Making Input Decisions for Corn Rootworms in 2016 – Check out New Webcast

Producers throughout the Corn Belt are in the midst of harvest operations. However, it’s not too soon to begin evaluating the value of corn rootworm inputs for 2015 and their potential value for the 2016 growing season. Earlier this month, the Plant Management Network posted a new webcast titled Estimation of Efficacy Functions for Products Used to Manage Corn Rootworm Larval Injury. The webcast was created by Dr. Nicholas Tinsley, Postdoctoral Research Associate, Department of Crop Sciences, University of Illinois. The foundation for this webcast was field research conducted over many years and published by scientists from the University of Nebraska, University of Wisconsin, and the University of Illinois.

Tinsley, N.A., P.D. Mitchell, R.J. Wright, L.J. Meinke, R.E. Estes, and M.E. Gray (in press). Estimation of efficacy functions for products used to manage corn rootworm larval injury. Journal of Applied Entomology

During the webcast, Nick Tinsley takes viewers through a logical step by step process in assessing the potential value of inputs (insecticidal seed treatments, planting-time soil insecticides, and Bt hybrids) designed to limit economic losses caused by corn rootworm larval damage. I encourage anyone who is ready to begin making these decisions for 2016 to view this short webcast. It could be time very well spent.

Mike Gray, Professor and Extension Entomologist

Sugarcane Aphid Infestations Worthy of Attention in Southern Illinois Grain Sorghum

On August 10, 2015, Dr. Doug Johnson, an Extension Entomologist with the University of Kentucky reported that the sugarcane aphid, Melanaphis sacchari (Zehntner), was collected in two western Kentucky counties (Fulton County and Graves County) on grain and sweet sorghum. The identity of the aphids was confirmed by Dr. Lee Townsend, Extension Entomologist, University of Kentucky. To date, this aphid has largely affected sorghum producers in several southeastern states as well as Kansas, Missouri, and Texas. Recently, I received calls from growers and representatives of the private sector that some grain sorghum fields in southern Illinois were infested with this pest. Counties specifically referenced included Massac, Pope, and Williamson. Infestations have been observed in fields as far north as those located near Marion, Illinois. These observations are not surprising in light of the recently confirmed infestations in nearby locations in Kentucky. Late-planted sorghum is most at risk to severe yield losses; however, the excessive amount of honeydew created by large densities of sugarcane aphids may create significant harvest difficulties even in earlier planted fields. Several affected fields in southern Illinois have been described as “glazed” over with this sticky material. Plants covered with honeydew can significantly interfere with an efficient harvest. Dr. Doug Johnson provided some good background and management information on sugarcane aphids in a June 2 Kentucky Pest News article.

Currently, the Illinois Department of Agriculture is in the process of requesting a Section 18 Emergency Exemption for the insecticide Transform WG (active ingredient – sulfoxaflor) manufactured by Dow AgroSciences. Efficacy data generated by other states indicate that this product has performed well against sugarcane aphids. However, at this point, a Section 18 Emergency Exemption request has not yet been approved for Illinois by the United States EPA.

Another product that has received some consideration for use against sugarcane aphids is Sivanto (flupyradifurone) 200 SL (Bayer). In Dr. Johnson’s August 10 article, he indicated that this insecticide could be targeted at sugarcane aphids with the manufacturer’s 2ee recommendation. The applicator is required to have a label in hand during the application.

I encourage growers to scout their grain sorghum fields for sugarcane aphids and review the articles that I have referenced that were prepared by Dr. Doug Johnson. Also, I will alert producers as to the status of the Section 18 request.

Mike Gray, Professor and Extension Entomologist, Department of Crop Sciences

Call for Grain Samples, 2015

With funding from the Nutrient Research & Education Council (NREC) we started a project in 2014 to try to get a better idea for how much nitrogen (N), phosphorus (P), and potassium (K) are contained in harvested grain of corn, soybean, and wheat.

