North Carolina Corn Insect Pest 2014 Update Dominic Reisig NCSU Entomology

Contents of This Presentation Refuge compliance Does corn earworm impact corn yield? Cry1F-resistant fall armyworm Seed treatment value for NC corn Resistance development of corn earworm to Bt Stink bug management in corn Research Issues Not in This Presentation

DescriptionCaterpillar TraitsRootworm Traits Agrisure CB/LLCry 1AB (Bt11)None Agrisure 3000GTCry 1AB (Bt11)Cry 3A (modified) Herculex I (HX1)Cry 1F (HX1)None Herculex XTRA (HXX)Cry 1F (HX1)Cry 34/35Ab1 YieldGard VT Triple (VT3)Cry 1AB (YGCB)Cry 3Bb1 Genuity VT Triple Pro (GENVT3P)Cry 1A Cry2Ab2Cry 3Bb1 Genuity VT Double Pro (GENVT2P)Cry 1A Cry2Ab2None Genuity VT Double Pro RIB (GENVT2P RIB)Same as above + RIB *None Genuity or Dow AgroSciences SmartStax (GENSS or SSX) Cry 1A Cry2Ab2 + Cry 1F (HX1) Cry 3Bb1 + Cry 34/35Ab1 Genuity or Dow AgroSciences SmartStax RIB (GENSS or SSX) Same as above + RIB * Agrisure Viptera 3110Cry 1Ab (Bt11) + VIP3A (MIR162)None Agrisure Viptera 3111Cry 1Ab (Bt11) + VIP3A (MIR162)Cry 3A (modified) Agrisure Viptera 3220 Cry 1Ab (Bt11) + VIP3A (MIR162) + Cry1F (HX1) None Optimum IntrasectCry1Ab (YGCB) + Cry 1F (HX1)None Optimum AcreMaxCry1Ab (YGCB) + Cry 1F (HX1)None Optimum AcreMax XtraCry1Ab (YGCB) + Cry 1F (HX1)Cry 34/35Ab1 Traits of Selected, Commercially Available Bt Corn Products * Non-Bt Refuge in Bag Slide adapted from Scott Stewart, U. Tennessee

* Unless Cry1F-resistant fall armyworm is present Slide adapted from Scott Stewart, U. Tennessee Traits / BrandsCorn borersCutworm Corn earworm Fall armyworm Western corn rootworm Agrisure CB/LLExcellentPoorFairGoodNone Agrisure 3000GTExcellentPoorFairGood Herculex I (HX1)ExcellentGoodPoorVery Good *None Herculex XTRA (HXX)ExcellentGoodPoorVery Good *Excellent YieldGard VT Triple (VT3)ExcellentPoorFair Excellent Genuity VT Triple Pro (GENVT3P)ExcellentPoorGoodVery GoodExcellent Genuity VT Double Pro (GENVT2P)ExcellentPoorGoodVery GoodNone Genuity VT Double Pro RIB (GENVT2P RIB)ExcellentPoorGoodVery GoodNone Genuity or Dow AgroSciences SmartStax (GENSS or SSX)ExcellentGood Very Good Very Good *Excellent Genuity or Dow AgroSciences SmartStax RIB (GENSS or SSX)ExcellentGood Very Good Very Good *Excellent Agrisure Viptera 3110ExcellentGoodExcellent None Agrisure Viptera 3111ExcellentGoodExcellent Good Agrisure Viptera 3220Excellent Very Good Excellent None Optimum IntrasectExcellent Very Good FairVery Good *None Optimum AcreMaxExcellent Very Good FairVery Good *None Optimum AcreMax XtraExcellent Very Good FairVery Good *Excellent Relative Efficacy of Selected, Commercially Available Bt Corn Products

