General information on plant disease management

We have posted some new materials (along with cool visual aids) on basics of integrated disease management.  Hopefully this information will be useful to you during this busy meeting season.  Click here to view this post.

 

Remember you can sign up for updates to the Illinois Field Crop Disease Hub

Dr. Nathan Kleczewski Extension Field Crop Pathologist UIUC


Efficacy vs management trials

With meeting season going full blast, you will be seeing a slew of data pertaining to disease management and the efficacy of various disease management products.  We posted some general tips to keep in mind at the Illinois Field Crop Disease Hub that can be viewed HERE.

Remember that you can sign up for Hub updates (Hubdates?) by entering your email information on the main page.

Nathan Kleczewski- Field Crop Plant Pathologist and Extension Specialist-UIUC


2019 Applied Research Results, Field Crop Disease and Insect Management now available

The 2019 edition of our annual report on applied research in field crop disease and insect management can be downloaded at the following link: https://uofi.box.com/v/2019PestPathogenARB

 

Each year, University of Illinois plant pathologists and entomologists produce a summary of the applied research we have conducted to inform disease and insect management practices in Illinois. This information provides a non-biased, third-party evaluation of control tactics such as pesticides and resistant varieties for use in corn, soybean, and wheat.

The 2019 report includes information on the following topics:

  • Surveys of insect pests and soybean cyst nematodes
  • Control evaluations for diseases of corn, soybean, and wheat (including southern rust, tar spot, fusarium head blight, and more)
  • Evaluations of Bt trait packages and soil insecticides in corn and foliar insecticides in soybean (including western corn rootworm, bean leaf beetle, dectes stem borer, and others)

image of the cover of the 2019 applied research report

For questions about the guide, please contact:

Nick Seiter, Field Crop Entomologist | nseiter@illinois.edu

Nathan Kleczewski, Field Crop Plant Pathologist | nathank@illinois.edu


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


Looking for Phyllachora samples on grasses- need your help!

Last year we started a project focusing on determining origins of Phyllachora maydis, the causal agent of tar spot of corn, in the United States.  As part of this project, we need to collect Phyllachora species from different hosts and areas.  Today I went for a lunchtime walk and was able to find Phyllachora spp. on four different grass hosts.  Note the large, somewhat raised stroma that follow the veins on most occasions.  They can have halos around them as well.  If you are walking fields, gardens, parks and happen to come across any putative Phyllachora, please send leaves and seed heads to the UIUC plant diagnostic clinic

Phyllachora stroma following the veins, which is somewhat typical for the genus.  N. Kleczewski

Phyllachora spp. on a senesced grass.  N. Kleczewski

Phyllachora spp. with halos around stroma.  N Kleczewski

at S-417 Turner Hall, 1102 S.Goodwin Ave. Urbana, IL 61801 ATTN Tar spot survey.  We really can use your help in this regard!

Nathan Kleczewski- Extension Plant Pathologist UIUC


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.


Late season tar spot- what is on the horizon?

There has been some chatter about tar spot starting up a bit in Northern Illinois corn fields.

Tar spot risk map as of 9.3.19. Most fields are near or past R5 in many of the areas in question.

However, crops are almost at R5 in many places.  What options do we have and what can you expect?  Check out our new post on the Illinois Field Crop Disease Hub by clicking here.  Remember to sign up at the website for updates and look forward to new materials such as factsheets, images, and guides by Spring, 2020!


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.