoxin Levels in Corn Roy Parker, Texas A&M University, 2011
DKC 6
8-04
(non
...
DKC 6
8-05
VT3
...
DKC 6
7-22
RR (n
...
DKC 6
7-21
VT3
...
P 33
F85
(non
Bt)
P 33
F87
HX1
Non B
tBt
11
Bt11
+MIR
162
(Vi..
.0
50
100
150
200
250
300
20.1
53.0
197.5
251.8
40.7
85.3
117.4
257.0
97.5
Test 1 Test 2
No statistically significant differences
Japanese Beetles
New Threshold: Treat when 3 or more beetles are present per ear
during the first week of silking.
Infestations are usually worse along
field margins.
Sugarcane Beetles
Final Kernel Damage(cm2/ear in center two rows of plot)
Pure s
tand
5% b
lend
10%
ble
nd
20%
ble
nd0
0.05
0.1
0.15
0.2
0.25 Chart Title
Pure s
tand
5% b
lend
10%
ble
nd
20%
ble
nd0
0.05
0.1
0.15
0.2
0.25 Chart Title
Early planting Late Planting
cm2
dam
ag
e
cm2
dam
ag
e
P = 0.0428, LSD(0.05) = 0.054, CV = 80.4P < 0.0045, LSD(0.05) = 0.094, CV = 61.9
bb
aa
b
bab
a
Grain yield (B/A)
Pure s
tand
5% b
lend
10%
ble
nd
20%
ble
nd100
120
140
160
180
200
162.4159.9 160.9
168.7
Chart Title
Pure s
tand
5% b
lend
10%
ble
nd
20%
ble
nd100
120
140
160
180
200187.9 186.3 188.1
184.1
Chart Title
Early planting Late Planting
bu/a
cre
bu/a
cre
P = 0.6860, LSD(0.05) = 8.5, CV = 2.8P = 0.6439, LSD(0.05) = 16.7, CV = 6.4
Simulated CEW Feeding (Blister)Steckel et al.
Simulated injury by ear-feeding larvae at the blister stage of corn on the number of kernels
per ear, kernel weight per ear and individual kernel weight, 2011.
No. of kernels targeted for injury
No. kernels per ear Total kernel wt (g) Individual kernel wt (g)
0 564.9a 155.2a 0.2744c
30 553.3ab 157.2a 0.2841bc
60 524.8bc 151.2a 0.2880ab
120 514.3c 153.9a 0.2992a
P > F 0.0031 0.7400 0.0007
Means not followed by a common letter are significantly different (Proc MIXED, P < 0.05)
Tennessee - Corn Isolines ComparisonsImpact of New Bt Technologies (VT3 Pro, SmartStax, Viptera)
Yield (B/A)
Location & Year Non-Bt YG or VT3 VT3 Pro or SS
TN – 2007 213 257 242
TN – 2008 207 ---- (207) 233 *
TN – 2009 114 150 127 *TN – 2009 (demo) 144 126 149
TN – 2009 194 206 199
TN – 2010 (early) 147 152 147
TN – 2010 (late) 154 160 160
Average 167.6 179.7 179.5
Location & Year Non-Bt Bt11 Viptera
TN – 2009 135 163 151
TN – 2011 147 172 171
* Average of 3 (2008) or 2 hybrids (2009) that were VT Pro or SmartStax
Yield of Selected Seed Trt’s and In-Furrow Combinations (MS, Catchot)
100
120
140
160
180179 177
167 163 162 162 159 153145 143
Yield
Non-Bt Corn Insecticide TestModerate infestations of SWCB (Application July 16, 2008)
105
126
147
128
0
20
40
60
80
100
120
140
160
SWCB Girdles/360 Row Ft Bushels/A
a
ab b
c
b b
a
Planted May 1