Traits / BrandsRefuge Requirement Agrisure CB/LL50%In-field, adjacent, block ½ mile Agrisure 3000GT50%In-field, adjacent, block ½ mile Herculex I (HX1)50%In-field, adjacent, block ½ mile Herculex XTRA (HXX)50%In-field, adjacent YieldGard VT Triple (VT3)50%In-field, adjacent Genuity VT Triple Pro (GENVT3P)20%In-field, adjacent Genuity VT Triple Pro RIB (GENVT3P RIB)20% + RIB *In-field, adjacent Genuity VT Double Pro (GENVT2P)20%In-field, adjacent, block ½ mile Genuity VT Double Pro RIB (GENVT2P RIB)20% + RIB *In-field, adjacent Genuity or Dow AgroSciences SmartStax (GENSS or SSX)20%In-field, adjacent, block ½ mile Genuity or Dow AgroSciences SmartStax RIB (GENSS or SSX)20% + RIB *In-field, adjacent, block ½ mile Agrisure Viptera %In-field, adjacent, block ½ mile Agrisure Viptera %In-field, adjacent Agrisure Viptera %In-field, adjacent, block ½ mile Optimum Intrasect20%In-field, adjacent, block ½ mile Optimum AcreMax20% + RIB *In-field, adjacent, block ½ mile Optimum AcreMax Xtra20% + RIB *In-field, adjacent, block ½ mile Refuge Requirements (Southern US) of Selected, Commercially Available Bt Corn Products * Non-Bt Refuge in Bag Slide adapted from Scott Stewart, U. Tennessee

Why refuge? Slide adapted from Department of Soil and Crop Sciences at Colorado State University

Example Refuge Configurations Image adapted from Canadian Corn Pest Coalition

Common Refuge Questions Can the refuge be protected from lep. pests? – Yes, using non-Bt insecticides How should the refuge hybrid be selected? – Chose a hybrid with a similar maturity and plant it as close in time as possible to the Bt hybrid What happens to those who don’t plant refuge? – Required by law through EPA – Contract occurs at time of purchase of Bt hybrid – Warning letter on first offense, with compliance assessment the following year – No Bt corn after second offense (in consecutive year)

Common Refuge Questions Who checks for compliance – Independent third parties Telephone survey, on-farm visits Are seed purchases tracked? – Of course, but companies don’t share information How can I know the refuge requirement? – Check the bag tag – Online search “refuge calculator” Yes, there is an app for that- iPhone and Android…

Common mid- to late-season lep. pest Occasional mid- to late-season lep. pests Cutworm Armyworms Southern cornstalk borer European corn borer Corn earworm

No control Agrisure RW Herculex RW YieldGard Rootworm YieldGard VT Rootworm/RR2 Poor-fair control Herculex I Herculex XTRA Fair-good Very good YieldGard VT2 Pro YieldGard VT Triple Pro SmartStax Agrisure CB/LL YieldGard Corn Borer Agrisure CB/LL/RW Agrisure GT3000 YieldGard Plus YieldGard VT Triple Corn earworm control with Bt hybrids Excellent Agrisure Viptera Slide from F.P.F. Reay-Jones, Clemson U.

To date, I have not documented a single yield loss due to corn earworm feeding in the ear in North Carolina Does corn earworm impact yield?

Example of past experiment- 2011

Does Corn Earworm Affect Yield? Plots of 14 rows x 50 ft planted in Florence, SC, and in Plymouth, NC (n = 4 replications). Near-isolines for Bt and non-Bt hybrids (HX1; HX1 + YGCB; VT3; VT2Pro). Applications of Prevathon (20 oz/ac) twice a week (15 applications in Florence, 18 applications in Plymouth) using a backpack sprayer. Created treated and untreated subplots Sampled 20 ears per plot for corn earworm injury and yield

Florence, SCPlymouth, NC Area of Kernels Injured by Earworm in 2012 = hybrids shared same genetic background

Florence, SCPlymouth, NC Area of Kernels Injured by Earworm in 2013 = hybrids shared same genetic background

Relationship between feeding and yield

Conclusions Corn earworm did not affect yield (NC or SC) Hybrids should be chosen based on other agronomic considerations than earworm Bt is probably still necessary for stalk pests (southern cornstalk borer & European corn borer) Some of these genes active against corn earworm also have activity on other pests – May have fit for late-planted corn – Aflatoxin level may be reduced by eliminating earworm, but effect is highly dependent on hybrid genetics and environment armyworm

Safe for any use Fit only for cattle, will not accept above this level Non-Bt

Cry1F-resistant fall armyworm found in Hyde County, 2013

What adjustments should we make in 2014? Hybrids with Genuity SmartStax, Herculex and Optimum Intrasect contain Cry1F – Widestrike countains Cry1F + Cry1Ac Closely monitor corn and cotton for resistance – August Plant refuge