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


The Agenda for the 2015 University of Illinois Corn & Soybean Classics

With the 2014 harvest nearing completion, I would like to take this opportunity to announce the agenda for the 2015 University of Illinois Corn & Soybean Classics.  We look forward to welcoming back many who have attended one or more of our previous meetings and extend a warm welcome to those who will attend for the first time.  The program will feature eight presentations that emphasize crop production, pest management, economics, and the interactions among them.  Please note the program will begin at 8:30 AM and conclude between 3:00–3:30 PM.  Market updates will be provided throughout the day, and communication between speakers and participants is encouraged.  Question and answer sessions are scheduled for both morning and afternoon sessions.  A noon lunch and a proceedings booklet, containing synopses of all presentations, are provided to each registrant.

The dates and meeting locations for the 2015 Corn & Soybean Classics are:

▸ January 7 (Wednesday): Peoria Par-A-Dice Hotel

▸ January 8 (Thursday): Moline iWireless Center

▸ January 9 (Friday): Malta Kishwaukee College

▸ January 12 (Monday): Springfield Crowne Plaza

▸ January 13 (Tuesday): Champaign I Hotel and Conference Center

▸ January 14 (Wednesday): Mt. Vernon Holiday Inn

The following schedule applies to each Classic conference date.  Travel schedules may require a change in the order of speakers.  Program speakers and their respective topics of discussion include:

Jim Angel

Weather Conditions in 2014 and the Outlook for 2015

 

Richard Cooke

Optimizing Drainage Systems to Improve Yields and Water Quality

 

Gary Schnitkey

Crop Economic Outlook and Responses to that Outlook

 

Mike Gray

Inputs and Insect Management: Considerations for 2015

 

Carl Bradley

Getting to Know the Foliar Diseases of Corn

 

Emerson Nafziger

Nitrogen on Corn

 

Aaron Hager

The Best Laid Plans for Weeds by Man Sometimes Go Awry

 

Scott Bretthauer

Evaluating Drift Reduction Technologies for Making Applications of Dicamba and Glyphosate

 

Registration for the 2015 University of Illinois Corn & Soybean Classics is now open and can be accomplished by visiting our conference registration Web site, located at: http://www.cropsciconferences.com.  Advanced registrations, at a cost of $60, are accepted through December 5, 2014.  Registrations received December 6–19 and all on-site registrations are $75.00.  If you have any comments or questions, please feel free to contact us (1-800-321-1296 or 217-244-2124) at your convenience.


Brownstown Agronomy Research Center Cover Crop Field Day – Nov. 13

Mult-species cover crops

Mult-species cover crop trial - Brownstown Agronomy Research Center

 

University of Illinois Extension and the Fayette County SWCD are hosting a Cover Crop Field Day on Thursday, November 13, 2014 from 9:00 – 11:00 a.m. The field day will be held at the U of I Brownstown Agronomy Research Center, 1588 IL 185, Brownstown, IL (Directions here).

The field day will include tours of the current cover crop research trials being conducted at the Center. Extension educators and NRCS field staff will be on hand to discuss cover crop species selection, the effects of planting date and seeding method on cover crop establishment, factors influencing soil health, as will share their experience on the challenges and successes of cover crop establishment. 2.0 CCA-CEU credits in Soil & Water Management have been requested.

For more information, contact:

Robert Bellm,  U of I Extension
618-427-3349  rcbellm@illinois.edu
http://web.extension/illinois.edu/barc

Tony Pals, Fayette County SWCD
618-283-1095, ext. 3  tony.pals@il.nacdnet.net


US EPA Concludes Neonicotinoid Seed Treatments of Negligible Benefit to Soybean Production

On October 15, 2014, the US Environmental Protection Agency issued a report on the benefits of neonicotinoid insecticidal seed treatments to soybean production in the United States. Neonicotinoid insecticidal seed treatments include imidacloprid, thiamethoxam, and clothianidin. The analysis concentrated only on the potential benefits of imidacloprid and thiamethoxam used as seed treatments. Although clothianidin is registered for use as a soybean seed treatment, the authors of the report considered its use “minor” as compared with the other two neonicotinoids. Provided below are interesting pieces of information that I pulled directly from the report.

