soybean aphid efficacy program update 2011 icm conference, ames iowa update on the soybean aphid...

Soybean aphid efficacy program update2011 ICM Conference, Ames Iowa

Update on the soybean aphid efficacy program

Erin Hodgson and Greg VanNostrandDepartment of Entomology


Outline

• Review of survey to Iowa soybean growers in 2010

• Soybean aphid efficacy evaluation

• Where to get more info, handouts


Background…

• In 2010, paper survey mailed to every ISA member (4,908)

• 18.5% response rate (903); 24% ac grown

• ?’s about production, pests, information sources


Survey Goals…

• Encouraged to conduct needs-assessment to stakeholders

• Grower awareness of primary soybean pests• How often are they scouting?• How many acres are being treated with

insecticides?• Where are they getting management info?


A decade of changes

• Few economic soybean pests

• Soybean aphid confirmed in 2000– 40% economic loss potential– Quickly became #1 pest– Production costs increased


A decade of changes

• 1.1 million fewer soybean acres in Iowa1

• Increased seed prices2

–Up 108% from 2001

• Higher market values1

–$4.54/bu in 2000, $9.97/bu in 2010

1USDA-NASS; 2Neuman New York Times 2010


Increased insecticide use

• 130-fold increase in soybean since 20001

• ~73% soybean with seed treatment in 2009*

1Ragsdale et al. Ann Rev. Entomol. 2011; *Hodgson et al. Journal of Extension, in press


Percent increase of soybean acres treated with a foliar insecticide in 2009 compared to 2000 (1,423% average statewide increase).*


What are their soybean pests?*

Pest % Primary Pest % EncounteredSoybean aphid 93.8 97.6Bean leaf beetle 5.0 63.0Stink bugs 0.0 7.2Japanese beetle 0.6 17.9Potato leafhopper 0.2 7.0Thrips 0.0 0.9Spider mites 0.3 28.9Caterpillars 0.0 2.9Other 0.2 2.3


Are they scouting?

• IA growers reported fields are scouted weekly (60%) or every 2 weeks (34%)*

• Fields are scouted by themselves (55%), agribusiness (44%), and/or consultants (32%)*

• 17% use Speed Scouting regularly*


Newest management tool

• Host plant resistance– Naturally occurring germplasm– Commercially released in 2010– Single gene expression, Rag1– Moderate “killing power”

• Complementary to chemical control• Not widely promoted by industry yet


Awareness of HPR for SBA

• ~20% IA growers haven’t heard of HPR for SBA*

• ~43% IA growers said they would consider trying HPR*

Rag1 plot (left) and susceptible plot, heavily infested with soybean aphid. Note sooty

mold on the susceptible plants.


Where are they getting info?*Source % Used % Mostly/Very HelpfulAgribusiness 90.5 89.0Friends, Family 79.9 59.4ICM News 63.2 74.7Field Days 63.1 55.7ISU Personnel 58.6 72.5Websites 57.8 63.8Crop Advantage Series 41.5 70.3Outside Iowa 27.6 33.6ICM Conference 27.2 58.1Other 5.5 91.3


Survey Summary

• Soybean production has changed– Decision making is more complicated

• SBA is the primary pest• Most are scouting!• Getting info from many sources– Agribusiness is highly trusted– Where is agribusiness getting data?


New Survey Goals

• Repeat survey in 3 years• New pests, market?• Improve HPR awareness, IPM


QUESTIONS ABOUT THE SURVEY?


2011 SOYBEAN APHID EFFICACY EVALUATION


Methods

• Susceptible: 05RM310021; Rag1: 07JR801843• RCBD, 4 reps/treatment– # trts/location was variable

• 6 rows wide, 50 feet long


2011 ISU Research Farm Locations


Methods

• Sampled control plots weekly until July• Sampled all plots in Aug/Sept• Whole plant counts (20 -> 3)


Cumulative aphid days = Area under the curve

Economic threshold

Economic injury level


Methods

• Target application at threshold or R5

• Backpack sprayer– 20 gal H20, 40 psi


New for 2011…a 6-row sprayer!


Johnson Farm Northeast Farm

Northwest Farm• Variable pressure• Late peak >R6• Comparison of

Rag1 and susceptible


Johnson CAD and Yield ResultsPeak aphids = 110/plant; no yield differences

Rag1 suppressed

aphids


Northeast CAD and Yield Results

Rag1 suppressed aphids; yield was also lower…

Peak aphids = 425/plant

***

*


What is Transform?

• Dow AgroSciences• Sulfoxaflor; sulfoximine class (novel)• Activation of nicotinic acetylcholine receptors• Broad spectrum activity• Targeting fluid feeders • Should be approved for 2012


Northwest CAD and Yield ResultsPeak aphids = >800/plant

Rag1 suppressed aphids; yield was also higher…


Research Summary

• Variable aphid #’s between locations– Johnson, Northeast, Northwest

• Fields colonized mid-July, early August

• Applications made R5 (mid-August)


Research Summary

• Rag1 suppressed aphid growth at all locations

• Seed treatment further reduced CAD

• Foliar application at ET still protected yield

Northwest Farm


Summary

• HPR to soybean aphid is a new tool– Single gene with moderate resistance– Slowed population growth–Continue to scout–May exceed thresholds– Still need to protect yield


Summary

• Rag1 plots have fewer aphids• Can prevent ET and insecticides• Rag1 doesn’t cause yield drag– May not be in highest-yielding seed?

• Strongly encourage using Rag1 or Rag1+2


Acknowledgments

• ISU Farm Managers: Kent Berns, Ken Pecinovsky, Ryan Rusk

• Matt O’Neal, Mike McCarville• Mari Kemis, Brandi Geisinger


Where to get more information

• ICM News www.extension.iastate.edu/CropNews

• Soybean Aphid www.ent.iastate.edu/soybeanaphid/

• To see more talkswww.ent.iastate.edu/dept/faculty/hodgson

Free pubs and podcasts!


Please take a copy!

*Speaker evaluations would be appreciated! See me for details.


THANK YOU!

@erinwhodgson

Or visit my ISU Faculty webpage to see publications and

presentations!

soybean aphid efficacy program update 2011 icm conference, ames iowa update on the soybean aphid...

Documents

iowa soybean growers

soybean aphid93

ames iowa update

icm conference

fewer soybean acres

ames iowa background

ames iowa awareness

ames iowa survey goals