Overpower Corn Rootworm
To defeat corn rootworm, you not only need to incorporate the latest trait technology, but also best management practices. Get a collection of corn rootworm (CRW) tips, management resources and find answers to your top questions on how to best manage your CRW acres here.
Your Top CRW Questions Answered
What is RNAi exactly? How does it protect against corn rootworm? And how is it different than the CRW traits I’m planting now? This video breaks down the RNAi process to answer every question you may have to best protect your acres from those troublesome insects.
Why is corn rootworm such a perennial problem?
Of all the pests that threaten corn yields, none have the seemingly infinite capability to adapt and overcome management strategies that corn rootworm (CRW) has displayed. These adaptations are how CRW continues to cause over a billion dollars in damage yearly across the US.
1. CRW has adapted to overcome crop rotation
Rootworms’ ability to evolve has made crop rotation ineffective in many areas. The soybean variant western corn rootworm has evolved to lay eggs in non-corn fields. The northern corn rootworm has shown extended diapause, in which eggs remain viable in the soil for several years before hatching.
2. Damaged roots are a gateway to other yield threats
Plants with damaged root systems are more susceptible to drought stress and lodging, meaning rootworm damage is a gateway to a host of additional yield threats.
3. CRW damages corn during its whole lifecycle
Rootworm larvae AND adults cause severe problems, which means potential issues all season long. Adult CRW feeding on corn silks during pollination can cause poor seed set and subsequent yield loss.
4. CRW have evolved with technology
Resistant corn rootworm populations have now been documented for all four commercially available Bt proteins for CRW control.
Q: Why should I scout for CRW if traits are protecting the corn?
A: No solution is foolproof. Larvae scouting will help in-season to determine a response if needed.
CRW will surprise you. Root digs and sticky traps can determine rootworm pressure (when done right) and help you make the best decision. Sticky traps can be used to estimate adult CRW populations, a crucial warning for next year’s populations.
Don’t assume pressure is uniform
CRW pressure varies field-to-field and can significantly vary within a field.
Use root digs early to spot larvae
Scouting should begin in early to mid-June or when corn is between V6 to V12. Dig up 2 plants at each of 5 locations within the soil from 6” to 8" around the plant and sift soil over a sheet of black plastic, looking for 1/32” to ½” long larvae.
We dig so you don’t have to
Corteva research digs tens of thousands of roots every year in the most challenging CRW environments we can find to test how the industry’s traits are holding up.
Beetles in sticky traps have already laid the next season’s yield robbers
Sticky traps are good for field-to-field observations and will help you make a better-informed decision on next seasons management options. But don’t use sticky traps for hybrid-to-hybrid population comparisons as CRW can move up to a ½ mile radius and come from another location.
Q: Is there really no "plant it and forget it" solution for CRW management?
A: While limited CRW trait technologies exist and new RNAi technology is exciting, it’s not a standalone solution to the full CRW problem.
Only limited CRW trait technologies exist and many seed brands use the same ones. This makes it important to know what traits and genetics you’re planting and to always follow CRW best management practices.
Different hybrids might have the same Bt trait
Many seed brands use the same CRW traits. Simply switching brands does not necessarily mean switching to different CRW traits. The chart below breaks down different brands and what traits they use to defend against CRW.
