UIUC Field Crop Extension Conferences- Sign up today!

What do you need to know for the 2020 growing season? The University of Illinois will address several key topics at four regional conferences around the state in January and February. The meetings will provide a forum for discussion and interaction between participants, University of Illinois researchers, and Extension educators.

Conference dates and locations are:
Jan. 22 DoubleTree by Hilton, Mount Vernon
Jan. 29 Brookens Auditorium at University of Illinois, Springfield
Feb. 4   I-Hotel, Champaign
Feb. 12 Kishwaukee College, Malta

2020 topics and presenters include:

“It’s Tough Out There: Supporting Farmers and Promoting Mental Health” by Josephine Rudolphi, U of I Department of Agricultural & Biological Engineering

“Illinois Weather Review: A Look Back at 2019 & Expectations for 2020 and Beyond” by Trent Ford, Illinois State Water Survey, State Climatologist

“How Should We Manage Today’s Corn Hybrids?” by Emerson Nafziger, U of I Department of Crop Sciences, Professor Emeritus

“Updates in Field Crop Disease Management” by Nathan Kleczewski, U of I Department of Crop Sciences

“The New Era of Herbicide Resistance… and You Thought the Last Era was Difficult” by Aaron Hager, U of I Department of Crop Sciences

“What’s the Real Deal with Cover Crops & Soybean Cyst Nematode?” by Chelsea Harbach, U of I Extension

Insect Management in Corn and Soybeans” by Nick Seiter, U of I Department of Crop Sciences

Hemp, What Have We Learned in 2019?” by Talon Becker (Mt. Vernon), Jessica Soule (Springfield), and Phillip Alberti (Malta, Champaign), U of I Extension

Certified crop advisers can earn up to eight hours of continuing education credit. Advance registration, no later than one week before each conference, is $100 per person. Late and on-site registration is $120. Register for the conferences online at https://go.aces.illinois.edu/IL2020CMC.

#illinois   #corn  #soybean  #wheat 

 

— University of Illinois Extension


Harvest time is not the time to determine if a disease affected your crop

It happens every year.

A field is about to be harvested and something is awry.  Perhaps the plants are lodged, ears are poorly filled, or pods shrunken.  What happened to my crop?

From a plant disease perspective, it is nearly impossible to provide any useful information to the producer.  Many pathogens that can cause crop diseases are also excellent saprophytes.  That means they utilize dead or dying plant tissues for nourishment.  Consequently, when plants prematurely senesce, these organisms see these plants the same way as I viewed Golden Corral in college- it’s chow time!  As a result, it is common to observe senesced plants in fields with multiple “pathogenic” organisms present in or on tissues.  For example, I recently read a report form the diagnostic clinic where four pathogenic organisms were detected in soybean stems.  Was it organism 1,2,3, or 4 that caused the disease?  All of them?  Was it something else related to the environment that killed the plant and all 4 moved in afterwards?  Therein lies the problem- when plants are dead there is no way to know what killed it.    The most important thing needed to properly manage a disease is a confidant identification of the pathogen and knowledge that it was the cause of reduced plant performance.

This is why it is so important to be checking fields throughout the season.  Assessing the health of the crop while most plants are still green allows you to understand if the issue is related to environment, disease, insects, or some other factor.  During the season, make a point to assess your fields at least 4-5 times throughout the season, from planting through maturity.  Look for plants that exhibit abnormal growth or symptoms.  Send samples to your state diagnostic clinic for assessment.  By doing this, you arm yourself with the information you will need to defend yourself from potential yield limiting diseases in subsequent years.

Don’t be that guy.  Don’t wait until it is dry.


Tips for small grain planting in an odd 2019 field season.

Soon many producers will be starting to plant small grains.  Below is my “Top six” list of important things to consider when planting wheat and other small grains in the coming weeks.

1) Ensure that you remove green bridges at least 10 days prior to planting.  This season, prevent plant acres may have favored the development of grassy weeds and other potential hosts of aphids that transmit barley yellow dwarf (BYDV) virus in small grains.  Aphids acquire BYDV upon feeding, and then can transmit it to susceptible hosts.  This group of viruses has a wide host range, and many grassy weeds, in addition to volunteer small grains, serve as a means for this virus to persist during the summer.  When aphids such as the Bird Cherry Oat aphid (and some others that feed on wheat)feed on these grassy hosts and a fresh field of wheat or barley is planted nearby, they can move into these fields and begin to transmit the virus early in the growing season.  Fall infections of BYDV in wheat and barley result in the greatest  potential yield loss in the following season.  To minimize BYDV, ensure that any weeds are killed 10 days prior to planting.  In addition, other obligate pathogens that require a living host to survive the winter, such as stripe rust, can be maintained on volunteer wheat and native grasses during the summer.  This is another reason to ensure to ensure weeds are burned down prior to planting.

