Category Archives: Corn

Corn Update

Both irrigated and dryland corn are looking okay. Dryland is looking as good as it can. We’ve had less rain as we move east in the county. Corn on the central and west side has had almost an 1nch of rain for the last few weeks. There is rain expected for the weekend also.

This corn is our rust sentinel plot in Thomas County and has only nitrogen burn from foliar fertilizer. You can also see a few spots from Gramoxone drift as we’re planting cotton. None of this is anything to worry about.

We’re past most of our weed control. There are only a few fields where preemergent herbicides didn’t get activated and we’re dealing with pigweed.

Etching done by thrips

Burn from gramoxone

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Field Corn Weed & Disease Update

Some of our earlier planted corn is moving through the v8 growth stage. In this field corn, we are nearly past the time for over-the-top herbicide applications without yield loss. We’ve been applying mostly one shot Atrazine+RU+Prowl H2O when corn has about 3 leaves. It’s working great. We have a one or two fields were pigweed got past it and hurting us.

Weed Control Update

Here is an update from UGA Extension Weed Scientist Dr. Eric Prostko:

Field corn weed control does not have to be difficult.  Just about any of the herbicide programs that growers are using in Georgia do a good job of controlling most weeds, especially Palmer amaranth, when applied to small plants (<3″ tall). Check out the following pictures from my field corn plots that I rated earlier today.  These herbicide treatments were applied 17 days after planting with a CO2-powered backpack sprayer calibrated to deliver 15 GPA at 3.5 MPH using AIXR 11002 nozzles.

The most troublesome weed in Georgia field corn, in my opinion, is annual morningglory.  Field corn growers who struggle with morningglory should seriously consider a post-directed/lay-by application of Evik (ametryn) sometime after their initial POST treatment was applied. (Check out page 70 of the 2017 UGA Pest Control Handbook for more information about Evik.) The minimum corn height for post-directed applications of Evik is 12″.  If Evik is tank-mixed with glyphosate, post-directed applications can be applied up until 48″ tall corn (RR2 hybrids).


Halex+Atrazine+Adept, Dr. Eric Prostko

Atrazine+RU+Prowl H2O, Dr. Eric Prostko

Laudis+Atrazine+MES, Dr. Eric Prostko

Revulin+Atrazine+Adept, Dr. Eric Prostko

Disease Update

This is from UGA Extension Pathologist Dr. Bob Kemerait on 5/1/17:

Our earliest planted corn crop is beginning to approach times where we need to consider use of a fungicide (or not).  Here are some notes…

  1. There is no need at this point to protect against rust. 
  2.  Some growers might put out a fungicide application as early as the V6-V8 stage to protect against leaf blights.  Before doing so (unless the grower simply feels better doing the application anyway) scout for detection of the easily diagnosed lesions of northern corn leaf blight.  Simply finding one or two scattered in the field is NO BIG DEAL. Finding the disease more widely scattered, on a susceptible variety, could be. DO NOT MIX AN ADJUVANT OR CROP OIL with fungicide applications made prior to tassel.  This can result in significant ear deformation.

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Sidedressing Corn

We are very thankful for timely rains without significant storms. We’ve had atleast 1.5″ of rain in the last 7 days. This has helped get our pre-emergent herbicides activiated. This is also good for dryland corn, as it approaches the critical V6 growth stage where much of its yield is determined.

Ground Equipment

It’s not time to sidedress. We want 1.2 lb of total N per bushel goal. UGA Extension Fertility Specialist Dr. Glen Harris recommends sidedressing at 12″ to 16″ height. If we’re using ground equipment, we’re putting out 50 to 75 lbs of N per at at / before planting on irrigated land and 20 to 50 lbs of N per acre in dryland. We put out the rest of the N at sidedressing.


You put out 40 – 60 lbs of N at or before planting and start ground or injected applications of 30 – 60 lbs of N per acre when corn is 8″ to 12″ tall. Keep this going every other week until the total required N is finished. You’ll need 3 to 5 applications during the growing season.


Corn requires about 20 to 30 lbs of Sulfur and we sometimes see sulfur deficiency. It looks similar to N deficiency except we see an overall yellowing of the corn plants. (N deficiency shows up in the lower part of the plant since it is plant movile.) To be sure of which deficiency, we need to take a plant tissue analysis. I talked about the proper way to do this for corn in this blog post.

Only on sandy soils do we split our S applications. Whatever we don’t put out at planting needs to be put out now. Research has shown that we want to correct our S deficiencies between 21 and 30 days old to not hurt yield.

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Corn Coming Up

We looked at a good bit of corn this week that is now coming up in a few different stages. This field was actually planted before our freeze two week back. It slowed germination but would not have any injury. Any corn with just a few leaves – in the V1 growth stage – still has the groing point below the soil surface, which protects the plants from freeze.

