K-State Research and Extension

Two more (Kansas) counties were added to a growing list of Tar Spot confirmed areas across the Corn Belt. Jefferson and Nemaha Counties were added, as were neighboring counties in SE Nebraska (Richardson) and NW Missouri (Platte). To date, most disease pressure is very light, but scouting should continue (follow confirmations at: https://corn.ipmpipe.org/tarspot/)

What now? An excellent synopsis of the current situation is provided in this week’s KSU Agronomy eUpdate from K-State Research & Extension Row Crops Pathologist Dr. Rodrigo Onofre at: https://eupdate.agronomy.ksu.edu/article/update-tar-spot-is-now-active-in-four-counties-in-northeast-kansas-597-6 . It will provide answers to a lot of the questions you are likely mulling over as we prepare to make treatment decisions.

I would also add a couple of additional thoughts/references to consider…

Know What You Have

Some of the black spots on corn leaves are Tar Spot – but likely not all. In the early stages of the disease, bug droppings and other material have a similar appearance to Tar Spot but are not. Check by taking a small bit of moisture on your finger and trying to rub the spot off. Tar Spot will not rub off.

If in doubt, let us know! Images can e-mailed to me at dhallaue@ksu.edu or reach out via any Meadowlark Extension District Office for other submission methods, including The KSU Plant Pathology Lab. Submission can be made through the office or via the lab information included in the article above.

Fungicide Selection – How do I make the best decision?

In the post below is an image of a fungicide efficacy chart courtesy of the Crop Protection Network. It’s a great cross reference of products with efficacy ratings based on input from many of years of plant pathology expertise across the Corn Belt. Check it out before you make a fungicide decision.

When should I apply?

Dr. Onofre outlines suggested fungicide timings in his eUpdate article including a link to the KSU Corn Growth and Development Poster with this statement:

Research has shown that making an application just after first detection and at or after VT is effective if lesions are detected early. If you wait until there is significant disease in the upper canopy, a fungicide application may be too late.

Want additional information on application timing? This article from Dr. Mandy Bish at the University of Missouri is a good one: https://ipm.missouri.edu/croppest/2024/6/tar_spot-mb/?fbclid=IwZXh0bgNhZW0CMTEAAR1Veg8A-w90opxILQYOk5_GLw-dFxbF0AJ74fELPskmX9u8Xha2W-gb9mo_aem_ZmFrZWR1bW15MTZieXRlcw . She shares information from a study that separates application timing differences between seeing a yield response and seeing a return on investment to the application.

Keep in mind: you have +/- 12 days from silking (R1) to blister (R2) and by three weeks after silking you are at R3. That seems like a wide window – until it’s not. Plan accordingly!

Are Other Diseases a Concern?

They sure could be and fungicide application timing needs to be considered in light of pressure from those other diseases as well. Scouting will be important to stay ahead of damaging levels of Gray Leaf Spot, Common Rust, and Southern Rust as well – even if Tar Spot doesn’t become a huge issue. NOTE: as of this writing, Southern Rust has NOT yet been detected in the United State according to the Corn ipmPIPE page dedicated to Southern Rust.

Want to Dive Deeper?

• If you want a deeper look into some interesting work comparing early AND late fungicide applications, check out this recent video from Purdue’s Darcy Telenko: https://www.youtube.com/watch?v=qObD-ld9G88 .
• If product efficacy information is of interest, another video from the Crop Protection Network shares multiple years of efficacy information from the fungicide working group: https://www.youtube.com/watch?v=CI62h71g6qQ . The 2023 data starts at around the 20:00 mark.

Tar Spot continues it’s move and fungicide application decisions will soon be upon us. Feel free to reach out if you have any questions!

This is not a map you want to be first on – but here we are. On June 5, 2024, K-State Research & Extension Row Crops Pathologist Dr. Rodrigo Onofre confirmed the first Tar Spot finding of 2024 in corn fields in Doniphan and Atchison County Kansas. This is 3-4 weeks earlier than confirmation in 2023.

Interspersed below are Tar Spot resources to answer some common questions you might have about this challenging disease.