  • “On average, from 2008-2012, neonicotinoid-treated seeds were applied on 30% of soybean acres, (with some individual years approaching 40% of soybean acres).” page 3
  • Within the Corn Belt (Illinois, Indiana, Iowa, Missouri, and Ohio, 2008-2012) 5, 413,000 and 5,368,000 acres of soybeans were planted with imidacloprid and thiamethoxam seed treatments, respectively. This translates into 433,600 and 151,700 pounds of imidacloprid and thiamethoxam, respectively, used during those years (2008-2012). page 4
  • Across the United States (2008-2012), 1,151,000 pounds of imidacloprid and thiamethoxam were used as seed treatments on soybeans. page 4
  • For this analysis, early-season insects were the primary focus and included many familiar Corn Belt pests such as soybean aphids, bean leaf beetles, cutworms, thrips, and some soil insects (e.g. wireworms, seedcorn maggots). page 5
  • “This analysis provides evidence that U.S. soybean growers derive limited to no benefit from neonicotinoid seed treatments in most instances. Published data indicate that most usage of neonicotinoid seed treatments does not protect soybean yield any better than doing no pest control.” page 13
  • “In cases where pest pressure does necessitate some type of insect control, efficacious alternatives are available for the key foliar pests of soybeans at a comparable cost per acre.” page 13

The authors of this EPA report acknowledge that use of neonicotinoids within soybeans is largely prophylactic — an insurance based form of pest management. In their analysis they estimate that insecticidal seed treatments cost on average approximately $7.50 per acre. They also point out that foliar insecticides labeled for use in soybeans generally cost less than $7 per acre (11 insecticides identified). In addition, the authors of this EPA report make the following assumptions on page 10:

  • “Nearly all soybean growers are already making foliar pesticide applications of some sort and thus have access to the necessary equipment for application. In addition, growers would not have to make an additional field pass as foliar alternative insecticides that target the same pest spectrum as neonicotinoid seed treatments are applied at the same time as a number of current foliar sprays (including herbicides, fungicides, miticides, etc.) and can be tank mixed. No yield gains are expected from neonicotinoid seed treatments, which means the only potential economic impact would be the cost of an insecticide used as a foliar spray.”

Some of these assumptions can be challenged, especially on very large farms across the Corn Belt in which many producers rely upon aerial applications of pesticides rather than making their own ground-based treatments. Additionally, the use of fungicides although increasingly common in recent years, is not routine within every Midwestern soybean field. Therefore, application of an insecticide and fungicide tank mix should not be considered a given on most soybean fields, nor should that of a herbicide and insecticide combination. The optimum time to apply a herbicide for weed control can vary considerably from that to deter insect damage.

Nonetheless, this informative report raises considerable doubt regarding the economic benefits of these insecticidal seed treatments to soybean producers. The use of insecticidal seed treatments within the soybean production system clearly functions as an insurance-based form of pest management. For large commercial farms across the Midwest landscape, many producers typically do not scout soybean fields and utilize economic thresholds to make management decisions for insect pests. Over the years, producers could save on insecticide costs within many Midwestern soybean fields by only treating when economic levels of a given insect pest surface. Yet, the long term trend regarding insect management within large-scale commercial corn and soybean production systems reveals an increasing reliance on product-based inputs (insecticidal seed treatments, Bt hybrids) versus labor and management costs (scouting and use of economic thresholds). It will be interesting to see if US EPA considers a similar analysis for these insecticidal seed treatments in corn production systems.

Mike Gray


Registration Site Open for 2014 AGMasters Conference

The registration site for the 2014 AGMasters Conference is now open! Space in the breakout sessions is limited and those with interest in this conference are strongly encouraged to register at their earliest convenience to help ensure the availability of specialized classes of most interest.The conference will take place at the I Hotel and Conference Center, Champaign, Illinois, December 15 to 16. The registration fee for this event is $250.00 through December 5. Continuing education credits (CCA) are offered in the following categories: professional development (1.5), crop management (4.0), IPM (10.5), nutrient management (1.5), and soil & water management (3.5). The conference begins the morning of December 15 with a general session followed by 16 specialized sessions. Each specialized session is offered twice. Participants will be able to enroll in only eight sessions on a first-come, first-serve basis. Early registrants are most likely to get the eight classes of greatest interest to them.