We’re just now getting our first herbicide shot, so we’re able to mix Prowl in for grass control. Buffalo grass is all througought this field. Since some grass has already emerged, UGA Weed Scientist Dr. Eric Prostko says it’s okay to add Round Up in with Atrazine + Prowl. It’s one of the best one-shots we have in corn. We had just enough rain last night to help activiate some pre-emergent herbicides.

V1 Growth Stage – The collar (white line) is present on the 1st leaf.

V2 Growth Stage – The collar is present on 1st and 2nd leaf.











At the V1 growth stage, the growing point is still below the surface of the soil. At this stage, three leaves are visible. The leaf collar is only on the lowest leaf. At V2, four leaves are visible, but the collar is only on the 1st and 2nd leaf. At this growth stage, corn water demand is close to 1/10″ a day.


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2017 Corn Short Course – Jan 24th


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January 16, 2017 · 4:26 PM

December Row Crop Disease Update

A few things to think about with regards to disease and nematode management in preparation for the 2017 field season.

La Nina:  Our UGA Extension climatologist Pam Knox has good information available on our current conditions, but here are my thoughts:

We are currently in a “weak” La Nina situation, “weak” because the equatorial waters of the cost of Ecuador are more than a half degree COOLER than normal.  As best I can tell, the waters have been about 7/10 of a degree cooler which barely qualifies as a La Nina (as opposed to last year where we had a robust and sure-enough El Nino).  So what does this mean? During La Nina years, the Southeast tends to (“tends to” means more often than not, but not always..) experience warmer and drier winters. Because we have a weak La Nina, this forecast could change.

Pigweed seedhead in broccoli before Thanksgiving. We are yet to have frost to knock back pigweed growth.

Pigweed seedhead in broccoli before Thanksgiving. We are yet to have frost to knock back pigweed growth.

How does our current “La Nina” impact our recommendations?

  1.  Drier is not a good thing as it may mean we don’t fill up irrigation ponds for next year.  It my mean we have a lot of trouble establishing cover crops this fall.
  2.  Warmer temperatures may mean that kudzu, volunteer peanuts, corn, cotton-regrowth, etc. pathogens (like those that cause soybean rust and southern corn rust) may survive and increase longer than they would with an earlier “killing” frost.  Also, as long as the crops and volunteers are active in the field, nematode populations can continue to increase and build.  This will lead to larger populations for next season. Once the plants are killed, the nematodes can no longer feed. Once soil temps drop below 65F, the activity of the todes drops off as well.
  3.  We may get some very cold weather soon, so we may not need to worry that much; however the general prediction is that we will have a warmer winter.
  4.  The weather this winter will have some effect on TSWV and insects for next year.  It remains to be seen what and how… but it will impact them.

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Filed under Corn, Cotton, Disease, Peanuts, Soybeans, Weather

2016 Update On Stored Grain Protectants

UGA Entomologist Dr. Mike Toews is getting questions about treating shelled corn as it goes into storage. Here is updated information on products and efficacy from my recent tests in Georgia.

Actellic 5E (labeled for corn) – This is the standard product for shelled corn, but it is also the most expensive product to purchase. A full rate (12.3 oz  per 1000 bu) will provide protection from weevils for at least 9 months, but reducing the rate will decrease the longevity of the protection. Actellic is susceptible to heat breakdown.

Centynal (labeled for corn and wheat) – Centynal is fairly inexpensive and will provide 3 to 6 months protection from weevils. It is critical to apply a full rate (8.5 oz  per 1000 bu) or weevil control will be compromised. This material may also be used for treatment of empty bins.

Diacon (labeled for corn and wheat) – Diacon is an insect growth regulator that is effective at killing immature grain moths and beetles, except weevils. The 4 oz per 1000 bu rate is sufficient for tank mixing. 

Storcide II (labeled for wheat) – Storcide II is an excellent option for stored wheat, but is not labelled for use on corn.

Malathion (labeled for wheat and corn) – This product has been widely used in the past, but is not currently recommended due to well documented resistance in many stored grain insect populations.

Tempo SC (labeled for empty bin use only) – Tempo is an excellent material for treating empty bins and elevator boots, but is not labeled for application directly to grain.

Three-way tankmix – Tests from 2015 showed that a three way tank mix of Centynal (8.5 oz) plus Diacon IGR (4 oz) plus PBO-8 Synergist (13.5 oz) will provide 6-9 months of protection from weevils.  This is a moderately priced option for growers in markets where other products arSilose unavailable or cost is a limiting factor.

Regardless of the product used, please be mindful that grain protectants are not a silver bullet. Applications should only be made to cooled grain (do not apply before sending grain through the dryer) that will be stored for more than 3 months.  Apply protectants at the bottom of the auger so the kernels have a good chance to contact the insecticide while moving up to the top of the bin.  Long-term grain storage also requires grain at an appropriate moisture content, proper housekeeping, use of a spreader when filling bins, and managed aeration.

Additional information is available in the 2016 Georgia Pest Management Handbook or in a recent Extension Publication ( that Dr. Kathy Flanders at Auburn University and I authored earlier this year.

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