Black Cutworm Damage Reported in Northern Illinois

In a recent Bulletin article, I shared an observation of black cutworm damage in southern Illinois. Just recently (May 20), James Kennedy, Advanced Crop Care, Inc., found black cutworms were at work in northern Illinois as well. He found three fields that were infested with cutworms (4th instar) with cutting of plants in the 1-3% range. The fields were located in northern Kane County and McHenry County. James indicated that rescue treatments would be applied in the near future to these infested fields. The take home message — cornfields throughout Illinois (top to bottom) are potentially susceptible to black cutworm damage. As we near the Memorial Holiday weekend, it would be worthwhile to devote some effort to scouting fields for signs of leaf feeding and cutting.

I offer my thanks to James Kennedy for sharing his observations.

Mike Gray, Professor and Extension Entomologist

 


Plant Clinic Screening Waterhemp for Herbicide Resistance this Season

New testing for 2015: U of I Plant Clinic is offering molecular screening of waterhemp populations for resistance to glyphosate and PPO inhibitor herbicides this growing season. Protocols developed by University of Illinois Weed Scientist Dr. Pat Tranel, supported by Illinois Soybean Association and Pioneer, are now being offered through the Plant Clinic. The fee for the molecular testing is $50 per tested field. This includes both tests.
Herbicide-resistant waterhemp populations continue to expand into more areas of Illinois each season. Waterhemp has evolved resistance to herbicides encompassing more mechanisms of action than any other Illinois weed species. Not every individual waterhemp plant is resistant to one or more herbicides, but the majority of field-level waterhemp populations contain one or more types of herbicide resistance. Perhaps even more unnerving is the occurrence of multiple herbicide resistances within individual plants and/or fields. Don’t know if you have resistance or an application failure? Let us test it to get an answer for you.
To submit waterhemp weed samples:
After applying herbicide, select five waterhemp survivors in the field. Remove the top two inches from each plant (containing young, newly emerged, healthy leaves), and seal it in a sandwich-sized zip-top plastic bag. Use a separate bag for each plant. Do not place damp paper towels in bags. Place the bags in an envelope and send by overnight delivery to University of Illinois Plant Clinic. Ideally, samples should be sent the same day they are collected, but if necessary, they can be stored for a day or two in a refrigerator (but do not freeze). Do not send samples on a Friday or Saturday.
Submit the sample with the sample form; download form at this Plant Clinic website link:

http://web.extension.illinois.edu/plantclinic/downloads/WaterhempForm.pdf
Completely fill out the form for each field (1 field=5 plants=1 sample).
Additional Information: Please include herbicide use history, herbicides and rates applied this season, comments on observed weed control, and any other relevant information.

Need some Pigweed/Amaranth/Waterhemp ID practice? : See this recent article from Dr. Aaron Hager http://bulletin.ipm.illinois.edu/?p=3168

Waterhemp plant.

Waterhemp. University of Illinois Plant Clinic photo.

FAQ’s:
Question 1: I have Marestail, giant ragweed, etc. that I think is resistant to glyphosate. Will the Plant Clinic test it?
Answer 1: No, at this time our testing protocols are specific for Waterhemp.

Question 2: Do you test for all mechanisms for resistance to glyphosate and PPO inhibitors?
Answer 2: No, the protocol used for testing resistance to glyphosate looks for the amplification of the EPSPS gene. Dr. Tranel’s research indicates that this mechanism represents about 80% of glyphosate resistant waterhemp populations in Illinois. The PPO resistance protocol tests for a specific mutation in the PPX gene.
Question 3: Does ‘sensitive’ mean it’s not resistant to the herbicide(s)?
Answer 3: No, a test result of “sensitive” to glyphosate does not rule out the possibility that the plant actually is resistant, but by a resistance mechanism that is different than for what we are testing.

Suzanne Bissonnette


Cutworm Activity Reported in Southern Illinois: Scouting Fields Closely Recommended

John Pike, University of Illinois Crop Sciences Research Agronomist, Dixon Springs Agricultural Center, observed some cutting of corn plants today (May 18) in some plots that had volunteer ryegrass prior to burndown (Figure 1). John indicated that overall moth flight has been low at this location; however, as his observations illustrate, it is still worthwhile to scout fields closely for cutting activity. Please refer to some previously published Bulletin articles for additional information on this topic.

Figure 1. Black cutworm injury to corn, Dixon Spring Agricultural Center, May 18, 2015.

Figure 1. Black cutworm injury to corn, Dixon Springs Agricultural Center, May 18, 2015, Photograph taken by John Pike.