General Session

  • Marcia Willhite (Illinois EPA) – Illinois Nutrient Loss Reduction: Current Activities-Future Directions
  • Jonathan Coppess (University of Illinois) – Farm Program Decisions in the 2014 Farm Bill
  • Jean Payne (Illinois Fertilizer and Chemical Association) – Reducing Nutrient Losses in Illinois: Owning the Issue to Ensure Non-Regulatory Approaches
  • Rick Weinzierl (University of Illinois) – Evolutionary Principles and On-Going Pesticide Resistance Challenges in Agriculture

Specialized Sessions

  • Scott Shearer (Ohio State University) – Big Data: Discovering the Value of an Underutilized Asset
  • Maria Villamil (University of Illinois) – Working with Cover Crops in Illinois
  • Dean Malvick (University of Minnesota) – Management and Biology of Brown Stem Rot: A Persistent Drag on Soybean Yields
  • Bill Johnson (Purdue University) – Experiences with Palmer Amaranth in Indiana
  • Marty Chilvers (Michigan State University) – Making Every Seed Count: Who’s Responsible for Stand Loss in Corn and Soybeans?
  • Mark David (University of Illinois) – The Science Behind the Illinois Statewide Nutrient Loss Reduction Strategy
  • Matt O’Neal (Iowa State University) – Improvements to Soybean Pest Management: Will this Help Stop the Decline in Bees?
  • Terry Brase (Kirkwood Community College) – Unmanned Aerial Systems: Beyond the Hype
  • Peter Sikkema (University of Guelph – Ridgetown) – Glyphosate Resistant and Problem Weeds in Ontario, Canada-Distribution and Control
  • Damon Smith (University of Wisconsin-Madison) – Integrated Management of White Mold in Soybean
  • Joe Spencer (University of Illinois, Illinois Natural History Survey) – Western Corn Rootworm Resistance: Past, Present and Future
  • Carl Bradley (University of Illinois) – Management of Fusarium Head Blight of Wheat and Associated Mycotoxins
  • Greg Kruger (University of Nebraska) – Back to the Future: Applying Herbicides with Drift in Mind
  • Linda Mason (Purdue University) – How to Get the Most from Your Stored Grain Management Plan
  • Joe Lauer (University of Wisconsin) – Selecting Corn Hybrids in the Transgenic Era
  • Emerson Nafziger (University of Illinois) – Within-field and Within-season Management of Nitrogen for Corn

One of the most popular features of this 2-day event is the opportunity to interact with instructors from many universities in small classroom-style sessions. The instructors have been encouraged to solicit input and questions from the participants. So, please come loaded up with questions for these researchers to address. If you have any questions concerning registration procedures, please contact Sandy Osterbur (saosterb@illinois.edu), one of the Co-Chairs for this year’s program. For additional information about the 2014 AGMasters Conference, please refer to the home page for the event.

I look forward to seeing everyone in mid-December!

Mike Gray, Co-Chair, AGMasters Conference


2014 AGMasters Conference Takes Shape: Plan to Attend

The line up of speakers for the 2014 AGMasters Conference, December 15-16, is beginning to take shape. The 2-day conference will take place at the I Hotel and Conference Center in Champaign, Illinois. The conference begins with a general session that features speakers covering a variety of topics including: potential water protection rules and standards, implications of the new Farm Bill, agrichemical/agribusiness/industry education initiatives, and the practical implications of evolutionary principles regarding resistance development by insects, plant pathogens, and weeds. Following the general session, the program will be devoted to 16 specialized sessions, each repeated once. Topics offered include the following: cover crops, managing big data, refining herbicide application techniques, Palmer amaranth biology/ecology, western corn rootworm resistance to Bt, phosphorus and nitrogen management, understanding and managing Pythium, split applications of nitrogen and phorphorus, white mold and soybean production, Fusarium head blight of wheat, use of drones for aerial scouting, advance in corn genetics, management of insects in stored grain, and soybean management with pollinator considerations. Speakers from a variety of land grant universities will be featured such as: Iowa State University, Michigan State University,  Ohio State University, Purdue University, University of Guelph, University of Illinois, University of Minnesota, University of Nebraska, and the University of Wisconsin.

