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Row Crop Disease Update – Kemerait

CORN- attached picture is sent to me from by our buddy and former agent Eddie Beasley.  Eddie tells me that stunting in this picture is associated with soil counts of both root-knot and stubby-root nematodes in areas of poor growth and vigor.  This image is nearly identical to images sent to me by Rome and Cody Powell.

Back to the image:  NOW, early in the season is a great time to start documenting nematode problems in corn fields.  Carefully digging up the roots and looking for damage, especially nubbed-roots, can be diagnostic.  Best way to confirm is to take two soil samples, one from with the root-zones of stunted plants, the other from the root-zones of “healthy” plants and to compare the results. 

CORN and XYWAY in-furrow fungicide at planting- since my email went out earlier this week, several of you have contacted me to say that farmers have contacted you inquiring about low-vigor or slow-to-emerge corn and that these growers have used XYWAY.  I am grateful that the emails have been helpful.

Remember:  1) Use of XYWAY fungicide in-furrow on corn CAN slow emergence and development.  2) I have very limited experience with XYWAY, but did see this in my trial last year and with Jeremy K. in his trial this year.  3)  I don’t know what the impact on yield will be; stress early in the season like this is not desirable, but I am not sure what the season-long impact will be.  FMC says there is not season-long impact.  I don’t know.  4)  My issue with XYWAY is that it is being recommended for management of diseases (such as leaf blights) that most growers don’t spray for anyway, but could spray for later if they needed to.  5)  My thought is that if a grower contacts you and you think XYWAY is a part of the problem, the best thing to do is to reach out to our friends at FMC (and they are our friends.)

SOYBEAN RUST: Still only found in minute amounts in kudzu in Telfair County.  Apparently Colby Royal (talk about a cool name)  has locked it up there, because we have not found it anywhere else, and we have been looking hard.

PEANUT Early-Season Treatments

I know when I talk peanuts, half of you or more will quit reading, if you have even gotten this far, but in-furrow treatments on the peanut crop is critically important now.  Close the furrow and make the wrong decisions and bad things can happen or you may have spent money you didn’t need to spend.

Question 1:  “Bob, do I have to use a fungicide seed treatment on my peanut seed?”

Answer 1:  “Only if you want to pick peanuts at the end of the season.”

Question 2:  “Bob, which peanut fungicide seed treatment should I use?”

Answer 2:  “Most peanut seed will be treated with Rancona this year because it was more effective in 2020 against pathogens such as Aspergillus flavus and Aspergillus niger than was Dynasty PD.  If, for some reason, your seed is treated with Dynasty PD in 2021, this does not mean you will have a stand problem, it is still a good treatment, but there will be higher risk to stand issues.”

Question 3:  “Bob, does every peanut farmer in Georgia need to use an in-furrow fungicide to compliment the fungicide seed-treatment?”

Answer 3:  “Great question, and the answer is “NO”.  Many growers, especially those with high-quality seed, good rotation, careful planting dates and conditions, do NOT need an in-furrow fungicide.  In-furrow fungicides provide additional stand insurance, that may or may not be needed.  Growers MOST likely to consider use of an in-furrow fungicide product at planting are those who 1) have questions on quality of their seed, 2) are planting saved seed (but not always), 3) growers planting into cool and wet or hot and dry soils, 4) growers who are planting in a field where getting a good stand has been a historical problem, and 5) growers who will just sleep better at night knowing they put one out.

Question 4:  “Bob, what about putting Azoxystrobin out in-furrow?”

Answer 4:  “Azoxystrobin is inexpensive and effective against some important fungal pathogens, especially Rhizoctonia.  It is less effective against Aspergillus crown rot.  As an inexpensive “good but not great” fungicide, I like it.  But, it may not be needed and it does have limitations.”

Question 5, “Bob, in addition to azoxystrobin, what else is there and when would we use them in-furrow?”

Answer 5:  “Glad you asked, see below.”

Peanut nematodes (single row, in-furrow only)  Velum 6.5-6.9 fl oz/A  (Remember “VELUM” is NOT “VELUM TOTAL” and does not include a thrips material.  To control thrips would require coupling Velum with Thimet or imidicloprid, etc.  Also provides additional control of Aspergillus crown rot and some early-season control of leaf spot.

Peanut nematodes (single row, in-furrow only:  AgLogic, 7 lb/A also controls thrips

Peanut nematodes (single row, in-furrow only ) Propulse 13.6 fl oz/A + Velum 1.5 fl oz/A.  Note, this option also covers Aspergillus crown rot, CBR, early season leaf spot and some suppression of early -season white mold.  MUST ADD something for thrips control

CBR and other diseases but not nematodes (single row, in-furrow only) Proline, 5.7 fl oz/A OR Propulse 13.6 fl oz/A.  Propulse is also good on Aspergillus crown rot.

Note:  If you are using Velum or Propulse, there is no need to also include Azoxystrobin, unless there is some reason to be concerned about Rhizoctonia seedling blight.

FOR TWIN ROW Peanuts:  All above rates are cut in half for EACH twin row.  Yes, if effects efficacy, but that is the way it is.

THIMET:  Active ingredient “phorate” is applied to manage thrips, but is also our ONLY in-furrow insecticide that ALSO reduces risk to Tomato spotted wilt.  The protection THIMET provides against Tomato spotted wilt has NOTHING TO DO  with killing thrips (AgLogic and imidicloprid and Orthene do that too) but the THIMET seems to activate natural defense mechanisms in the peanut plant that the others do not.    You DO NOT need to use Thimet to get good control of Tomato spotted wilt, but it makes is a bit easier to do so.  Thimet also provides some early-season protection against leaf spot.  (I didn’t believe it a t first, but it is true.  Just ask Dr. Dan Anco at Clemson.)