In 2014 we tried to get yield level for each sampled field in order to see if yield level affects nutrient content. We found that it did not, and so we dropped the requirement to include yield level (will leave it as an option) and ask only for the county in which the sampled field was located.

We already collected wheat samples for this year, but could use some more from stored grain if that’s available. We also have found a source to get most of the soybean samples we need, though we would be happy to take a few more samples from those who can provide them.

Our main need now is for corn grain samples from across Illinois from the crop being harvested this fall. We request that only one sample be taken from a given field.

Here’s how this works:

  1. Before, during, or (for stored grain) after harvest, send an email to to request a mailer. The email only needs to list the cooperator’s name, mailing address, and how many samples of what grain (wheat, corn, or soybean) are being collected. If the mailing address is in a different county than the field the sample comes from, please indicate what county the sample(s) will be from.
  2. We will immediately send pre-paid mailers to the cooperator. The mailer will include plastic sample bags each with a label containing the cooperator’s name (optional for those who want to receive results) and county. It will have a blank to fill in the yield level (estimated or measured) of the field, but that will be optional this year.
  3. The sample bag is sized to hold about 6-8 oz. of grain, which is all we need. The grain should be dry (at or close to standard moisture) so it keeps well during shipping. Put the bag with grain into the mailer and drop it into the US mail. It will be addressed to go to the UI and we’ll get samples analyzed.

Elevators are a place where samples can be gathered efficiently. We will try to contact elevators directly; if you represent an elevator you can let us know how many corn samples you will be able to collect. With corn maturing rapidly early in September this year, some probe samples should come in dry enough to send, though they may need drying if they’re above 16-17%.

Please email me if you have any questions about this.

Western Corn Rootworm Densities Far Below Average in Illinois Corn and Soybean Fields

As part of a USDA National Institute for Food and Agriculture (NIFA) sponsored grant, surveys of insect pests were conducted in randomly selected corn and soybean fields across 28 counties throughout Illinois this summer. Fields were sampled during two discrete periods: July 27 – July 31 and August 12 – August 24. Within each county, five cornfields and five soybean fields were sampled. Within a cornfield (away from the field edge and end rows), 20 consecutive plants were examined carefully for northern and western corn rootworm adults. In soybean fields, 50 sweeps of a sweep net were made in the field interior and another 50 sweeps were taken at the edge of a field (between the last two border rows). Within each cornfield, one leaf was obtained from one of the 20 corn plants examined for rootworm beetles. Each leaf was tested for the presence of Cry (Bt) proteins that are expressed to limit corn rootworm larval injury to root systems. Provided are the key findings.

  • After examining 5,600 corn plants, only 62 beetles were found. These findings include both sampling periods. The greatest density observed was in Whiteside County where an average of 0.1 beetles per plant was found during the second sampling period. This per plant average is far below the economic threshold of 0.75 to 1.0 beetle per plant commonly used to help make corn rootworm management decisions for the following season if a producer elects to plant corn in that same field.
  • After making 14,000 sweeps in the border rows of soybean fields, no brown marmorated, redshouldered, or redbanded stink bugs were detected. These are species of stink bugs that are likely to increase their numbers in years to come. Fortunately, we have good news to report for 2015.
  • Remarkably, only 5 western corn rootworm beetles were found in the interior of soybean fields after making 14,000 sweeps!
  • Across four sampling regions of Illinois (northwest, northeast, west central, and east central), 81% of the leaf samples tested positive for the expression of at least one Cry (Bt) protein targeted at corn rootworms. Of these positive leaf samples, 75% expressed more than one Cry (Bt) protein for corn rootworms and are often referred to as pyramided hybrids. In southeastern and southwestern Illinois, only 25% of leaf samples tested positive for the expression of a corn rootworm Cry (Bt) protein.

Why are western corn rootworm densities so low?