Specialized sessions are designed for classroom instruction and participation per class is typically limited to 40-45 students. Each session lasts 1 hour. Instructors are encouraged to promote as much participation with the students as possible. The overall number of registrants is limited due to space constraints within the specialized sessions. So, please look for future announcements in this Bulletin regarding registration specifics. This information should be forthcoming in October and an on-line registration site will be provided.

For now, mark your calendars and stay tuned to future announcements. My fellow Department of Crop Sciences co-chairs (Dennis Bowman, Carl Bradley, Aaron Hager, Sandy Osterbur) and I believe we have an outstanding slate of topics and speakers for the 2014 AGMasters! We look forward to seeing you in December.

Mike Gray


ALERT: Fall Armyworms May Reach Damaging Levels in Pastures Across Southern Illinois

Doug Johnson, University of Kentucky Extension Entomologist, has received reports of large densities of fall armyworms in pastures from central Kentucky to the Mississippi River. These infestations follow some large flights of these moths as reported recently by Professor Johnson. The fall armyworm is a tropical insect and the moths migrate to northern states during the late summer and early months of fall. Gulf Coast storms may increase the late summer flights northward. As female moths find grassy or pastured areas, they begin to lay eggs on grass blades. The life cycle (egg to adult) is temperature dependent and takes about 30 to 50 days to complete. Partially grown larvae overwinter in Gulf Coast states. Larvae currently feeding within pastures across southern Illinois counties will not survive hard frosts and the ensuing winter. However, their current feeding can still lead to significant damage to newly-seeded hayfields, pastures, wheat, and double-cropped soybeans. Double-cropped soybeans, if less than R6 stage (full seed) are most at risk when fields are adjacent to severely damaged pastures, especially the rows closest to pastured areas. Injury to plants typically occurs during the morning, late afternoon, or early evening hours. Densities of 5 to 7 larvae per square foot may cause economic damage to stands. Larvae that are 0.75 inches or less in length are easier to control. Those that are 1.25 to 1.5 inches long are the most damaging. Producers are encouraged to scout their pastures, double-cropped soybeans, and newly seeded hay or wheat fields. If fall armyworms are found in damaging levels, producers should consider a rescue treatment paying careful attention to harvest and grazing restrictions for the insecticide that is chosen for use.

Mike Gray


Destructive diseases of soybean – sudden death syndrome and white mold – observed in the state

Signs and symptoms of a few soybean diseases have begun to show up in the last few weeks in some areas of the state.  Two of these diseases, sudden death syndrome (SDS) and Sclerotinia stem rot (a.k.a. white mold) certainly are going to cause economic losses in some growers’ fields this year.

Symptoms of SDS that currently are being observed are interveinal chlorosis and necrosis of the leaves (veins remain green while the tissues between the veins turn yellow and then brown).  These symptoms look exactly like the foliar symptoms caused by a different disease, brown stem rot.  Brown stem rot, however, will cause internal browning of the pith in soybean stems, while SDS does not affect soybean stems.  On SDS-affected plants, the leaves will fall off eventually, while the petioles will remain attached to the stems and branches.  In some cases, a bluish-white mass of spores of the SDS fungus (Fusarium virguliforme) may be observed on the roots.  Although the foliar symptoms of SDS are now being observed, infection by the SDS fungus occurred during the seedling stage, not long after planting.  The symptoms that are now being observed are the effect of toxins that the SDS pathogen produces that are phytotoxic.  Cool and wet weather after planting and the recent rainfall received in parts of the state were favorable for infection and disease development, and are the reasons why SDS incidence is high in some areas this year.  The primary method of managing SDS is to choose the most resistant soybean varieties available.  Some evidence has shown that high soybean cyst nematode (SCN) egg populations may also increase the likelihood of severe SDS; therefore, managing SCN populations through resistant varieties and crop rotation may also reduce the risk of SDS.  Unfortunately, there currently are no fungicide products registered that are effective in managing SDS, but an experimental fungicide seed treatment known as “ILeVO” that is currently making its way through the EPA registration process has shown efficacy against SDS in University of Illinois field trials.

Symptoms of sudden death syndrome of soybean (Photo by C. Bradley).

 

A bluish-white mass of spores of the SDS fungus (Fusarium virguliforme) on a soybean root (Photo by C. Bradley).