Is this early finding a surprise?

Maybe…but not totally… While this disease continues it’s spread south and west into Kansas, for NEK, even as the timing is earlier than preferred, it’s not completely unexpected. The Corn Belt area affected by Tar Spot has been increasing since 2018 (https://corn.ipmpipe.org/tarspot/historical-end-of-season-maps/) and in Kansas since confirmation in 2022. We now have established pathogen sources in corn residue across much of the NE part of the state allowing this disease to get a start as soon as conditions allow.

What are those conditions:

• 60-75 degree F temperatures
• > 7 hours of leaf wetness
• Irrigation

For some areas of the state, those were certainly the conditions in May…

What were the conditions surrounding THIS confirmation?

See more details in this afternoon’s KSU Agronomy eUpdate, but fields have had a history of Tar Spot. Previous crops were both corn and soybeans.

Should spray applications begin?

Scouting is always a best first option. While I do expect this to be an increasingly common corn pathogen, every field will be different (hybrid susceptibility + previous crop management both affect pressure…). Consider this advice from University of Wisconsin Field Crops Pathologist Damon Smith:

Confirmed levels right now are low. Unless scouting dictates otherwise, fungicide applications are not warranted at this time. Be aware of disease presence. Scout to determine levels in your fields. Plan ahead for fungicide applications should the need arise. 

What products work – which don’t?

There are lots of good products available. One good reference is this report summarizing efficacy research from the Corn Disease Working Group, a consortium of Plant Pathologists from across the country. This excerpt shows ratings for specific diseases (a few Tar Spot ratings outlined in the vertical gray box at right). Efficacy ratings are outlined in the purple box at the top.

NOTE: four years of data from Darcy Telenko (Purdue) and others shows definite efficacy differences among products as well as multiple mode of action products vs. single mode of action products.

Where can I get additional information:

• Fungicide Selection: Fungicide Efficacy for Control of Corn Foliar Diseases [PDF]
• For a deeper look into the disease: Crop Protection Network publication solely dedicated to Tar Spot: https://cropprotectionnetwork.s3.amazonaws.com/tar-spot-filename-2020-05-12-175731.pdf
• Regular Kansas based updates: the KSU Agronomy eUpdate includes a ton of information on numerous topics, and will be a great source of regular updates on the current conditions surrounding Tar Spot for us, including Kansas research results and observations from K-State Research & Extension Row Crops Pathologist Dr. Rodrigo Onofre. Find it here.
• Disease confirmation: suspicious about what you might have? samples are always welcome in the K-State Plant Disease Diagnostic Lab. Information on sampling and submission can be found at: https://www.plantpath.k-state.edu/extension/plant-disease-diagnostic-lab/

Feel free to drop me a line as well via any of our Meadowlark Extension District Offices (contact information at left) or e-mail to dhallaue@ksu.edu. I’ll be posting regular updates and additional information here as might be useful. Best of luck!

If you want a podcast that hits on traditional weed control topics (Herbicide Burndown in No-Till, Herbicide Carryover with Kevin Bradley, etc…) plus a few a little less than traditional (at least for our part of the country…) – A Conversation Between Plants and Weed Control in Mint for example… check out the War Against Weeds Podcast.

Put together by three Extension Weed Management Specialists, including K-State’s own Sarah Lancaster, this is a great podcast that hits on all things weed control. Check it out!

It’s still early in the corn growing season, but at some point – even through the end of the season – we might look at a stand and ask: why am I missing plants or why are some plants yellowing? Even worse: why didn’t this farm yield like we hoped or what caused this lodging? With the myriad of factors that could lead to any of these issues, it can be difficult to pinpoint just one. Complicating things is the amount about crown rots we just don’t understand.

One of the reasons we pay such close attention to soil temperature, utilize seed treatments and make sure we’re planting in good conditions is because of diseases like crown rots. Caused by pathogens including Fusarium, Rhizoctonia, Pythium, or others, these diseases can affect corn plants early in the season with symptoms only noticed until much later. Seed treatments can do an excellent job of combatting them, but when conditions are right for a specific disease to develop (temperature/moisture/seed treatment/etc…), problems can arise.