2) Plant after the Hession fly free date.  Some think this insect is a myth, but it can appear on occasion.  However, planting after this date is one way to minimize the window of opportunity for diseases such as the aphid transmitted BYDV, stripe rust, and powdery mildew to impact diseases early in fall growth and establishment.  The earlier infections occur, the more likely you will see yield losses the following Spring.

3) Plant certified seed.  Several diseases can be transmitted on seed.  Minimize potential issues by purchasing high quality, disease free seed.

4) Ensure good soil to seed contact.  The faster your plants emerge from the ground, the less chance you will observe potential issues with seedling blights.

5) Plant after soybeans.  This season the potential opportunity to do this will be limited.  Fusarium graminearum, which causes Fusarium head blight (FHB), grows much less efficiently on soybean residue than corn residue.  Thus, planting behind soybeans can reduce the amount of local FHB inoculum in a field the following season.

6) Select varieties with the highest yield potential and best disease resistance packages for common yield limiting diseases.  Growers should focus on FHB resistance (click here for university ratings) then check leaf blotch ratings.  Other issues that are problematic for you on a local scale should also be considered.

 


Diagrams to help you rate foliar disease on corn

Many in the agricultural community, as well as researchers annually rate corn for disease as a means to assess hybrid response, hybrid effectiveness, or potential disease level on field productivity.  It can be difficult to rain the eye to accurately measure disease on foliage, and differences in the type and size of the structure or lesion associated with the pathogen varies significantly.  The four links below will direct you to disease area diagrams we developed in order to help you obtain accurate disease severity estimates in your fields. The method you use to assess disease severity may differ depending on the overall objective. The diagrams below are cor grey leaf spot, northern corn leaf blight, common rust, and southern rust.  These can be printed, laminated, and taken to the field with you to assist your ratings.

SAD_CommonRust SAD_GreayLeafSpot SAD_NorthernLeafBlight SAD_SouthernRust


New maps for tracking Southern rust in corn (repaired link)

Southern rust is caused by a fungal pathogen that does not overwinter in Illinois.  Instead, it blows in from warmer regions during the growing season.  When conditions favor spread and development of this disease significant damage can occur, especially if it arrives before tasseling (VT).  For more information on Southern rust, check out the Crop Protection Network publication by clicking here.  Yesterday our colleagues detected this disease in Southeast Missouri.  With the hurricane/tropical storm remnant pushing northward, and warm weather forecast, there is a good chance we could see some movement into the Southern / Western  part of the state within the next 7-10 days, and there may be some in Southwest Illinois already.  Scouts should be keeping their eyes out for this disease, as things can escalate quickly.  Suspect samples should be sent to the University of Illinois Plant Diagnostic Clinic for confirmation.  Images can also be sent to me via twitter @ILplantdoc, or email at  nathank@illinois.edu.

We have a new tracking system for rusts in corn that we are using this year.  To access the maps click here.  These maps are very useful for tracking a disease that does not overwinter in the area as it needs to spread, establish, and produce more spores to move, unlike diseases that overwinter on residue, alternate hosts, etc.  That means you can see the disease spread and know if you are at risk for it moving into your area.  If your fields are at a critical point in growth, and the disease is detected nearby, in season management can be considered, and unneeded treatments avoided.  We also have a tar spot map.  This disease overwinters in the region, and little is known about disease movement and spread within a season.  Data indicate it can move at least from field to field; however, after last season there is reason to believe it may move longer distances, but we simply are speculating at this point.  This map therefore can tell you when the disease is starting to be detected in certain regions, and also if the disease has been detected in new counties.  For more on tar spot click here.

Locations where tar spot was confirmed in 2018. This map shows incidence not severity at county level. Severity in general was highest in Northern Illinois and extremely low in central Illinois

 

 


Avoid the cosmic freakout

Today colleagues in Indiana reported tar spot presence in some of their research plots located in North West IN.  They found an extremely low number of stroma (less than 10) when assessing approximately 500 feet of plots.  When you see or read about the report keep a few things to keep in mind:

1) The amount detected was exceptionally low, and not close to the widespread severity we saw early last year.  For example, on  July 5th, 2018, we detected tar spot in DeKalb at 100% incidence (every plant had some) with an average of 6% severity at the ear leaf at VT.  Those were wet fields, closed canopies, and a history of moderate tar spot.