 

White mold can be observed in fields located in the northern half of Illinois this year.  The appearance of this disease also is weather-related.  Areas in the northern half of the state, that were cooler and wetter than normal after soybean plants began to flower, are the areas that are affected the most severely.  Unfortunately, once white mold signs and symptoms are detected in the field, fungicide applications generally will be futile, as the damage has already been done.  Management of white mold was discussed in an earlier article of the Bulletin this year (http://bulletin.ipm.illinois.edu/?p=2412).  Growers with severe levels of white mold may encounter some discounts at the elevator this year for high levels of foreign matter.  Some sclerotia (dark survival structures produced by the white mold fungus – Sclerotinia sclerotiorum) that are formed on plants may similar in size to the seed, and will make their way to the hopper and eventually the elevator, where discounts may be received.

 

Soybean plants dying prematurely because of white mold in a field in Champaign County (Photo by K. Ames).

 

White mycelia of the white mold fungus (Sclerotinia sclerotiorum) on a soybean plant (Photo by C. Bradley).


Preliminary Corn Rootworm Injury Evaluation Results from Illinois’ Trials, 2014

In late July, the annual University of Illinois root “digs” and corn rootworm product evaluation trials were completed. Each experiment was established on plots that had been planted to a trap crop (late-planted corn interplanted with pumpkins) in 2013. The results for three of these studies are presented in the following bar graphs. The charts are arranged with the soil insecticide only treatments appearing in light blue, Bt hybrid only products shaded in orange, Bt hybrids combined with soil insecticides represented by the darker blue color, and the untreated checks shaded in dark gray. Treatment bars that share the same letter do not differ statistically (P=0.05).

Most rootworm protection products at the Northern Illinois Agronomy Research Center (DeKalb), were able to keep root injury below 0.5 (1/2 node pruned). Products that resulted in root injury that exceeded this level included: Capture LFR (0.83), Agrisure Viptera 3111 (0.69), Genuity VT Triple Pro (0.92), and Genuity VT Triple Pro RIB Complete (0.9). These treatments were not statistically different from two of the untreated checks. The Agrisure Viptera 3111 treatment expresses the mCry3A rootworm protein along with some other proteins (Cry1Ab, Vip3A) designed to provide lepidopteran control. The Genuity VT Triple Pro and Genuity VT Triple Pro RIB Complete treatments express the Cry3Bb1 rootworm protein as well as some other Bt proteins (Cry1A.105, Cry2Ab2) for lepidopteran pests.  With respect to the checks, three were treated with insecticidal seed treatments: NK N69Z-GT – Cruiser 500; DeKalb DKC63-35RIB – Poncho 500, and Mycogen 2K591 – Cruiser 250. Seed for the TA617-18 check does not have any insecticidal treatment.

Overall pressure in the DeKalb trial was good with approximately two nodes of roots pruned in two of the check treatments. Under this level of injury, the root protection afforded by Bt hybrids expressing only the Cry3Bb1 protein was not stellar. With the exception of Capture LFR, the soil insecticide (only) treatments offered very good levels of root protection. Overall, the combined use of a planting-time soil insecticide and a Bt hybrid did not statistically improve root protection over that of a soil insecticide used alone.

 

Figure 1. Node-injury ratings for root protection products, Northern Illinois Agronomy Research Center, Shabbona, IL. Planting date - May 8; Root dig date - July 28. Node injury scores - 1 = one node of roots pruned to within 1.5 inches of the stalk (or soil line if roots originate from above ground nodes); 2 = two complete nodes pruned; and 3 = three or more complete nodes pruned. Means for RIB treatments may or may not include ratings for refuge root systems.

 

The past few seasons, corn rootworm injury at the Monmouth location has been low and difficult for us to effectively evaluate product performance. In 2014, root injury in one of our checks (NK N69Z-GT, treated with Cruiser 500) exceeded two nodes (2.18) of roots destroyed. The other check (DeKalb DKC63-35RIB, treated with Poncho 500) had less root injury (1.34). Most of the root protection treatments in Monmouth keep root injury below 0.5 (1/2 node pruned). However, root pruning in several treatments exceeded 1.0 (one node pruned) and included: Capture LFR (1.23), Agrisure Viptera 3111 (1.8), Genuity VT Triple Pro (1.83), Genuity VT Triple Pro RIB Complete (1.07), and Capture LFR + Genuity VT Triple Pro (1.02). Root protection afforded by Agrisure Viptera 3111 and Genuity VT Triple Pro was not statistically different from the untreated check (NK N69Z-GT) and use of both treatments resulted in nearly 2 nodes of roots destroyed. Resistance to the Cry3Bb1 protein has been confirmed in several northwestern Illinois counties and cross resistance with this protein to the mCry3A protein has been confirmed in Iowa. Although not confirmed, it seems possible that the resistant western corn rootworm strain may have affected the performance of these treatments within this trial.