Continue reading “Crown Rot Pathogens in Corn” →

It’s always a bit of a tricky ‘balance’ when we get spring moisture like we did across NEK this week. We want (need…) it to help with emergence but if it leads to emergence issues (crusting, etc…), sometimes we’d just as soon the plant emerge before moisture arrives. If emergence is an issue, that usually means a deep dive into potential causes. Compaction, residue levels, cold stress, etc… all must be considered. So, too, does the possibility of a soybean seedling disease.

Most soybean seed is treated with a seed treatment that works well enough we often take them for granted. Still, understanding what that treatment is – and what it will combat – is an important part of diagnosing emergence issues when they are attributed to disease. For example, metalaxyl and mefenoxam have activity against diseases like Pythium or Phytophtora – but not Rhizoctonia or Fusarium.

Continue reading “Soybean Seed Treatments – Will They Work?” →

This post is overdue but (hopefully…) signals the end of the alfalfa weevil season for most of NEK. KSU Extension Field Crops Entomologist Jeff Whitworth expressed to me multiple times this season his disdain for this pest. I’m increasingly in agreement as a second year of heavy pressure started early and caused way too much damage. This is an example:

The bad: that’s a lot of damage. The good: the leaves in the upper RH corner surround a pupal case, signifying feeding was likely wrapping up in the southern reaches of the District. This image was from earlier this week along the Nebraska line showing the same in the northern part of the District:

So while the season is winding down, remember: no two fields are the same! This graph shows two fields – neither receiving an insecticide – with increasing weevil levels in one field while numbers declined in the second. More on the multiple reasons why in a future post…

What about insecticide efficacy? I’m hearing mixed reports from growers and retailers alike with this graphic telling a little of the story (no data = sprayed):

The take home: some applications worked really well. Others worked, but maybe not quite as well! The reasons are numerous and I’ll try to share a little of what I’ve gleaned from observations this spring over the next few weeks in preparation for 2025. It underscores Dr. Whitworth’s continued reminder that this isn’t a complex insect – but that doesn’t make it easy to manage!

In my last post, I referenced how growing season weather can effect smooth brome production. Weather isn’t the only factor to consider, however. We know cool season forages respond to good fertility, but did you know there can be fertility/soil interactions as well?

This chart from the Kansas Grazingland Management handbook provides a look at how soil fertility and soil depth affect cool season grass production both independently and in combination with each other (based on animal carrying capacity). Note the differences in productivity based on depth of soil alone – and then how those same stands really thrive under good fertility.

Most of the time we have a pretty good idea of a site’s overall productivity based on management over time. However, if you’re ever working to enhance your grazing management system or troubleshooting a lack of production – a second look at a site’s soil type differences is a good idea. The USDA Websoil Survey (https://websoilsurvey.nrcs.usda.gov/app/ ) is a great place to start. Other grazing productivity sites might have some application as well. Drop me a line if you want to learn more about some of them at dhallaue@ksu.edu.

In a post below, buckbrush management is highlighted. A second multi-stemmed species of concern for us in our perennial forage systems is Roughleaf Dogwood.

One of the challenges with a roughleaf dogwood control program is how much later it comes on than buckbrush. Buckbrush gets to its optimum control window earlier than dogwood, which often doesn’t exhibit its flat-topped clusters of white flowers until late May or early June. In native grass pastures with regular burning, fire can keep it from getting started (see some Konza Prairie control differences in this week’s First Friday Forage Focus on our Meadowlark Extension District Facebook page: https://www.facebook.com/Meadowlarkextensiondistrict ). In cool season forage stands, or unburned warm season prairies, dogwood becomes difficult to remove once established.

Continue reading “Roughleaf Dogwood Management” →

Overview:

As expected, weevil numbers continued their increase over the past week, with every site approaching – or passing – the 50% threshold we often look to for triggering treatment. In fact, multiple sites were sprayed prior to my visits this week and most sites will have seen an insecticide application by early next week.