  • There are several factors that can help explain these low densities such as the heavy spring rains that led to saturated soils at the time of larval hatch (late May and early June) in many fields. Secondly, the significant use of highly-effective pyramided Bt rootworm hybrids is taking a toll on corn rootworm larval survival as well. These two factors along with the use of planting-time soil insecticides on top of Bt hybrids is surely having an effect in the overall suppression of the corn rootworm population in Illinois.

Based on these survey data, can I safely assume corn rootworm pressure in my fields will be lower next year?

  • No.
  • Keep in mind there are no effective rescue treatments available for corn rootworms (larval feeding) in most field situations across Illinois.
  • Secondly, corn rootworm management decisions need to be made on a field-by-field basis. Unless you’ve scouted your fields this season, don’t assume that western corn rootworm densities in your field mirror those described as regional averages in this article.

One of the key take home messages from this report should be the importance of regularly scouting your fields for key insect pests, especially the western corn rootworm. Having reliable scouting information on a field-by-field basis this year could pay dividends next season as producers face input decisions for 2016 in the coming months.

I offer my thanks to Nick Tinsley (Postdoctoral Research Associate, Department of Crop Sciences) and Alex Kaluf (Graduate Research Assistant, Department of Crop Sciences) for their leadership in the planning and conduct of this statewide survey. I also thank Luke Harvey and Tate Estes (Summer Interns, Department of Crop Sciences) for their hard work in sampling fields.

Mike Gray, Professor and Extension Entomologist and Nick Tinsley, Postdoctoral Research Associate

2015 Dixon Springs Ag Center Field Day

The 2015 Dixon Springs Agronomy and Horticulture Field Day presented by the University of Illinois, Department of Crop Sciences will be held on Thursday, August 6 at the Dixon Springs Ag Center.

The research center is located on IL Route 145, near Glendale, IL, 25 miles south of Harrisburg and 25 miles north of Paducah, KY.

Tours will start at 9:00 AM with the final bus leaving at 9:20.  A lunch to follow will be provided by sponsors and UI Extension.

The following presenters will speak about current conditions and management challenges in field crop and horticulture production.

  • Emerson Nafziger: 2015 Cropping Season Challenges
  • Aaron Hager: Weed Management, The Simple Days are Over
  • Angie Peltier: Soybean Sudden Death Syndrome (SDS)
  • Russ Higgins: Factors Contributing to a Healthy Soil
  • Jeff Kindhart: Vertigro Hydroponic Strawberries and High Tunnel Mushrooms

CCA CEUs available.

For more information contact John Pike at 618-695-2441 or by email at


Symptoms of Sudden Death Syndrome Begin to Appear in Soybeans

Last week, symptoms of sudden death syndrome (SDS) began to appear in April 15-planted soybeans at the University of Illinois’ Northwestern Research Center in Warren County. Weather during the 2015 growing season has been favorable for the development of SDS: cool, moist soils after planting and frequent rains ever since. Symptoms began appearing approximately 3 weeks earlier than in 2014.

While the fungus that causes SDS (Fusarium virguliforme) infects roots of soybean seedlings very early in the growing season, foliar symptoms don’t typically appear until after soybean plants reach reproductive growth stages. Foliar symptoms begin with a yellowing of the tissue between leaf veins. This tissue then dies, becoming brown in color with only the leaf veins remaining green. Leaves eventually fall off, while petioles remain attached to the main stem. The earlier that symptoms develop and leaf drop occurs, the greater the potential for yield loss.

100_4431Foliar symptoms of sudden death syndrome (photo: A. Peltier).

While foliar symptoms of SDS can be easily confused with those of another disease – brown stem rot – one need only split the plant length-wise to distinguish the two. Brown stem rot causes browning of the inner-most stem tissue (pith) while stems of plants with SDS remain healthy. Blueish-white spores of Fusarium virguliforme can sometimes (not always) be seen on the roots of symptomatic plants.

fungal growthBluish-white spores of F. virguliforme (arrow) (photo: A. Peltier).

