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Diseases: Cutting costs without cutting yields

Cold, hard truth is diseases and nematodes steal your yield and profit, and newer, often more expensive products, typically are better than older products.

Bob Kemerait, Plant Pathologist

April 30, 2024

4 Min Read
Brad Haire

“Bob, every time you come to talk to us, you have something newer and better and, always, more expensive than what you told us about last year.  How are we ever going to make any money with you around?” 

I hear things like this all the time during the winter meeting season, and I do understand the frustration.  However, the cold, hard truth is that diseases and nematodes steal your yield and profit, and newer, often more expensive products, typically are better than older products. 

For example, a less expensive tebuconazole-chlorothalonil peanut fungicide program in an on-farm study in 2023 was nearly 2,000 pounds per acre lower in yield than was a newer, more expensive program.  That’s why I talk about “newer and better” so much.


Earlier this year, I had a cotton grower tell me he was looking to cut costs, but he didn’t want to “mess up” in doing so.  He told me he had been putting both azoxystrobin and metalaxyl in-furrow under every acre of his cotton.  Azoxystrobin is typically used for management of Rhizoctonia; metalaxyl is used for management of Pythium

When I asked him why he was using the in-furrow fungicides, he told me he had stand issues in previous seasons. At some point in the past the problem had been diagnosed in the field as a combination of soreshin and Pythium damping-off, and it was recommended he use both fungicides.  I wasn’t there at the time of diagnosis, and I don’t want to be a back-seat driver.  However in 24 field seasons in Georgia, I have never once seen a field of cotton that I felt was compromised by Pythium.  I suggested that grower could likely forego the use of metalaxyl and save on that expense.

The phone call came from one of our UGA Extension agents in eastern Georgia.  “Bob, I’ve got growers over here who are trying their best to cut production costs in their peanuts this season, but they don’t want to make a mistake.  They’ve been doing some things for insurance-sake, but are beginning to second-guess themselves. Some of this stuff is going out in-furrow, and they’ve heard you speak, we’ve ALL heard you speak, about the importance of getting it “right” before you close the furrow.  What do we tell them?” 

Fungicide seed-treatments are ALWAYS recommended, no matter whether peanuts, cotton, corn or soybeans.  Today’s commercial seed treatments are often a mixture of fungicides which have activity against a range of fungal pathogens that cause both seed rots and seedling diseases.  In my world these include species of Pythium and Fusarium, Rhizoctonia solani, Aspergillus niger, and Rhizopus stolonifer

The biggest issues surrounding use of in-furrow fungicides and nematicides are that they may, or may not, be needed and that there is only one chance to use them. 

Azoxystrobin is most often used in peanuts and cotton for effective against Rhizoctonia solani.  This pathogen causes post-emergent seedling lost and typically produces a lesion that girdles the young plant just below the soil surface.  Mefenoxam and metalaxyl can be applied when planting cotton for management of pre-emergent seedling disease caused by Pythium

Again, I have never seen a situation where significant stand loss in cotton could be attributed to anything but Rhizoctonia solani or Fusarium in association with nematodes. 

Use of Proline in-furrow is an important tool for management of Cylindrocladium black rot in peanut and, possibly, for some early season white mold control.  Where CBR is an issue, use of Proline is obvious.  Where CBR is not found, use of Proline or Propulse needs to be carefully considered.


The peanut, cotton, corn and soybean crops are all hosts for plant-parasitic nematodes of one type or another.  Growers can place nematicides in-furrow at planting to manage the nematodes and to help protect yields. 

Nematicides include the fumigant (Telone II), granular products (AgLogic 15G and Counter 20G) and liquid products (to include Velum, Propulse, Vydate-CLV and other oxamyl products, and Averland FC).  To get the most out of a nematicide, growers should remember several things. 

First, it is important to have realistic expectations.  As nematode numbers increase, it becomes more difficult for any nematicide to protect yield; however, more effective nematicides will perform better. 

Second, nematicides like AgLogic 15G and Counter 20G require a certain level of moisture for activation. However, because they are water soluble, they tend to dissipate into the soil profile and around the developing root system more than do Velum or Averland. 

Lastly, rates matter and as nematode populations increase, growers should consider increasing rates as allowed by the label.

While I am not 100% sure, I would not be surprised if Bob Seger was talking about farming, fungicides, and nematicides in his lyrics, “What to leave in, what to leave out, against the wind.  I’m still running, against the wind…” 

My advice is to make these decisions based on the best information you can find. Extension is here to help.

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About the Author(s)

Bob Kemerait

Plant Pathologist, University of Georgia

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