ABOVE- AND BELOW-GROUND INSECT PROTECTION
| Above-ground insect protection event (protein) | Below-ground insect protection event (protein/gene) | Herbicide tolerance (HT) (event/gene) | Refuge requirement - Corn belt unless otherwise designated | ||
|---|---|---|---|---|---|
| Options in the Pioneer® brand portfolio | Qrome® PRODUCTS | DP4114 (Cry1F), MON810 (Cry1Ab) | DP4114 (Cry34/35Ab1), MIR604 (mCry3A) | glyphosate (NK603), glufosinate (pat) | INTEGRATED 5% glyphosate, glufosinate HT |
| Optimum® AcreMax® XTreme PRODUCTS | TC1507 (Cry1F), MON810 (Cry1Ab) | DAS59122 (Cry34/35Ab1), MIR604 (mCry3A) | glyphosate (NK603), glufosinate (pat) | INTEGRATED 5% glyphosate, glufosinate HT | |
| Vorceed™ Enlist® corn PRODUCTS | DP4114 (Cry1F), MON89034 (Cry1A.105 + Cry2Ab) | DP4114 (Cry34/35Ab1), MON87411 (DvSnf7 + Cry3Bb1) | 2,4-D choline + FOP (DAS40278), glyphosate (MON87411), glufosinate (pat) | INTEGRATED 5% 2,4-D choline, glyphosate, glufosinate, FOP HT | |
| Competitive products | SmartStax® Technology | TC1507 (Cry1F), MON89034 (Cry1A.105 + Cry2Ab) | MON88017 (Cry3Bb1), DAS59122 (Cry34/35Ab1) | glyphosate (MON88017), glufosinate (pat) | INTEGRATED 5% glyphosate, glufosinate HT |
| SmartStax® PRO Technology | TC1507 (Cry1F), MON89034 (Cry1A.105 + Cry2Ab) | MON87411 (DvSnf7 + Cry3Bb1), DAS59122 (Cry34/35Ab1) | glyphosate (MON87411), glufosinate (pat) | INTEGRATED 5% glyphosate, glufosinate HT | |
| VT4PRO™ with RNAi Technology | MON89034 (Cry1A.105 + Cry2Ab2) and MIR162 (Vip3Aa20) | MON87411 (DvSnf7 + Cry3Bb1) | glyphosate (MON88017) | INTEGRATED 5% glyphosate, glufosinate HT | |
| Agrisure® Duracade® 5122 E-Z Refuge® corn | TC1507 (Cry1F), Bt11 (Cry1Ab) | MIR604 (mCry3A), 5307 (eCry3.1Ab) | glyphosate (GA21), glufosinate (pat) | INTEGRATED 5% glyphosate HT | |
Genetics still matter
The bigger difference from seed brands comes from the genetics of the hybrids, like yield potential, root strength or disease tolerance.
RNAi takes time to kill CRW
The RNAi trait can take up to 12 days to kill CRW, a window in which large amounts of feeding damage can still occur. Stacking RNAi technology with other CRW traits that act immediately, including Bt traits with the Cry34/35 protein, helps eliminate this gap. See more on CRW traits in the chart below and which insects different brands defend against.
ABOVE- AND BELOW-GROUND INSECT PROTECTION
| Corn rootworm (western#, northern, Mexican) | European corn borer | Southwestern corn borer# | Black cutworm | Corn earworm# | Western bean cutworm# | Fall armyworm# | Herbicide tolerance | ||
|---|---|---|---|---|---|---|---|---|---|
| Options in the Pioneer® brand portfolio | Qrome® PRODUCTS | ++▼ | +++▼ | +++▼ | ++ | + | - | ++ | glyphosate, glufosinate |
| Optimum® AcreMax® XTreme PRODUCTS | ++▼ | +++▼ | +++▼ | ++ | + | - | ++ | glyphosate, glufosinate | |
| Vorceed™ Enlist® corn PRODUCTS | +++▼ | +++▼ | +++▼ | ++ | + | - | ++▼ | 2,4-D choline, glyphosate, glufosinate, FOP | |
| Competitive products | SmartStax® Technology | ++▼ | +++▼ | +++▼ | ++ | + | - | ++▼ | glyphosate, glufosinate |
| SmartStax® PRO Technology | +++▼ | +++▼ | +++▼ | ++ | + | - | ++▼ | glyphosate, glufosinate | |
| VT4PRO™ with RNAi Technology | ++▼ | +++▼ | +++▼ | +++ | +++ | +++ | +++▼ | glyphosate | |
| Agrisure® Duracade® 5122 E-Z Refuge® corn | ++▼ | +++▼ | +++▼ | ++ | + | - | ++ | glyphosate, glufosinate | |
+++ Excellent protection | ++ Good Protection | + Some protection | - No activity/not labelled | ▼ 2 or more working modes of action.
CRW best management practices should still be followed
An integrated approach to CRW management will always be the most successful. These include industry best practices like crop rotation, suppressing larval development, insecticides and more. See below for CRW Best Management Practices.
Break the Cycle
Removing the CRW traits from the field every 3rd year will preserve both the Bt and RNAi traits.
- Rotate to soybeans or another non-host crop.