 

Figure 2. Node-injury ratings for root protection products, Northwestern Illinois Agricultural Research and Demonstration Center, Monmouth, IL. Planting date - May 7; Root dig date - July 14. Node injury scores - 1 = one node of roots pruned to within 1.5 inches of the stalk (or soil line if roots originate from above ground nodes); 2 = two complete nodes pruned; and 3 = three or more complete nodes pruned. Means for RIB treatments may or may not include ratings for refuge root systems.

 

As compared with the DeKalb and Monmouth experiments, the overall root injury in the Urbana study was lower with the four checks ranging from approximately 1 to nearly 1.5 nodes of roots pruned. Even with this moderate pressure, root injury in the Capture LFR (0.78) and Genuity VT Triple PRO RIB Complete (0.96) treatments approached one node of roots pruned and were statistically similar to several of the untreated checks. Root injury in the other treatments was generally below 0.5 (1/2 node pruned).

 

Figure 3. Node-injury ratings for root protection products, Agricultural and Biological Engineering Farm, Urbana, IL. Planting date - May 12; Root dig date - July 23. Node injury scores - 1 = one node of roots pruned to within 1.5 inches of the stalk (or soil line if roots originate from above ground nodes); 2 = two complete nodes pruned; and 3 = three or more complete nodes pruned. Means for RIB treatments may or may not include ratings for refuge root systems.

Root ratings were not presented for the Orr Agricultural Research and Demonstration Center located near Perry Illinois due to the low overall injury in the untreated checks (0.29 to 0.76). Each of these experiments, including the Orr site, will be harvested later this fall. A final report of the root injury ratings and yields will be published in the on Target Report. This report also includes product performance summaries for previous years going back to 2004.

I offer my thanks to Ron Estes (Principal Research Specialist in Agriculture, Department of Crop Sciences) and Nick Tinsley (Postdoctoral Research Associate, Department of Crop Sciences) for their important leadership in all aspects of this research.

 

Agricultural and Biological Engineering Farm, Urbana, IL, July 2014.

Mike Gray, Ron Estes, and Nick Tinsley


Rotation Resistant and Rotation Susceptible Western Corn Rootworms React Similarly to Bt Corn

A journal article published recently (July 2014) confirms that rotation resistant and rotation susceptible western corn rootworms are affected by Bt root tissue in a similar fashion. The citation for this article is provided below.

Tinsley, N.A., J.L. Spencer, R.E. Estes, J.R. Prasifka, P.M. Schrader, B.W. French, and M.E. Gray. 2014. Larval mortality and development for rotation-resistant and rotation-susceptible populations of western corn rootworm on Bt corn. Journal of Applied Entomology. doi: 10.1111/jen.12149

Based upon some earlier research, investigators hypothesized that rotation resistant western corn rootworm larvae were able to inflict more injury on Bt root systems than rotation susceptible larvae. In this recent paper the scientists made the following observations refuting this hypothesis: “Rotation-resistant and rotation-susceptible larvae had statistically similar mean levels of mortality and head capsule widths when exposed to both single-toxin (Cry3Bb1 or Cry34/35Ab1) and pyramided (Cry3Bb1+Cry34/34Ab1) Bt corn, suggesting that these two populations do not differ with respect to survival or development when exposed to Bt corn.”

Whether you are concerned about the rotation-resistant or rotation-susceptible population of western corn rootworm, now is the time to evaluate the root protection afforded by your Bt hybrid or planting-time soil insecticide. Signs of potential problems include lodging. However, it’s necessary to dig up lodged plants and wash the soil away from root systems to confirm larval feeding. Previous research has shown that one node of roots destroyed can equate to a 15% yield loss in some years. It’s definitely well worth your time to accurately assess the value of your corn rootworm protection tool.

Mike Gray