2) It will be hot and dry for the foreseeable future.  Tar spot likes moderate temperatures and persistent humid conditions.  In corn that is still in the early vegetative stages, the persistent levels of humidity the pathogen likely needs to sporulate, then transfer those spores to plants, germinate, and infect, might not be met.  Last year at this time our fields in DeKalb and Monmouth were at or approaching VT around this time.  This season we are at V6 and V7, respectfully.  There is not much canopy to retain moisture, especially when conditions 3 weeks ago were favorable for disease onset.

3) Continue to scout, but be aware that the majority of the chatter out there about tar spot being detected in the Midwest is based on misdiagnoses of insect frass.  Spraying poop with fungicide is not going to benefit your crop.  Click here for more information on that particular issue.  If you have any suspect samples, send them to the UI plant diagnostic clinic, send me images, and let us know the approximate location of the putative detection.  We are collecting samples as we did last season.

4) We have observed tar spot in Illinois every year since it was first detected.  This disease overwinters in the region, just like grey leaf spot, white mold in soybeans, and Fusarium head blight in small grains.  Last year was the first time that the disease was severe enough to cause yield loss.  Detecting it is not uncommon.  When it arrives and the amount of symptoms expressed during critical periods of grain fill is what is most important.  Last year was the perfect storm of susceptible crop, environment conducive to disease for a prolonged period of time, and infection during a period critical for yield.  We will observe it this season, the question is when, and how severe and widespread it will be.

5) Fields at highest risk for tar spot will be no till, corn after corn fields experiencing moderate temperatures and persistent humid conditions, and had tar spot last season.  Our collaborative research team has preliminary data indicating that any infested residue on the surface of fields can produce viable spores.  Tillage may potentially reduce the overall number of spores available for local infection of a particular field by reducing the amount of surface residue on the field, but there is no reason to expect the act of tillage alone to impact survival and viability of spores produced on the residue remaining on the field surface.  Planting into fields that were soybean last year may reduce initial disease onset.  This disease isn’t a rust.  Keep in mind, until we have hard data these are simply assumptions based on experience and similar pathosystems.

6) It is evident that there is a lot that is not understood about this pathosystem and in particular, pathogen biology and ecology.  Our tar spot coalition, which consists of a group of pathologists and breeders from the Midwest and Florida, is working on coordinated trials and collaborative projects to learn as much as possible about this disease in an effective, efficient manner.  We are working hard to help our producers minimize potential losses due to this disease.

In sum, keep scouting, don’t freak out, and stay hydrated- it’s going to get hot out there!

On a side note, I’d be more concerned about the recent report or Southern rust from Southeast Missouri, especially for our #corn growers in the southern portion of the state.  That disease blows around, and with hot temperatures and a predicted hurricane remnant moving in, it could move a bit, especially in some of these late plated corn fields.


RSVP for the Champaign Pest and Pathogen Field Day!

Come to Champaign, Illinois on July 22nd for the first annual field crop Pest and Pathogen Field Day from 9am-noon.  Registration, doughnuts, and coffee will start at 8:30 am. Parking for the event will be available at the Agricultural and Biological Engineering farm on the UIUC South Farm Facility, located at 3603 South Race Street, Urbana, IL, 61802.  Click HERE to register.

Join us to walk research plots and learn about insect and disease identification in field crops, current research on field crop entomology, nematode, and plant disease research, and discuss local and regional production issues with entomology and plant pathology experts from the University of Illinois Department of Crop Science.

Examples of some of topics that will be discussed:

Seed treatments for suppressing soil borne diseases of soybean and corn

Lesion nematodes in corn and soybean

Understanding HG types and resistance to soybean cyst nematode

Current research projects of tar spot on corn

Bacterial leaf streak of corn

Red crown rot in soybeans

Fungicides in crop production

Mycorrhizae in crop production

Corn root worm research

Defoliators in field crops

Thrips and Soybean Vein Necrosis Virus

Understanding residual control of insect pests

Cover crops and insects

and much more!

RSVP today- this is a free field day, bring sunscreen, a hat, and plenty of questions!


Fusarium head blight-assessing FHB in your field and late season considerations

A few weeks ago we wrote an article on how to assess severity of Fusarium head blight (FHB) in small grains as well as some practices to consider that can help improve potential profitability in cases where outbreaks are severe.  Now that symptoms of FHB are starting to develop in the earliest flowering wheat, it is a great time to assess your fields and determine if any considerations for harvest need to be made.  To access the article click here.


Another Look at Soybean Planting Date

As we wait for things to dry out so planting can begin in Illinois, I’ll provide an update on soybean planting date, including addition of some recent data and more detail on what planting date studies are telling us.