Although the most conspicuous symptoms of SDS occur in leaves, the fungus itself remains in the roots and in the stem nearest the soil line. Foliar symptoms are caused by toxins produced by the pathogen. These toxins are carried along with water to leaves through the xylem tissue. The SDS disease cycle has important implications as far as management is concerned: infection and colonization have long since taken place and there are no mid-season management tools with which to manage this disease. Management decisions must be made before the growing season begins.

The best way to manage SDS is to plant the most resistant varieties possible. Soybean varieties vary considerably in their level of genetic resistance. Seed companies typically provide SDS resistance ratings. To provide impartial SDS resistance ratings to help soybean producers more easily compare varietal resistance among seed brands, teams led by Drs. Jason Bond of Southern Illinois University and Silvia Cianzio of Iowa State University evaluated more than 500 soybean varieties (MGs 0 to V) from 19 different seed companies. Results from these 2014 check-off sponsored trials are posted here. Results from the 2015 trials are to be compiled and released in October in time for producers to use while making their 2016 seed purchases.

Research has also shown that SDS may be more severe in fields that also have high populations of the soybean cyst nematode (SCN). Monitoring SCN populations and planting SCN-resistant soybean varieties can also be important components to managing SDS.

The newest tools available for managing this disease are fungicidal seed treatments labeled specifically for SDS. While a University of Illinois Extension Plant Pathologist, Dr. Carl Bradley (now at the University of Kentucky) and his team conducted several SDS seed treatment trials. In these trials, the active ingredient in ILeVO (fluopyram) showed efficacy against SDS. Other SDS seed treatments are also currently being evaluated.

As the season progresses and we near harvest, check out the Northwestern Illinois Research Center’s Website and Blog for data from our 2015 SDS seed treatment trial and other research trials at this location.


Does Corn Still Need Rescuing?

The 2015 Illinois corn crop continues to develop on schedule, with 75% of the crop having reached silking by July 19. But the crop condition rating continues its steady downward trend, with the good + excellent percentage now at 55%, down from its high of 79% at the end of May. Virtually all of this decline is due to standing water, past or present.

Rainfall frequency and amount has moderated some, but parts of western Illinois have received more than 6 inches so far in July. Growing degree accumulations since May 1 are running close to average for the whole state. With planting a little ahead of normal this year we can expect the crop to reach maturity beginning in early September or even late August.

Soil samples pulled at tasseling at several sites in our NREC-funded N-tracking project show that soil N levels have fallen considerably in recent weeks, to levels at or below 50 lb N per acre in the top two feet. We’re finding that soil N levels tend to go down to 40 to 50 lb and not much below that. That’s in part because roots don’t “find” all of the N that’s there, and in part because the mineralization process continues to release N into the soil. When soil N levels are this low, we’re finding much of the N to be in the ammonium form, which is the form produced by mineralization.

For the crop that is well past pollination, the number of kernels developing per ear is an indicator of maximum yield potential. Crops with badly damaged root systems have in most cases been showing pale or yellow leaves, death of lower leaves, and stunting, and either show no ears at all or have very low numbers of kernels. Their yield potential is low and can’t be improved.

In some cases the crop is only now starting to show loss of green coloryellowing, including lower leaf firing that may be moving up the plant. Some of this is occurring in parts of Illinois that have started to dry out, so where we expected the crop to be starting to recover. This still seems to be occurring mostly in lower parts of fields, where water may have stood temporarily, perhaps several weeks ago.
It seems logical to think that N deficiency developing now in fields where standing water hasn’t been a big concern is due to loss of N finally showing up as the plant continues to take up N. There certainly might be some of that happening. Another possibility is that limitations of the root system from earlier damage are only now showing up, especially as the surface soils start to dry and roots start to draw water from a little deeper in the soil.

Can we know which is the case, and is there anything we can still do about it? Either of the situations might mean the crop could respond to N applied to the surface, as long as the N can get into the plant. Before spending the equivalent of about 10 bushels of corn to apply urea by air, though, it would be good to try to assess the yield potential and to try to figure out if the crop is in good enough condition with enough kernels to make a return on the investment likely. There’s no sure indicator of the potential of the crop to respond, but as a start it should have most leaves still intact and around 450 to 500 kernels developing per ear.

