Soybean Aphid Wisconsin 2003 Recap

Eileen Cullen

University of Wisconsin Extension Entomology Department

Latitude Bridge Illinois – Iowa – Minnesota - Wisconsin February 5th, 2004

Wisconsin Recap 2003

State Soybean Aphid Survey Dynamic Threshold Concept Role of Insecticides Treatment Decision Dynamics Additional (Evolving) Tactics

Eileen Cullen – UW Extension, Entomology

Summary

 19% of sites with 201-500 aphids/plant  20% of sites with 501-1000 aphids/plant  16% of sites with 1001-2000 aphids/plant  11% of sites with 2000 + aphids/plant

Courtesy of

Krista Lambrecht, WI DATCP

District Averages

Northwest

566

North Central

93

Northeast

170

Statewide Average

West Central

633

Central

680

East Central

994

Southwest

149 1006

South Central Southeast

1268 

770 aphids/plant

Number of Soybean Aphids per Plant

Courtesy of

Krista Lambrecht, WI DATCP

Direct and Indirect Effects on Yield

Soybean aphids feed on plant sap Reduces # beans per pod Reduces bean size Reduced # flowers Photo © Iowa State University Changes bean quality Virus Transmission

Economic Injury Level

= Pest density which causes loss equal to the cost of control.

Economic Threshold

= Pest density at which control action is taken to PREVENT pest population from reaching or exceeding the EIL Soybean aphid Exponential Growth Soybean Varietal Tolerance to SBA?

Drought Stress!

Direct Yield Loss Soybean Aphid Threshold Indirect Yield Loss Cost of Control Potassium Levels Crop Stage Expected price of crop Soybean Yield Response to Insecticide Treatment Biological Control & Abiotic Factors

Eileen Cullen – UW Extension, Entomology

Yield Response by Spray Date

31 on-farm strip trials from WI 2003

July 23 – August 11 Applications 17.5

Avg. Yield Advantage = 7.1 Bu/A

15.5

13.5

11.5

Yield Difference

9.5

Bu/A

7.5

5.5

3.5

1.5

-0.5

22-Jul 27-Jul Yield Diff (Bu/A) 1-Aug

Spray Date

6-Aug 11-Aug

Eileen Cullen – UW Extension, Entomology

Pyrethroid

Labels for Soybean Aphid

Trade Name Asana * Active Ingredient esfenvalerate Rate/Acre (fl. oz.) 5.8 to 9.6

REI (Hours) 12 PHI (Days) 21 Baythroid ** cyfluthrin 2.8 fl. oz.

Mustang Max zeta cypermethrin Warrior Pounce * lambda cyhalothrin permethrin 2.8 to 4.0 1.92 to 3.2

4.0 to 8.0

*

2(ee) Label

**

Labeled for soybean aphid

Suppression

12 12 24 12 45 (15 green forage) 21 45 60

Eileen Cullen – UW Extension, Entomology

Organophosphate

Labels for Soybean Aphid Trade Name Dimate 4EC * Dimethoate 4E * Lorsban 4E Penncap-M

*

2(ee) Label Active Ingredient dimethoate Rate/Acre (pint/A) ½ to ¾ REI 48 hrs PHI (Days) 21 chlorpyrifos methyl-parathion 1 to 2 24 hrs 28 1 to 3 4 days * 5 days ** 20 * avg. annual rainfall = or > than 25” ** avg. annual rainfall < 25”

Eileen Cullen – UW Extension, Entomology

Carbamate

Label for Soybean Aphid Trade Name Furadan 4F Active Ingredient carbofuran Rate/Acre (pint/A) ¼ to ½ REI PHI (Days) 48 21

Eileen Cullen – UW Extension, Entomology

Product Performance &

Canopy Distribution

Lorsban Furadan Pyrethroids

Volatile distribution through canopy.

May “fume” into untreated check strips Systemic, a.i. activity

within

plant in addition to contact activity Cannot work its way through canopy beyond contact activity.

Coverage

in closed canopy inner locations on plant.

critical for efficacy against aphids at lower and

Eileen Cullen – UW Extension, Entomology

Product Performance &

Temperature

Lorsban Furadan

Optimal performance at higher temps.

(may increase “fuming” action) Also relatively better at higher temp

Pyrethroids

Exhibits a Negative Temp Relationship: Works better under cool conditions below 90 o F.

Eileen Cullen – UW Extension, Entomology

Product Performance &

Residual

Lorsban Furadan Pyrethroids

Short residual, measured in days.

Longer residual than organophosphates.