Between 2010 and 2018, we ran a total of 30 soybean planting date trials at four sites—Urbana and Perry in central Illinois and DeKalb and Monmouth in northern Illinois. We also ran trials at two southern Illinois sites in some of those years, but wet springs in many cases limited the data amount or quality—poor stands from heavy rainfall makes a mess of planting date response—and we generally found there that planting date responses are similar to those in central Illinois.

Most trials included four planting dates, with target date ranges of April 15-20, May 5-10, May 20-25, and June 5-10. When planting couldn’t be done within the target range, later plantings were adjusted; the last planting was later than June 10 in about one-third of the trials. Each trial had four replications, with plots consisted of four 30-inch rows (or seven 15-inch rows) by 25 to 50 ft. long, depending on the location. Two 30” or four 15” rows were harvested with a small plot combine.

We dropped the data from the trials at Perry (Orr Center) in both 2011 and 2012, leaving 28 trials with usable data. In 2011 at this site, yields were low and the last date was very late (June 22), while in the drought of 2012, yield increased with later planting, from only 15 bushels when planted on April 15, to 31 bushels when planted on May 25. That happened because rain that fell beginning in late July was too late for early-planted soybeans, but was of some help to later-planted ones. While we can’t rule out the possibility that this could happen again, including “outlying” data from those two trials had a very large effect on response over all trials, and that lowers the ability of the data to predict planting date response.

We converted the yield data into percent of maximum yield in each trial, then did a regression of yield against planting date and planting date squared, producing a curve that shows acceleration of yield loss as planting date gets later (Figure 1.) Yield loss from planting delays is a little less than I reported previously: according to the curve, planting on May 1, May 15, May 30, and June 10 produced yield losses of 2, 7, 12, and 18%, respectively. At the maximum yield average of 71 bushels per acre, planting on these dates meant yield losses of 2, 4, 9, and 13 bushels per acre, respectively. That’s still a loss, at least at dates later than May 1, but under normal conditions, we can generally plant into mid-May without losing a lot of yield.

Figure 1. Soybean yield response to planting date over 28 Illinois trials. Data are from four sites, 2010 to 2018.

Although fitting a line to the data like we see in Figure 1 shows a small loss in yield for planting on May 1, this line is forced down by the effect of later planting; only once in 25 plantings made before May 1 was yield (at 96%) less than 98% of maximum. This shows that there is little danger of yield loss in soybeans from planting too early, although we didn’t plant in February or March like some have in order to see how yields respond to such “punishment.” This also shows that there’s no real yield penalty from planting in late April or the first few days of May, compared to planting earlier in April.

Planting date studies are not easy to do, and the data from them are somewhat tricky to summarize. Although in this case the data line up relatively well across planting dates, Figure 1 shows that there’s a considerable amount of variability in yield response to planting date, especially at the later dates. As an example, yields from planting between June 1 and June 10 averaged about 85% of maximum, but ranged from 74 to 100% of maximum.

Another way of looking at data like this is to cluster it into groups based on planting date ranges, then to see if the variability is large enough to prevent us from having confidence that planting date within that range had any effect on yield at all. To do this, I broke the data into 10-day planting windows, and ran “descriptive statistics” (using the Excel® spreadsheet) on each group of data to see if variability meant loss of certainty (Figure 2.)

Figure 2. Planting date responses clustered into seven, 10-day planting periods corresponding to the segments separated by vertical lines in Figure. The I-shaped bars atop the data bars show the 95% confidence interval for that cluster of data.

The small I-shapes atop the data bars show the “95% confidence interval”, which is a statistical calculation based on variability among the numbers. Here, if this interval includes 100% (which it does for the first two clusters, April 12-20 and April 21-30), then we can’t say with confidence that the average yield from planting dates in that range is less than 100%. As planting gets later, there’s more variability and so larger confidence intervals, but none of them overlap the 100% line. This means that once we pass May 1, the loss in yield is real, and almost certainly not due to random chance because of high variability.

What’s the point of such an exercise in statistics? In this case, we can see that the line in Figure 1 fits the data points fairly well, but there were still some relatively high yields even with early June plantings. This analysis shows that enough of the data points were low enough that we can’t reasonably expect planting on June 1 to yield as much as planting on May 1, even though that can happen once in a while.

This also illustrates the need for more than one or two studies to give us reasonable confidence that our data predict future responses, which is the whole point of doing such work. Like other factors whose effects depend on weather, planting date studies are notorious for producing widely varying results. So if we had data from only three or four trials, the confidence intervals, which increase in size as the number of points decreases, would likely be so wide that we’d have little idea what to expect when planting late. Or data from only some trials might be selected to make responses look uniform. That creates confidence—“this is what we always see”—but selecting data we “like” is just making up the story. That story might be a nice one, but it’s not one that will help us to know what to expect the next time we head to the field.