Farmer’s Agronomy Update 6-4-21
-Late Planted Corn Reminders
-Head Scab Showing Up
-V6-V8 corn activities
-Late Planted Corn Reminders
Lots of late planted corn that’s yielded better than expected in recent years. Many times we tend to give up on the later planted corn but that is costing us more than some realize and often times I see much bigger returns on our management inputs on late planted corn than I see on the corn planted in our ideal planting window. Here are my thoughts on managing this later planted corn.
-Disease on late planted corn can be a catastrophe, often times our earliest planted corn can outpace some of our worst foliar diseases such as southern rust, however the later planted corn is usually still much earlier in the reproductive and grain fill period when those late season diseases ratchet up to full force, causing a much bigger impact on yield and plant health. It is not out of the ordinary to see foliar fungicide apps on late planted corn have a 40+ bu/ac return vs no foliar fungicide app. With these commodity prices, it should be a no brainer when it comes to foliar fungicide on the late planted corn. In 2019, I had several guys mention they wish they had applied 2 fungicide apps on that latest planted corn, several are in the same replant/late plant boat this year (no pun intended) and are already positioning more product for that additional app. Speaking of that, the foliar fungicide shortage will make it very difficult to find product as we get farther into the season, there are many products that are tight and several that are out of supply, so plan ahead and get possession of it.
-Pests can be harder on late planted corn as well. Corn earworm moths will target the later planted fields in the area as they can sense which ones are later planted by the aroma of chemicals corn plants emit during different growth stages. Generally speaking, the fields south of HWY 50 would be at greater risk but even later planted stuff north of the Missouri River can show increased pressure depending on the year. AML (Leptra) products have increased control on earworm feeding and can be more advantageous in later planted corn, scouting and properly timed insecticide apps would be another possible option. For the non-GMO (conventional corn) fields there is also the added risk of Corn Borer. These fields are also at risk depending on the moth flights and should be scouted intensively and treated timely.
-Nitrogen loss is also a concern where we’ve had heavy rains and warmer soils through May and where we have had some replant or even just late first planted corn. That untreated, fall applied anhydrous would be the most at risk. Remember that with this later planting you have pushed your corn crop’s nitrogen uptake window later in the season and you will need to make up some of that loss with some additional nitrogen. Also any uptake already occurring from weeds or failed first plantings could be tied up for quite awhile too depending on the rest of the season and management. Make sure you adjust your nitrogen plan accordingly.
-It should be no surprise that head scab is showing up fairly heavy in many wheat fields across West-central MO. Even some fields where a fungicide app was made, farmers are surprised at the level they’re seeing. In several cases I’ve noticed where we likely applied that too early. Unfortunately, there’s not much we can do about it now. There can still be decent suppression of DON (vomitoxin) in those fields where we had a fungicide app but still see head scab symptoms. Also remember, that just because you have head scab it is difficult to determine the levels of DON that you will see. The rest of this month could determine how bad that is.
-V6-V8 corn is here for that early planted corn. Just a couple of reminders for this stage of the season for that corn crop.
-Great time for tissue testing as we shoot for V6 corn as our usual first tissue sampling timing.
-Sidedress/topdress time is here. Several planes, spreaders, Y-Drop, toolbars etc. are running some additional nitrogen into these corn fields in the area this week. We have likely lost some nitrogen due to the saturated field conditions and warmer soils in May. I prefer applying additional N during this V6-V8 window as we have a better chance of getting it in the roots and in the plant before that peak uptake period. As far as sidedress/topdress options go, incorporating the product is better than broadcasting as you don’t have to rely on a rain to get your additional N down to the roots where the plants can get it. If you broadcast dry urea, I like to see it treated/protected. Generally, we get 14 days of protection and we usually have higher chances for a rain in early June to get it incorporated vs later in the month. Another thought on nutrients at this time is the addition of sulfur. I have seen great results utilizing 50-100Lbs/ac of AMS which gets you 12-24lbs/ac of sulfate. We need to be incorporating sulfur into our programs for each crop as we aren’t getting enough back from the atmosphere anymore and this sulfate form is ideal as it is ready for use by the plant. Most folks are blending this AMS in with their Urea to get the sulfur applied with their additional N. For broadcast apps of dry products, watch leaf wetness early in the morning to avoid additional leaf burn, the finer material products, like ammonium nitrate, will cause more burning.
-Herbicide cutoffs are also upon us for some products, (I did not include all the possible herbicides available, always check your product label) here’s the one’s for some of our more commonly used products.
V6 corn: Accent, Hornet, Peak
V7corn: Capreno, Liberty, Realm Q, Resolve Q
V8 corn: Aim, Atrazine, Glyphosate, Halex GT, Armezon PRO, Laudis, mesotrione.