- Avoid three or more years of continuous CRW trait use.
- If low CRW populations are anticipated, consider planting a non-CRW traited product along with a soil-applied insecticide or the Enhanced CRW Package of LumiGEN® seed treatments for additional protection.
Manage Populations
Know your CRW populations so you can reduce the risk of significant root injury the following season.
- Utilize sticky traps to scout your fields for weekly presence of adult CRW beetles from silking through grain fill.
- Use action thresholds to determine whether to apply a foliar insecticide to reduce CRW populations.
- The RNAi technology in Vorceed® Enlist® Corn provides another effective tool for managing CRW populations in fields.
- Check for root injury to determine the effectiveness of your current management plan.
Protect Yield Potential
If high CRW populations are anticipated for the upcoming season, utilize multiple modes of action for control.
- Plant a product with multiple modes of action of control against CRW, such as Pioneer® brand Vorceed® Enlist® or Qrome® products with the Enhanced CRW Package insecticide seed treatment for additional protection.
- Application of a soil-applied insecticide in addition to using a CRW traited product is not recommended for control of CRW except in limited circumstances. Consult with your Pioneer agronomist, extension service, crop consultant, or other local experts for further guidance.
Q: Do I have to give up key agronomic traits or yield potential to get the CRW traits I need?
A: No! There’s no need to sacrifice hybrid performance for CRW protection, you can have both.
With limited traits to combat CRW, it’s important not to lose sight of the advantages from powerful agronomic traits and excellent yield potential. CRW traits are important for root health on high-pressure CRW acres, but they’re not the full story. High yield potential and strong agronomic traits like native root strength and disease tolerance play critical roles in overall plant health. Check out the advantages of the next generation of CRW control with Pioneer® brand Vorceed® Enlist® corn.
12.1 bu/A yield advantage
In 2023, Vorceed Enlist corn products edged out competitive hybrids by an average of 12.1 bu/A vs. competitor SmartStax and SmartStax PRO products. 71% wins across 4,676 comparisons.¹
A new mode of action for CRW protection
Vorceed Enlist corn features three ways to protect against CRW – including an RNAi approach. See the different traits below.
Bred for agronomics and protection
Pioneer brand Vorceed Enlist corn represents a whole corn solution with superior yield protection, agronomics and weed control – leading to more product options and flexibility for your acres. CRW and tough weeds won’t know what hit them.
Experience More Yield, Protection and Flexibility
Plant Pioneer® brand Vorceed® Enlist® corn for a whole-farm solution to help maximize ROI potential on your CRW acres. Find the right hybrid for your operation.
Control CRW: Vorceed Enlist
#Various factors, including pest pressure, reduced susceptibility, and insect resistance in some pest populations may affect efficacy of certain corn technology products in some regions. To help extend durability of these technologies, Corteva Agriscience recommends you implement Integrated Pest Management (IPM) practices such as crop rotation, cultural and biological control tactics (including rotating sources of Bt-protected corn traits), pest scouting, and appropriate use of pest thresholds when employing management practices such as insecticide application. You must also plant the required refuge when using these technologies. Please contact your sales professional or consult with your local university extension for more information regarding insect resistance management guidelines, best management practices and to understand whether there has been a shift in susceptibility or insect resistance with certain pests documented in your area. *Western bean cutworm has been removed from the Corteva Agriscience product use statement for several corn products that contain Herculex® I (Cry1F) but lack another mode of action for western bean cutworm due to a wide-spread decrease in susceptibility indicating the possibility of field-evolved resistance to Cry1F in most geographies.
1Data is based on an average of 2023 comparisons made in the U.S. through April 23, 2024. Comparisons are against all comparisons, unless otherwise stated, and within +/- 3 CRM of the competitive brand. Product responses are variable and subject to a number of environmental, disease and pest pressures. Individual results may vary. Multi-year and multi-location data are a better predictor of performance. DO NOT USE THIS OR ANY OTHER DATA FROM A LIMITED NUMBER OF TRIALS AS A SIGNIFICANT FACTOR IN PRODUCT SELECTION. Contact your Pioneer sales representative or sales professional for the latest and complete listing of traits and scores for the products provided subject to the terms and conditions of purchase which are part of the labeling and purchase documents.