Some additional feeding exposure, due to systemic activity Longest residual , 2 weeks or more

Eileen Cullen – UW Extension, Entomology

Watch Late-Planted Fields

 Plants relatively younger, more nitrogen (?)  Soybeans in critical bloom/reproductive stages at aphid build

400 Aphids on Youngest Trifoliate 300 200 100 9-May 29-May 7-Jun 0 7/ 5/ 20 01 7/ 12 /2 00 1 7/ 19 /2 00 1 7/ 26 /2 00 1 8/ 2/ 20 01 8/ 9/ 20 01 8/ 16 /2 00 1 8/ 23 /2 00 1 Sampling Date

Data Courtesy of Craig Grau, UW Plant Pathology

Biotic and Abiotic Dynamics!

Relatively Cool Summer 2003 Optimal temperature for soybean aphid development: 68 to 77 ° F Biological Control Soybean aphid predators function better at high temperatures Weather Fungal disease: prolonged hot and humid conditions Drought, Scattered Rainfall Heavy rainfall can temporarily reduce aphid populations – depending on canopy density.

Eileen Cullen – UW Extension, Entomology

Natural Enemy “Lag” Time

Spray Timing Critical – Aphid Resurgence Factor 1600 1400 1200 1000 800 600 400 200 0 7/11 soybean aphid Harmonia Orius Lacewing Nabis 7/18 7/25 100 80 60 40 20 8/1 8/8 8/17 8/24 8/29 9/5 0

Bob Ellingson and David Hogg, UW Entomology

Photo Courtesy of Lisa Behnken U of MN, Extension

Winged Aphids

Efficient Virus Vectors

Alfalfa Mosaic Virus Soybean Mosaic Virus Cucumber Mosaic Virus Snap Beans

Foliar symptoms of virus

Yellow chlorotic leaf patterns Crinkled, “drawstring” leaflets

No Thresholds for Virus

Eileen Cullen – UW Extension, Entomology

Soybean Aphid – Interaction with other Stresses

Drought Stress Potassium Deficiency Multiple Pest complex

-Bean Leaf Beetle -BLB transmitted virus BPMV -Planting Dates: late plant against BLB/BPMV early plant less aphid trouble

Eileen Cullen – UW Extension, Entomology

Soybean Genetics Breeding lines differ for population density and symptom severity

Aphid Colonization of Different Soybean Lines

2000 1800 1600 1400 1200 1000 800 600 400 200 0 153.282

Spansoy250 BSR101 90573 AR16 M94-209136 6/20 6/30 7/9 7/15 7/21 7/28 8/4 8/11 8/19 8/25

Craig Grau et al.– UW Extension, Plant Pathology

Soybean Genetics Yield Response to Insecticide – Breeding Line Differences

Effects of Soybean Aphid on Yield

60 50

57

Insecticide spray No spray

44 42

40

30 34 32 33 34

30

Yield Bu/a

20

27 21 21 24

10 0

AR16 90573 BSR101 153.282

Soybean Lines Span250 M94-209136

Craig Grau et al.– UW Extension, Plant Pathology

Role of Insecticides: Insecticides timed properly on the basis of scouting Reduce aphid populations and plant stress quickly Scouting Threshold Optimal Timing Evolving Approaches and Correlations: Varietal Resistance/Tolerance Biological Control Nicotinoid Insecticide Seed Treatment Moisture Stress Potassium Level

Eileen Cullen – UW Extension, Entomology

Soybean Aphid Efficacy Data & Threshold Guidelines

Eileen Cullen

University of Wisconsin Extension Entomology Department

Latitude Bridge Illinois – Iowa – Minnesota - Wisconsin February 5th, 2004

Efficacy Data & Management Guidelines Nicotinoid Seed Applied Insecticides on Soybean WI 2003 Efficacy Data:



Foliar Residual Activity



Seed Treatments 2004 Scouting &Threshold Guidelines

Eileen Cullen – UW Extension, Entomology

Nicotinoid Insecticide Seed Treatment

How does it work in the plant?

Systemic.

As the seed imbibes water and germinates, a.i. on the seed is taken up into plant through the xylem.

Nicotinoid Class: a.i. ~ clothianidin [Poncho] a.i. ~ imidacloprid [Gaucho] a.i. ~ thiamethoxam [Cruiser]

Eileen Cullen – UW Extension, Entomology

Graphic courtesy of Karen Arthur, Gustafson LLC

Nicotinoid Insecticide Seed Treatment

How does it work in the insect?