Resources of interest:
• Treatment efficacy trial results can be found at (lower RH corner of the page): https://www.meadowlark.k-state.edu/crops-soils/index.html .
• Additional pest/production information can be found in the KSU Alfalfa Insect Management Guide: https://bookstore.ksre.ksu.edu/pubs/mf809.pdf

What’s Next?

With most sites likely sprayed over the next week, data next week will likely be limited. Many thanks to the cooperators who have allowed me to check fields and monitor feeding levels.

Scouting will resume post insecticide application to see how products performed – if evaluations can be done prior to the first cutting! In the meantime, drop me a line if you have any questions!

Here are the updated scouting numbers from this week:

The good news is: we DID see at least some small level of mortality from the freezing temperatures this week as the picture below shows. In some fields, there may have been as 5% of these.

The bad news is there are STILL plenty of small larvae still hatching out there. Most of the larvae are very early instars meaning the hatch is probably not over just yet… So, while we got rid of a few this last week, and feeding certainly slowed, there are still numbers to come we need to be on the lookout for. Most fields have yet to reach treatment threshold save for those in the very southern part of the District.

As we reach the 50% threshold often used for treatment, I wanted to reference the KSU Alfalfa Insect Management Guide: https://bookstore.ksre.ksu.edu/pubs/mf809.pdf . It does a nice job of providing active ingredients, rates, etc… As referenced last week, efficacy trials can be found in the lower RH corner of the page at: https://www.meadowlark.k-state.edu/crops-soils/index.html .

The first brush species we typically see in spring is an invasive species known as bush honeysuckle. It’s an issue, but not so much in pasture or rangeland. One that is an early season issue, however, is buckbrush (coralberry). This native perennial spreads mostly via runners, with plants eventually forming dense patches and shading out desirable forage species. Control will require multiple years, and maybe multiple approaches as well.

Continue reading “Buckbrush Management” →

After reports last week of alfalfa weevil infestations in the southern part of the District, our ‘early’ spring was confirmed by the presence of hatched weevil across the area in scouting conducted this week.

Results:
Scouting was done in 9 fields this past week. In each field, I randomly cut 30-70 stems and tried to extract all the weevil I could out of each one. The infestation levels were as follows:

While we did see some level of mortality from the last cold snap, it was by no means extensive. At most, I found +/- 20% dead larvae among the live ones. In most instances, it was difficult to find even one.

Analysis:
Keep in mind a couple of things:
1. Typical ‘threshold’ is 50% or one larvae found/every two stems.
2. Most of these larvae are pretty small so feeding damage still appears fairly light in most cases Continue reading “Alfalfa Weevil Levels – 03/22/24” →

It started a couple of weeks back on social media, but weather this week will increase the conversations even more: why wouldn’t I go ahead and put some beans in the ground?

Arguments can be made for and against early planting (another post for another day…), but what does seem consistent on both sides of the argument is: A soybean that emerges and begins to grow quickly generally tolerates disease/insect pressure better than one in cold, damp soils (if it survives – will it thrive?). Seed treatments are often used to help weather those cooler, damper conditions and while they do a great job, they have limitations. One is the active ingredient(s) in the treatment and what they will control. Another is the length of time they can provide some level of protection (approximately three weeks after planting give or take…)

One handy resource is Fungicide Efficacy for Control of Soybean Seedling Diseases from the Crop Protection Network. It provides some excellent information on various seedling diseases.

It also has some excellent information on seed treatments for a disease that infects the soybean plant early, but doesn’t show up until much later: Sudden Death Syndrome or SDS.

Increasingly an issue for NEK soybean growers over the past decade, SDS has shown the ability to survive not only soybean residue and in soil, but on corn residue as well. It survives our traditional rotations quite well and takes advantage of infection opportunities – most often when seedling development is slowed by cool/wet soil conditions. This graphic from K-State Extension Plant Pathologist Dr. Rodrigo Onofre illustrates some of those optimum infection windows:

While early planting does give us a better opportunity for SDS infection (that is when it’s typically cool and damp after all…), note that we often need a wet period later to trigger the infection symptoms. Its one of the features that makes SDS management difficult because we never know what we’re going to get from a weather standpoint – from infection all the way to visible symptomology.