Please consider sharing other reports of black cutworm activity and I will pass along the information to readers of this Bulletin.

Mike Gray, Professor and Extension Entomologist


Projected Cutting Dates for Black Cutworms: Don’t Forget to Scout

Kelly Estes, Illinois Agricultural Pest Survey Coordinator, works with a network of volunteers across the state to monitor flights of key insect pests, including the black cutworm. Significant flights (nine or more moths trapped over 2-day period) of black cutworm moths occurred in Ford County (April 30), Mercer County (May 2), Lee County (May 4), Whiteside County (May 5), and Henry (May 10). By using these dates as a biofix and projecting heat unit accumulations we estimate that cutting of corn seedlings could begin to occur in fields on the following dates: Ford County (May 24), Mercer County (May 25), Lee County (May 31), Whiteside County (June 1), and Henry (June 3). Rather than wait until cutting begins to take place, producers are encouraged to look for early signs of leaf feeding as a potential indicator of cutting that may ensue. As stated in a previous Bulletin article, don’t assume that all Bt hybrids offer the same level of cutworm protection. Plants in the 1- to 4-leaf stage are most susceptible to cutting. Cutting of plants earlier than these projected cutting dates is possible — localized intense flights may have occurred and were not picked up by our volunteers. For more information on the biology, life cycle, and scouting procedures I encourage you to review our Department of Crop Sciences black cutworm fact sheet.

Mike Gray, Professor and Extension Entomologist


US EPA’s Proposal to Prevent Western Corn Rootworm Resistance: Does IPM Implementation Have a Realistic Chance?

On January 28, 2015, the United States Environmental Protection Agency (US EPA)  published a “proposed framework to prevent corn rootworm resistance.” Public comments were sought across an original 45-day period that was extended 30 days beyond the original March 16, 2015 deadline. Within the proposal, the United State EPA acknowledges that corn rootworms have already developed resistance to “Bt corn” in some areas of Iowa and Illinois. US EPA has characterized some states within the Corn Belt as in the “red zone” and these include Iowa, Illinois, Nebraska, western Indiana, southwestern Wisconsin, southern Minnesota, and eastern South Dakota. The so-called “red zone” states are described by the US EPA as follows: “where corn rootworm infestations are common and the use of Bt corn is high, …” The Agency’s proposal also adds that producers may be part of the “red zone” if the following circumstances are met: 1) “corn-on-corn for multiple years”, 2) “heavy use of Bt corn”, 3) “regular corn rootworm infestations”, and 4) “spotty compliance with current refuge requirements.” As part of the US EPA’s proposed framework they offer the following proposal: “In areas at risk for corn rootworm resistance, to require crop rotation, use of corn varieties containing more than one Bt protein, or other integrated pest management (IPM) strategies and stewardship for corn rootworm.” Additionally, the US EPA proposes the following: “70% of corn acres in the “red zone” should take part in IPM efforts and that 50% of corn acres in non-“red zone” areas should participate in IPM efforts.” From my perspective, isn’t this setting the bar a bit low? Why not propose that some form of IPM be put in place on 100% of corn acres regardless of zone characterization?

In reaction to this US EPA proposal, not surprisingly, numerous comments have been received and published including a letter that I signed along with 14 other entomologists from 12 prominent institutions. I encourage you to review these comments from many individuals and organizations. As you will see, there are many different perspectives and opinions taken on this controversial proposal. Among the many concerns raised by the proposal are those that involve the use of a planting-time soil insecticide with Bt hybrids. Let me be clear — planting-time soil insecticides should be considered an important arrow in the IPM quiver targeted at the corn rootworm complex.However, the addition of a planting-time soil insecticide along with a corn rootworm Bt hybrid is not a good resistance management strategy. The authors of two recently published journal articles have confirmed that use of a planting-time soil insecticide with a rootworm Bt hybrid delays emergence and increases the chances of non-random mating (promotes assortative mating); thereby, hastening the onset of resistance to Bt proteins. The citations for these journal articles are provided below:

Petzold-Maxwell, J.L. et al. 2013. Effect of Bt maize and soil insecticides on yield, injury, and rootworm survival: implications for resistance management. Journal of Economic Entomology 106(5): 1941-1951.