If a decision is made to apply more N to a field, the rate should be restricted to no more than 40-45 lb and the N should be applied as soon as possible. Protecting urea with Agrotain should help reduce volatility, but if urea stays on the surface long enough (without enough rain to move it into the soil) it is not going to get into the plant to do much good anyway. Foliar N (urea-formaldehyde solution) is another possible source of N. The lower rate of N applied (usually 10 lb per acre or less) might be enough to carry the crop until its roots can take up more N from the soil. With any source, the idea is to keep deficiency from advancing; the amount of green leaf area is closely tied to grainfilling rate. Dribbling UAN could work, but getting it into tall corn without delay in fields with wet spots might be difficult.

Even if temporary N deficiency can be relieved by supplemental N applied this late, N will not prove to be the most limiting factor; yield prospects will depend mostly on the ability of the root system to continue to take up water, and along with it some N, through the next month to 6 weeks. Some of the developing N deficiency that we are seeing now may be the result of root systems that are damaged more than we think. In that case even moderate stress as surface soils dry out might send plants into a downward spiral. There’s no good diagnostic for root system intactness, but pulling a few plants might provide a hint. If root systems seem small, shallow, or have darkened areas and dead root tips, the prognosis isn’t great.

Things are looking better in parts of the state or fields where water hasn’t stood recently and where roots are getting some oxygen. Outside the downpours, the weather continues to be good, without high temperatures so far. More low-humidity days would help, but humid days with sunshine are still helping the crop. It’s not 2014, when temperatures this time of year were well below normal. But pollination and kernel set should at least be normal in undamaged parts of fields. Let me know if you see something different.


2015 Field Day July 22 at Orr Ag Center, Perry

The 2015 Orr Center Field Day presented by the Department of Crop Sciences at the University of Illinois will be held on Wednesday, July 22 at the Orr Center, which is located on Route 104 four miles west of the junction of Illinois Routes 104 and 107.

Tours will start at 9:00 AM, by group with the last group leaving by 9:20. The tour will take about two hours, and will be followed by lunch provided by UI Extension.

The following presenters will speak about current conditions and management challenges in crop production and protection.

  • Angie Peltier: Management of Sudden Death Syndrome in Soybean
  • Aaron Hager: To Mix or to Rotate? – Herbicides and Weed Resistance
  • Jake Vossenkemper: Soybean Varietal Maturity and Planting Date
  • Stacy Zuber & Mollie Adams: Do Crop Rotations Affect Soils?
  • Emerson Nafziger: Are We Getting Better at Managing Nitrogen?

For more information call Mike Vose at 217 236-4911 or by email at

Statewide Survey of First-Generation European Corn Borer Confirms Exceedingly Low Population

As part of our on-going USDA NIFA (National Institute for Food and Agriculture) sponsored University of Illinois Extension IPM Program, our research team, led by Nick Tinsley (Postdoctoral Research Associate, Department of Crop Sciences), surveyed 28 counties between June 10 to 22 for first-generation European corn borer injury. The counties and six regions surveyed are listed below.

Regions and Counties Surveyed

Northwestern Illinois: Bureau, Knox, Mercer, Ogle and Whiteside
Northeastern Illinois: Kane, Kankakee, LaSalle, Livingston and McLean
West-central Illinois: Adams, Fulton, Logan, McDonough and Morgan
East-central Illinois: Christian, Clark, Effingham, Piatt and Vermilion
Southwestern Illinois: Bond, Jackson, Macoupin and St. Clair
Southeastern Illinois: Gallatin, Jefferson, Lawrence and Massac

Five cornfields were randomly selected in each county and within each field, 100 consecutive whorl-stage plants were sampled for any signs of whorl feeding or the presence of European corn borer larvae. An action site was sampled for European corn borer moths near each field by making 100 sweeps with a standard insect sweep net. We characterized action sites as dense stands of tall grasses in roadside ditches or nearby waterways. Within these action sites moths congregate and mating occurs.