Since we don’t know for sure what weather might throw at us, we often have to manage SDS in other ways. Start with the seed. Check varieties for SDS tolerance and use high germination seed when possible.

Good planting practices are also key. Research from the Kansas River Valley Experiment Field showed increased frequency of SDS foliar symptomology in narrow row spacings as compared to wider spacings.

Source: Dr. Rodrigo Onofre, K-State Extension Row Crops Pathologist

Because it’s a fungus, fungicide seed treatments have become popular as well. According to the previously referenced fungicide efficacy publication, there are multiple products labeled for SDS control. Unfortunately, many of the ones we might utilize for other diseases are rated poor for Sudden Death Syndrome – if they’re labeled at all. In fact, only two active ingredients – fluopyram and pydiflumetofen – are rated as very good for SDS control. Fluopyram is the active ingredient in ILEVO. Pydiflumetofen is the active ingredient in Saltro.

In 2023, K-State Extension Plant Pathologist Dr. Rodrigo Onofre tested both products in side-by-side comparisons with other seed treatments comparing all to an untreated check. While all seed treatments provide some positive yield difference, ILEVO and Saltro showed the strongest response.

Further evaluation by Onofre confirmed positive reductions in SDS root rot as well, either with Saltro by itself or ILEVO plus Ceramax, a biological seed treatment being tested with hopes of reducing the variability sometimes associated with seed treatments against SDS.

Soybean Sudden Death Syndrome isn’t a problem for every grower every year, tending to be a greater issue in well-managed soybean fields with a high yield potential, particularly when they have a history of SDS. In some cases, variety selection and planting management will keep SDS from being an issue, but if early planting or if planting conditions are favorable for SDS development, seed treatments could be an option to consider.

For more information on SDS management or K-State trials, contact me. Fungicide Efficacy for Control of Soybean Seedling Diseases are available upon request as well.

Alfalfa weevil growing degree days are accumulating fast! Come hear from KSU Field Crops Entomologist Dr. Jeff Whitworth as we discuss what to expect from some warm weather this winter plus hear results from product efficacy trials and application best management practices.

We’ll conclude the morning with a Q & A session open to questions about insects in any of our field crops.

RSVP is due March 4th. Hope you can make it!

This graphic from an Oklahoma State publication paints a good picture of the challenges a small business has when it comes to making transitions.

Agricultural enterprise transitions aren’t exactly the same as small businesses, but with statistics (Purdue) suggesting only 55 percent of farms have a written succession plan, it’s not difficult to see how successful transitions could be a challenge.

If you’re looking at a Farm Transition, check out the Farm and Ranch Transitions Conference March 8th in Manhattan. It will be a great day to learn more about farm transition planning from one of the best in the business: Dr. Shannon Ferrell, Ag Law Specialist at Oklahoma State University.

Registration closes March 1. Get signed up today!

Tis the season for prescribed burns – but there are a lot of questions we should probably be asking first!

• Is weather right? Do we have enough wind to carry a fire, but not so much its dangerous? Optimum conditions usually occur when wind speeds are between 5 and 15 miles per hour with relative humidities in the 50-60% range and temperatures from 50 – 80. What does YOUR fire weather look like? Check conditions at www.mesonet.ksu.edu/fire/rh .

Here’s an example of the conditions for Friday afternoon, February 23, 2024:

Continue reading “Conducting a Prescribed Burn – Are You Planning for Success?” →

Cool Season Grass N Sources

A conversation earlier this week caused me to research brome nitrogen sources. Two things came from that research:

1. Research suggests surprisingly little difference in brome production from year to year between urea and ammonium nitrate if applied at equivalent rates, but…
2. …Big differences can occur if we don’t understand and plan for extenuating circumstances!

It’s by no means an exhaustive review (that may come in time…) but here’s a few thoughts if you are comparing between those two sources: https://www.meadowlark.k-state.edu/news/agent_weekly_columns.html

ARC/PLC Resources UPDATED!