Frank, D.L. et al. 2015. Effect of seed blends and soil-insecticide on western and northern corn rootworm emergence from mCry3A + eCry3.1Ab Bt maize. Journal of Economic Entomology DOI: 10.1093/jee/tov081

Planting-time soil insecticides will remain an important tool targeted at the secondary insect complex when present at economically threatening levels. They also represent an important option when used with non-Bt hybrids in fields with corn rootworm infestations. When a planting-time soil insecticide is used with a pyramided Bt rootworm hybrid for the sole purpose of rootworm protection, it’s hard to find any convincing argument that this is a good IPM or resistance management (IRM) approach.

Resistance by many pests, including corn rootworms, has occurred when we have used the same arrow over and over again and failed to integrate management tactics. Since 2003, the year in which Bt rootworm hybrids were commercialized, growers have increasingly failed to integrate tactics and have relied upon a narrow set of Bt rootworm proteins expressed at low levels within a refuge system designed for high-dose events targeted at European corn borers. We should not have been surprised when reports of western corn rootworm resistance to Bt corn began to occur in Iowa soon followed by Illinois. Finally, while I am supportive of crop rotation as a viable pest management tactic for corn rootworms in many areas of the Corn Belt, growers in east central and northeastern counties of Illinois recognize that a segment of the western corn rootworm population in those areas is now resistant to two Bt proteins (Cry3Bb1 and mCry3A) as well as crop rotation. Rotation, even in those Illinois counties, remains a good strategy; however, other tactics will need to be more fully integrated into a long-term corn rootworm management program.

Mike Gray, Professor and Extension Entomologist


Black Cutworm Moth Captures Common in Several Midwestern States

Impressive flights of black cutworm and armyworm moths have been reported by Doug Johnson an Extension Entomologist at the University of Kentucky . Entomologists at Purdue University also have received reports that black cutworm moth captures are now common in many areas of Indiana. Kelly Estes, Agricultural Pest Survey Coordinator with the Illinois Natural History Survey, has established a network of trapping cooperators across Illinois. Although no intense flights (nine or more moths caught over a 2-day period) of black cutworm moths have been reported by these cooperators, captures of this species have been common the past two weeks in the following counties: Champaign, Fayette, Logan, Lee, Macon, Macoupin, and Madison. This distribution of captures suggests that black cutworm moth flights have likely taken place throughout Illinois and growers are encouraged to remain vigilant for early signs of leaf feeding when corn seedlings begin to emerge. Today (April 21) strong winds from the south are undoubtedly bringing many black cutworm moths into Illinois and fields like the one featured in the photograph below will be prime targets for egg laying by this species.

Champaign County field considered a prime target for black cutworm moth egg laying, April 21, 2015.

 

For more complete information about the biology, life cycle, and management of black cutworms and armyworms, fact sheets are available from the Department of Crop Sciences, UIUC. Provided below is a brief overview of some key life cycle and management facts concerning black cutworms.

  • Black cutworm moths are strong migratory insects with northward flights commonly observed from Gulf States into the Midwest from March through May.
  • Moths are attracted to fields heavily infested with weeds such as chickweed, shepherd’s purse, peppergrass, and yellow rocket.
  • Late tillage and planting tends to increase the susceptibility of fields to black cutworm infestations.
  • Cutting of corn plants begins when larvae reach the 4th instar — with a single cutworm cutting an average of 3 to 4 plants during its larval development.
  • Cutting tends to occur most often during nights or on dark overcast days.
  • Fields at greatest risk to cutting and economic damage are in the 1-to-4 leaf stage of plant development.
  • An early warning sign of potential economic damage includes small pinhole feeding injury in leaves (caused by the first 3 instars).
  • A nominal threshold of 3% cutting of plants has traditionally been used as a point at which growers should consider a rescue treatment.
  • Not all Bt hybrids offer adequate protection against black cutworm damage. Growers should consult the Handy Bt trait table prepared by Dr. Chris DiFonzo at Michigan State University to determine the level of protection provided by their chosen Bt hybrid.

As the season progresses, if you learn of significant black cutworm infestations, please let me know and I will share this information with the readers of this Bulletin.

Mike Gray, Extension Entomologist


Newly Published Report Confirms Extensive Use of Insecticidal Seed Treatments in Field Crops

On March 20, 2015, an article published in Environmental Science and Technology confirmed the extensive use of neonicotinoids as insecticidal seed treatments in a wide variety of field crops across the United States. The authors of the article Margaret R. Douglas and John F. Tooker are scientists with the Department of Entomology at The Pennsylvania State University.