European corn borer action site.

European corn borer action site.


Remarkably, no European corn borer moths were recovered at any of the 140 locations (28 counties X 5 fields) in spite of making a total of 14,000 sweeps! Of the 14,000 whorl-stage plants examined, only 68 had shot-holing (evidence of first-generation injury). The mean percentage of plants with first-generation whorl feeding by region was very low: East-Central – 0.28%, Northeast – 0.56%, Northwest – 0.64%, Southwest – 0.75%, Southeast – 0.25%, and West-Central – 0.44%.

The extensive use of highly-effective Bt hybrids and the areawide suppression brought about by these transgenic hybrids is the primary explanation for these very low densities of European corn borers. According to USDA ERS (Economic Research Service), the use of “stacked gene varieties” accounted for 88% of the corn grown in Illinois during the current growing season. The stormy weather pattern that enveloped much of Illinois during our sampling efforts also likely contributed to the poor establishment of the first-generation of borers.

During some of my summer meetings, a few producers mentioned they had discovered first-generation borers in their non-Bt cornfields. To some extent, this observation caught them by surprise. Although the overall European corn borer population is down across Illinois, this once prominent insect pest flourished for decades (prior to the widespread adoption of Bt hybrids) in many cornfields each season across the Corn Belt. Where non-Bt corn is grown, European corn borers have the potential to infest these fields and cause losses. Therefore, don’t neglect to scout those fields carefully and be prepared to apply a timely rescue treatment. To date, there is no evidence of field-level resistance development by European corn borers to Bt hybrids. This is a remarkable success story nearly 20 years after the commercial release (1996) of Bt hybrids aimed at this insect.

Mike Gray, Professor and Extension Entomologist






Northern Illinois Agronomy Day, July 9th

The Northern Illinois Agronomy Research Center will be hosting its summer Agronomy Day on Thursday, July 9th in Shabbona. Join University of Illinois Extension specialists and researchers as they address issues pertinent to the 2015 crop growing season.

The program begins at 9:00 a.m. and will finish with a noon meal provided at no cost. It is open to all who wish to attend and there is no registration fee. Certified crop adviser continuing educational units will be available.

More than 40 individual research projects encompassing corn, soybean, wheat, oats and cover crops are under way. Current studies include evaluating crop rotations, date of planting, row spacing, plant populations, crop diseases, variety comparisons and crop nutrient management.

Weather permitting; presentations will take place outside, next to research plots. Guests will be transported by tour wagons. Field topics include:

• Water, Corn, and Nitrogen – Can the 2015 Crop Survive and Thrive? – Dr. Emerson Nafziger, Professor and Extension Specialist, Crop Production
• Field Crop Insect Surveys and Management Update – Dr. Mike Gray, Professor and Extension Specialist, Agronomy Research Center Entomology, and Assistant Dean for ANR Extension Programs
• Herbicide Identification: Crop Injury Symptoms and Weed Control – Dr. Greg Steckel, Research Agronomist, NIARC
• Introduction/Update of the Illinois Nutrient Loss Reduction Strategy – Dr. Mark David, Professor Water Quality and Biogeochemistry, Dept. of Natural Resources and Environmental Sciences
• 2015 Weed Control Challenges – Doug Maxwell Principal Research Specialist, University of Illinois Department of Crop Sciences

The 160-acre Northern Illinois Agronomy Research Center is located north of Shabbona and has been used for crop research since 1948. It is the northernmost research center within the University of Illinois Crop Sciences department that is dedicated primarily to row crop research. Visitors are always welcome.

The research center is located at 14509 University Road, about a half mile east of Shabbona on U.S. Route 30 then then 5 miles north on University Road. Perry Road, which runs from the Steward exit (#93) on I-39 to south of DeKalb, is a quarter mile north of the Center. For more information, contact Russ Higgins at 815-274-1343 or email