KSU Economists Robin Reid and Jenny Ifft held a webinar earlier today providing some great information on the upcoming ARC/PLC election process. It expands on what I shared here last week to include additional information on the Supplemental Coverage Option (SCO) program available if PLC is your election choice.

Video and handouts can be found at: https://www.agmanager.info/news/recent-videos/managing-risk-arc-plc-and-sco-webinar-slides-and-recording

KSU President Richard Linton’s Regional Community Visit – Holton

Next Tuesday evening, Kansas State University President Richard Linton will be in Holton for the next stop of his Regional Community Visits. They’re an opportunity for he and others to share a little about what’s happening on campus while soliciting feedback from the local community about how Kansas State University might enhance the way it delivers on the land grant mission we are charged with. It will be a time for dialogue surrounding university and community connections with a focus on enhancing partnerships in our region.

The visit is Tuesday, February 6^th, 5:30-7:00 p.m. at the Courtyard Event Center (426 Pennsylvania). If you can make it, please RSVP (by Sunday, February 4^th) at https://kstate.qualtrics.com/jfe/form/SV_1zTfD98K78IKPTo  . Additional information can be found at: https://www.k-state.edu/president/initiatives/regional-community-visits/schedule/jackson-county/ .

Without completion of a new Farm Bill, extension of the 2018 Bill means evaluation of the Agricultural Risk Coverage (ARC) and Price Loss Coverage (PLC) programs at least one more time. March 15th is the election deadline for 2024 harvested crops (payments would be made in late 2025).

The basic program concepts haven’t changed. ARC is a revenue-based program, combining five years of both marketing year average prices and county level yields multiplied by a factor to determine a revenue guarantee. Payments are made if the revenue guarantee isn’t achieved and capped at 10 percent of the benchmark revenue.

The PLC program is more price-based. When marketing year average prices fall below a reference price, payments are triggered. New for this next year is an increase in selected effective reference prices based on marketing year average price triggers set forth in the original bill.

When evaluating your decision, check out the resources available through the KSU Department of Agricultural Economics. The first is a general program overview sharing reference price changes and statewide program election numbers since the inception of the Farm Bill. It’s a great read to get the evaluation process started and includes links to additional resources as well. Check it out at https://www.agmanager.info/arc-and-plc-selections-2024 .

Two of those links will help you take a deeper dive into program options. One is the tradeoff spreadsheet (example below). This Excel based program graphically illustrates where ARC and PLC will tend to pay and when they won’t so you can see differences in each commodity at a county level.

The second is a series of two papers providing marketing year average price outlooks. One provides predictions from KSU economists and explains in greater detail the background on the predictions. The other has predictions from multiple other sources for comparison purposes.

All of the above can be found on the KSU Ag Economics Farm Bill webpage at: https://www.agmanager.info/ag-policy/2018-farm-bill . Want to hear from KSU Economists about some of what to consider? Check out the Managing Risk with ARC, PLC and SCO: 2024 Tradeoffs and Tools webinar Friday, February 2nd with economists Jenny Ifft and Robin Reid. The 12:00 – 1:00 pm Zoom will cover how current market conditions affect these choices plus tools available to help with your decision. Recordings will be available. Register to participate at: https://www.agmanager.info/events/managing-risk-arc-plc-and-sco-2024-tradeoffs-and-tools .

The term ‘soil health’ gets used lots of ways, to the point it can be difficult to define. None of the uses are necessarily wrong, but they might add confusion if you are trying to take a broad look at soil health practices and whether they’re right for your farm.

If you’re trying to get a first look at different practices and how they might change soil health on your farm, consider the Soil Health Matrix Decision Tool. It’s an evaluation spreadsheet put together by 12 regional University Extension partners as part of the North Central Region Water Network (with financial support from North Central SARE) and is designed to provide a way to compare current management practices to the addition of a new or improved soil health practices on your operation. It is not designed to provide an in-depth analysis of soil health measures, but instead a baseline snapshot as to how you might be able to improve soil health with the implementation of various practices.

Continue reading “A First Look At Row Crop Soil Health Practices” →