Provided below are some direct quotes from their journal article concerning neonicotinoid seed treatments (NSTs):

  • “Neonicotinoid use increased rapidly between 2003 and 2011, as seed-applied products were introduced in field crops, marking an unprecedented shift toward large-scale, preemptive insecticide use: 34-44% of soybeans and 79-100% of maize hectares were treated in 2011. This finding contradicts recent analyses, which concluded that insecticides are used today on fewer maize hectares that a decade or two ago.”
  • “Importantly, the introduction of NSTs closely followed introduction of Bt hybrids targeting corn rootworms (Diabrotica spp.), a pest complex that has historically driven insecticide use in U.S. maize.”
  • “Importantly, however, NSTs are now used on almost triple the area historically treated with non-seed insecticides; therefore, NSTs (together with Bt hybrids) have more than displaced non-seed treatment insecticide use on an area basis.”
  • “This finding supports the apparent shift toward an “insurance” paradigm of pest management in maize, in which transgenic crops and NSTs are deployed even when target pest densities are expected to be low. This notion is also supported by a recent survey, in which 39% of maize growers using NSTs were not targeting any particular pest.”
  • “Several analyses on the influence of Bt crops on pesticide-use patterns do not seem to have considered seed treatments, and so may have overstated reductions in insecticide use (especially “area treated”) associated with this technology.”

The widespread insurance-based approach to the use of NSTs is likely to persist in corn and escalate in soybean production due to (as the authors of the current journal article point out) — “current incentives and disincentives for farmers and seed suppliers.” As a result, concerns will linger regarding secondary-insect resistance development and potential negative environmental consequences.

Mike Gray


2015 Handy Bt Trait Table Now Available

In the transgenic era, the most important insect management decision a corn producer makes is deciding which type of corn hybrid to plant — a Bt hybrid or a non-Bt hybrid? This decision is typically made in the fall or early winter, well before planting ensues. In a sense, a producer who elects to plant a Bt hybrid takes out an insurance plan against a wide range of insect pests for the upcoming growing season. I have referred to this in previous Bulletin articles as — insurance pest management, the new and most popular form of IPM across the Corn Belt. According to the USDA Economic Research Service, 80% of corn grown in the United States during 2014 was a Bt hybrid.

Once again, we have Professor Chris DiFonzo, Department of Entomology, Michigan State University, to thank for preparing an updated Handy Bt Trait Table. Within this table Professor DiFonzo provides information on trade and event names, specific Cry proteins expressed, refuge requirements, herbicide tolerance characteristics, and targeted insect species. Producers are encouraged to pay particular attention to whether or not a specific Bt hybrid offers control or suppression of a given insect pest. Many of the Bt hybrids now offer a wide range of insect protection above ground (e.g. European corn borer, black cutworm, fall armyworm, corn earworm, stalk borer, western bean cutworm) and below ground (corn rootworm). In addition, producers need to ensure that they are deploying the proper refuge with their Bt hybrid of choice. Although seed blend refuges (5% and 10%) are becoming more common, use of some Bt hybrids requires a structured refuge. The level of complexity regarding refuge requirements for the wide variety of Bt hybrids has increased in recent years.

Recently, bioassays conducted by Dr. Joe Spencer, an entomologist with the Illinois Natural History Survey, have confirmed western corn rootworm resistance to the Cry3Bb1 protein in several Illinois counties (Henry, Kankakee, Livingston, McDonough, Mercer, Sangamon, and Whiteside). A segment of the western corn rootworm population has developed cross resistance to the mCry3A protein and resistance to crop rotation in Kankakee and Livingston counties. Producers who have not been satisfied with the level of root protection afforded by a Bt hybrid and suspect resistance, should consider planting a pyramided Bt rootworm hybrid — a hybrid that expresses more than one Cry protein targeted at corn rootworms. Crop rotation also should be considered by producers in fields with a history of continuous corn production. For producers who elect not to rotate crops, nor use a pyramided Bt rootworm hybrid, the planting of a non-Bt hybrid along with a planting-time soil insecticide is an option. The key to successful long term management of corn rootworms is utilization of an integrated approach — alternating tactics and thus hopefully avoiding resistance development. Unfortunately, the history of western corn rootworms is one of repeating past mistakes and development of resistance to nearly every management strategy.

A final note — black cutworm moths are migrating into the state of Illinois and growers who elect not to plant a Bt hybrid offering control against this pest should remain especially vigilant for early signs of leaf feeding once corn seedlings begin to emerge. Fields at most risk include those heavily infested with winter annual weeds.