Sodium Channel: Pyrethroids Pre-synapse Synaptic Cleft Post-synapse Acetylcholine esterase: OP’s, Carbamates Acetylcholine receptor: Neonicotinoids

Graphic courtesy of Karen Arthur, Gustafson LLC

Nicotinoid Seed Treatment

Soybean

–

In Trial Phase



Soybeans treated on a grams a.i. per 100 Kg seed basis.

“Poncho 62.5” =

62.5 g a.i. / 100 Kg seed 

Early season protection

. Interest in how long into season activity persists.

(4 – 6 + weeks depending on a.i., crop, and pest)

Eileen Cullen – UW Extension, Entomology



Selective activity

against piercing-sucking insect feeding and virus transmission.

 Reduced non-target effects 

Nicotinoid Resistance Concerns

Imidacloprid – clothianidin - thiamethoxam    Field Corn corn rootworm Field Corn 2 ° soil pests YieldGard Rootworm Bt Field Corn seed protectant   Seed and Food Grade Soybeans Grain Soybeans (registration in development phase)

Eileen Cullen – UW Extension, Entomology

Soybean Aphid Insecticide Trials Arlington, WI 2003

 Foliar Trial (pyrethroids ,organophospates)  Nicotinoid Seed Treatment Trials ~ clothianidin [Poncho] ~ imidacloprid [Gaucho] ~ thiamethoxam [Cruiser]

Eileen Cullen – UW Extension, Entomology

Soybean aphid FOLIAR trial. Arlington, WI Mean Aphids/Plant 4d, 1wk and 2 wks post treat.

Treated 7/31 at R2 (500+ aphids/plant) Treatment

Untreated Warrior 1CS 3.84 oz.

dimethoate 1 pt.

Baythroid 2.8 oz.

Mustang Max 4.0 oz.

Mustang Max + NIS Asana 6.4 oz.

Asana 9.6 oz.

Lorsban 4E 2.0 pt.

4 days

996.5

a

26.3

f

36.2

e

181.5 d 203.2 d 353.9

b

330.4

b

204.6

c

0.5

g 1 week 2 weeks

1518.8

a

22.2

e

45.5

d

344.5

b

200.3

c

437.1

b

346.5

b

368.3

b

15.3

e

1823.5

a

72.6 e 147.0 c 476.0

b

307.8 c 440.6

b

349.3 b 168.9

c

91.9

d Mean yields (bu/A) within a column followed by a different letter are significantly different at



= 0.05 (Fishers exact test)

Eileen Cullen – UW Extension, Entomology

Seed Treatment Trial

Soybean Aphid

Trial 1

Planted: June 9 Harvest: Oct 16 Cultivar: NK S19-V2

Trial 2

Planted: June 9 Harvest: Oct 16 Cultivar: NK S24-K4 Plots: 10’ w x 25’ l CRBD: 4 replicates Poncho 62.5

Poncho 125 Gaucho 62.5

Cruiser 62.5

CHECK Plots: 10’ x 25’ l CRBD: 4 replicates Cruiser 30 Cruiser 50 Gaucho 62.5

CHECK

Eileen Cullen – UW Extension, Entomology

3500 3000 2500 Aphids/ plant 2000 1500 1000

250

500

Aphids/Plant

0

Soybean Aphid Seed Treatment Trial 1, Arlington WI 2003 Mean Aphids/Plant by sampling date

Untreated Poncho 62.5

Poncho 125 Gaucho 62.5

Cruiser 62.5

8-Jul 16-Jul 22-Jul 30-Jul

Sample Date

4-Aug 13-Aug

Eileen Cullen – UW Extension, Entomology

Soybean [aphid] seed treatment trial 1, Arlington WI 2003 Yield (bu/A) by Treatment .

(

P

= 0.1151; F = 2.33; df, 4)

Treatment

Untreated Poncho 62.5

Poncho 125 Gaucho 62.5

Cruiser 62.5

Yield (bu/A)

38.1 b 42.2 a b 44.3 a b 43.2 a b 52.8 a Means followed a different letter are significantly different at  = 0.05

Eileen Cullen – UW Extension, Entomology

2500 Soybean Aphid Seed Treatment Trial 2, Arlington WI 2003 Mean Aphids/Plant by sampling date 2000

Untreated Cruiser 30 Cruiser 50 Gaucho 62.5

Aphids/ plant 1500 1000 250 500 Aphids/Plant 0 8-Jul 16-Jul 22-Jul 30-Jul Sample Date 4-Aug 13-Aug

Eileen Cullen – UW Extension, Entomology

Soybean [aphid] seed treatment trial 2, Arlington WI 2003 Yield (bu/A) by Treatment.