Mike Gray, Professor & Extension Entomologist, Department of Crop Sciences, University of Illinois


Spring Cover Crop Field Day March 26th – Ewing Demonstration Center

Join us on Thursday, March 26th, 2015 for the  Spring Cover Crop Field Day at the University of Illinois Extension Ewing Demonstration Center.  Registration will start at 8:30 a.m. and the program will begin at 9:00 a.m., rain or shine.  The Ewing Demonstration Center is located at 16132 N. Ewing Rd; Ewing, IL 62836, on the north edge of the village of Ewing, north of the Ewing Grade School on north Ewing Road.  Watch for signs.

Cover crops have many benefits to the soil, environment, and overall crop production and management.  Topics covered during this field day program include:

Challenges of Grazing Lush Spring Forage

–          Travis Meteer, Extension Educator, U of I Extension

Techniques for Planting into Cover Crop Residue

–          Mike Plumer, Private Consultant

Understanding the Soil Profile Beneath Your Feet

–          Bryan Fitch, Resource Soil Scientist, NRCS

Which One to Choose? Cover Crop Species Selection and Demonstration Trial Tour

–          Nathan Johanning, Extension Educator, U of I Extension

Some of the program highlights will be the demonstration trial planting of cover crops, including 17 different cover crops and combinations illustrating first hand the characteristics of the cover crops and what benefits they bring to your soil and crop production system.  Also, (weather and soil conditions permitting) we will have a soil pit dug, exposing the soil profile, where NRCS Resource Soil Scientist, Bryan Fitch will lead us through the characteristics of our southern Illinois soils to enhance understanding of the importance of a healthy soil.  Also Certified Crop Advisor CEU credits will be available (2.0 Soil & Water Management & 1.0 Crop Management) for the program.

This field day will be free and open to anyone interested in learning more about cover crops.  A light lunch will be provided and this is a great way to talk to fellow growers to learn more from their challenges and successes incorporating cover crops into their cropping systems.  Please call the Franklin County Extension Office at 618-439-3178 for more information and to register by March 24th.  We hope to see you there!


Note Correct Dates: 2015 Regional Crop Management Conferences

Registration is now open for the 2015 regional Crop Management Conferences. These 2-day conferences in January and February provide a forum for discussion and interaction among participants and university researchers and are designed to address a wide array of topics pertinent to crop production in Illinois.

Certified Crop Advisers can earn up to 13 hours of continuing education credit. Advance registration, no later than one week before each conference, is $130 per person. Late and on-site registration is $150. Dates and locations along with links to location-specific agendas and online registration are listed below.

Conference topics vary by location but may include:

  • Management of Sudden Death Syndrome in Soybean
  • Cover Crops in Illinois Row Crop Production: Answers or More Questions?
  • Corn and Soybean Agronomy: Will What Worked in 2014 Work in 2015?
  • Managing Inputs and Field Crops Insects in 2015
  • Biology and Management of Wheat Insects
  • Soil Health
  • Impact of Ohio, Mississippi, and Illinois River Flooding on Private and Public Illinois Lands
  • Is Varietal Maturity a Big Factor in Soybean Yield Determination?
  • The Illinois Nutrient Loss Reduction Strategy: What’s in it for Agriculture?
  • Update on Plant-Parasitic Nematodes in the Midwest
  • A Behind-the-Scenes Look at Confirming Herbicide Resistance
  • Agronomy Data: Filter the Kool-Aid Before You Drink It
  • Climate Variability in Illinois and How to Plan for It
  • Plant Clinic Chronicle: Rotten Stems and Other Maladies
  • 40 Years of Tillage x Fertility Research: What Have We Learned?
  • New (and Old) Tools for Delaying and Coping with Herbicide Resistance

January 21-22: Mt. Vernon – Krieger/Holiday Inn Convention Center. Click here to view the topics to be featured in Mt. Vernon. Click here to register for the Mt. Vernon location. For more information, contact Robert Bellm: (618) 427-3349, rcbellm@illinois.edu.

January 28-29: Springfield – Northfield Inn Conference Center. Click here to view the topics to be featured in Springfield. Click here to register for the Springfield location. For more information, contact Robert Bellm: (618) 427-3349, rcbellm@illinois.edu.

February 4-5:  Champaign – i-Hotel and Conference Center. Click here to view the topics to be featured in Champaign. Click here to register for the Champaign location. For more information, contact Dennis Bowman: (217) 244-0851, ndbowman@illinois.edu.

February 11-12: Malta – Kishwaukee College Conference Center. Click here to view the topics to be featured in Malta. Click here to register for the Malta location. For more information, contact Russ Higgins: (815) 274-1343), rahiggin@illinois.edu