(P = 0.002; F = 6.59; df, 5)

Treatment

Untreated Cruiser 30 Cruiser 50 Gaucho 62.5

Yield (bu/A)

38.1

c

43.6 b

c

49.7

a

b 41.3

b c

Means followed a different letter are significantly different at  = 0.05

Eileen Cullen – UW Extension, Entomology

Seed Treatment Summary



Seed treatment trials were LATE planted (June 9).

 Seed treatment for soybean aphid will need to take planting date into account to ensure systemic activity during aphid impact.

Eileen Cullen – UW Extension, Entomology

EPA Section 18 Emergency Exemption Registration in WI and IA ( March 28 to June 1, 2003 ) for Gaucho on seed and food grade soybean only. Labeled for early season Bean Leaf Beetle and Bean Pod Mottle Virus control.

Gustafson has been contacted by the state of IA with plans to request another Section 18 for Gaucho seed treatment 2004.

Early season Bean Leaf Beetle control and Soybean Aphid. May cover all soybeans.

Soybeans are treated by the manufacturer or seed dealer state(s) with the Section 18 registration.

, NOT on-farm by producer. Soybeans may only be treated in [2003: 400,000 Acres worth of seed/food-grade beans could be treated in IA and WI, then planted in other states].

Eileen Cullen – UW Extension, Entomology

Consensus Recommendations for 2004 Phil Glogoza ND State Tom Hunt Univ of Nebraska Ragsdale, Ostlie, et al.

U of Minn Eileen Cullen U of WI Cooperating Entomologists/ Universities Marlin Rice Iowa State Wayne Bailey U of MO Voegtlin Steffey Gray U of IL Chris DiFonzo MSU Larry Bledsoe Purdue Hammond, Eisley OSU

Chris DiFonzo, Michigan State University

Threshold

- 250 aphids per plant - assumes aphid numbers are on the increase provides a 7-day lead time (call in equipment, deal with weather delays) - use through R4 (full-pod stage) Cannot overemphasize DROUGHT

Chris DiFonzo, Michigan State University

Temp

68 o F 77 o F 86 o F 95 o F

Life span (days)

22 15 12 3 (die) How fast can a soybean aphid reproduce?

[data generated in the lab by Ragsdale et al., Univ. of Minnesota]

First babies (# days)

7

Total # babies

75

Doubling time (days)

2 5 5 - 73 23 1.5

2 0 dead

Chris DiFonzo, Michigan State University

How much yield (# bushels) must be lost from aphid damage to equal a control cost of $12.00/ acre?

Price $/bu $5.00

# bu 2.4

$6.00

2.0

% of Yield potential, bu/acre 60 4.0% 3.3% 50 4.8% 4.0% 40 6.0% 5.0% $7.00

1.7

2.8% 3.4% 4.2%

[Based on data from University of Minnesota plots in 2003] Chris DiFonzo, Michigan State University

How many aphids per plant cause that much yield loss…..

+

a 7-day lead time?

Price $/bu $5.00

# bu 2.4

% of Yield potential, bu/acre 60 4.0% 254 50 4.8% 305 40 6.0% 381 $6.00

2.0

3.3% 210 4.0% 254 5.0% 317 $7.00

1.7

2.8% 178 3.4% 216 4.2% 270

[Based on data from University of Minnesota plots in 2003] Chris DiFonzo, Michigan State University

When:

Scouting

begin late June/ early July (may vary by region) What: Whole plant counts - 20 to 30 plants per field - no apparent edge effects (winged aphids colonize uniformly) - increasing populations even out across plants Pay special attention to: areas w/ buckthorn (colonized early) - late-planted fields - double-cropped beans - beans under stress, particularly DROUGHT STRESS How many times?

Fields have to be visited multiple times How Long?

2003, up to third week of August in many locations.

Chris DiFonzo, Michigan State University

Timing of Application

Continue to scout and work from 250/plant as a reference threshold 250 aphids per plant - Increase threshold.

- Yield benefit may be less.

Do Not treat Late Veg stages

R1 – R2 bloom R3-R4 pods forming, growing R5 seeds forming’ filling R6 full seed R7 matur ing R8 mature

Chris DiFonzo, Michigan State University

Will 2004 be a repeat of 2003?

What is the Soybean Aphid “Norm”?

Prepare with Guidelines Presented Here:

Scouting Use of Threshold Optimal Spray Timing

Watch for state-specific information in your summer newsletters.

Wisconsin Crop Manager: http://ipcm.wisc.edu/wcm/