The always SPECTACULAR Ben Brown leading a Farm Bill Update in Knox County
Today managing your corn crop requires knowledge of the different growth stages of the corn plant. Growth stage identification is critical for scouting and proper timing of fertilizer and pesticide applications. Throughout the growing season I will discuss the various corn growth stages and management issue at each stage.
R2 – Blister
The R2 (blister) stage occurs about 10 – 12 days after silking. At this stage the kernel is visible and resembles a blister. The kernel is filled with clear fluid, the embryo is barely visible and it is at about 85% moisture.
Kernels are in a rapid period of grain-fill. Rapid and steady grain-fill will continue through R6. If severe stress occurs now or during R3, kernel abortion will occur from the tip of the ear downward. Kernel abortion will continue until the plant has has enough carbohydrates for the remaining kernels.
Silks outside the husk leaves are drying and changing in color from tan to light brown. The silks will naturally detach from their kernels following fertilization.
by: Dr. Mark Loux, OSU Extension
Having to issue a retraction to previous C.O.R.N. article where we thought we had it right is always fun. About a month ago we ran an article that covered the legality of POST glyphosate and glufosinate applications to the LL-GT27 soybean, which is resistant to both herbicides. The issue at that time was the legality of applying a mix of both herbicides, based on questions we had received. Cutting to the quick, our conclusion was that because it was legal to apply the mixture since both herbicides could legally be applied and labels did not prohibit mixing. We were naïve apparently, because that article caused the issue over whether it was actually legal to apply glyphosate to the LL-GT27 soybean to be raised. Since then, ODA, USEPA, and the companies who are the involved registrants have been working to come to a solution that clarifies this issue and keeps us all moving forward toward a resolution. The issue here seems to be this – wording on most glyphosate labels specifies application is allowed to “Roundup Ready” and “Roundup Ready 2 Yield” soybeans, and since the LL-GT27 soybean is not designated as such, those glyphosate products could not legally be applied. After a month of deliberation, the USEPA issued some guidance which took the form of the following:
“Users of pesticide products containing glyphosate should refer to the pesticide product labels of herbicide products containing glyphosate for the specific registered uses on pesticide-resistant crops such as soybeans with glyphosate-resistant trait(s). Regardless of the herbicide product name (brand name), if the label of the glyphosate product states it is for over-the-top (post-emergent) use on glyphosate-resistant soybeans, and it is not otherwise restricted by other label statements/directions for use, it can be used on any soybean that has a glyphosate-resistant trait. However, if the label of the glyphosate product states it is for use on crops such as soybeans, with specific glyphosate-resistant traits by name, then the glyphosate product can only be used on those crop(s) with those traits specifically identified on the label. Ultimately, growers and commercial applicators must comply with the entirety of the pesticide label. Please let us know if you have any questions.”
Questions – yes – excuse us while we look for the head scratching emoji. We can try to interpret in real-life speak. Here’s what it comes down to:
– the important part of the glyphosate label here is the use-specific directions, or the section within the larger “Roundup Ready” part of the label that deals with soybeans.
– If the soybean section of the glyphosate product label does not mention specific genetics by trade name, but just the wording “glyphosate-resistant” or “glyphosate-tolerant”, then it is legal to apply that product to the LL-GT27 soybean.
– if the soybean section of the label restricts use to certain genetics by trade name – “Roundup Ready”, “Roundup Ready 2 Yield”, etc, then it would not be legal to apply to the LL-GT27 soybean.
– if the wording on the label is along the lines of “For Use on Soybeans with the Roundup Ready gene”, or similar wording with other specific genetics, it would not be legal to apply to the LL-GT27 soybean.
Our not exhaustive search through glyphosate product labels indicates that most if not all do not contain any wording about “glyphosate tolerance” in the soybean section, and indicate use is specifically on “Roundup Ready” or “Roundup Ready 2 Yield” or “Soybeans with the Roundup Ready gene”. This includes Roundup PowerMAX, Durango DMA, Abundit Edge, Credit Extreme, and Cornerstone to name a few. Manufacturer reps with a glyphosate product label that varies from this are free to contact us so we know.
The inability to use glyphosate on the LL-GT27 soybean affects primarily growers who bought it for the genetics or other traits and not the LibertyLink trait, who might have planned to use only glyphosate POST. Most of the utility of this soybean on problem broadleaf weeds comes from the LibertyLink trait though (and it’s definitely legal to apply glufosinate POST). There’s plenty of generic clethodim around to help out with grass. We assume label language will adapt over time to take care of the glyphosate issue. We’re not even sure this issue would have come up if we hadn’t tried to clarify the tank-mix legality and stepped right in it. There appeared to be some confusion in the field about this though, with different stories being told, and better to just clear it all up way in advance of the season. Stay tuned for the next chapter. Offer void where not legal. Legality may vary by state. Your mileage may vary. Side effects may include confusion, apathy, anger, and spontaneous profanity.
Source: Iowa State University, (Edited)
As the end of the year approaches and we reflect on the 2018 growing season we need to look at what changes or improvements we need to make in our production plans for 2019. Herbicide resistant weeds are continuing to create problems. New, very invasive and harmful weed species (Palmer Amaranth and Waterhemp) are now prevalent in Knox County. Therefore, a review of the effectiveness of your herbicides program is definitely in order.
To effectively battle these new weed problems, creating a comprehensive, all-encompassing weed control strategy is essential in today production agriculture. Over the next 4 weeks I will share information developed by Meaghan Anderson and Dr. Bob Hartzler at Iowa State University on developing a long-term weed management system.
Last week’s post: Herbicide program development: Using multiple sites of action
This week’s post: Herbicide program development: Using effective herbicide groups
After you’ve started working on a program that contains multiple herbicide groups (sites of action), you need to make sure you’re using multiple herbicide groups that will be effective against your target weeds. For most people, the target weed will be waterhemp. Others may have problems with giant ragweed, horseweed/marestail, or other weeds. Waterhemp is the target weed in my example, but consider what your most problematic weeds are to run through this exercise for yourself.
Things to consider when determining whether a herbicide is effective against your target weed include (1) whether the herbicide is labeled to control the weed and (2) whether your target weed is resistant to the herbicide group.
Let’s look at herbicides as if waterhemp is the weed that causes us the most issues. Here’s a table of herbicide groups used in Iowa crops.
Source: Penn State Extension (Edited)
WHAT A FALL!!! According to the November 26 Crop Weather Report, approximately 14% of corn and 10% of beans still in the field. The average moisture content of corn harvested last week was 17 percent and the average for soybeans was 16 percent, how big of a concern is this?
The weather continues to be unpredictable and give challenges to operators with grain and crops still in the field. Snow and ice over the last couple weeks have just been the latest in a long list of hurdles that growers have had to overcome this season. With some careful thought and planning you can still have a successfully harvest.
Having corn in the field now can be a double-edged sword. The longer it stays out, the dryer the corn will be when harvested, thus decreasing your drying costs. However, there is a higher risk of yield loss the longer the corn stays unharvested. Research on winter corn drydown showed that over a five-year span, corn grain would lose roughly 40% of its moisture between the months of October and December, when left in the field. The tradeoff is that we cannot anticipate the weather. The same study found that a single year yield decreased by 45% and another year decreased by only 5%.
Another concern of unharvested corn could be disease and mold. When discussing disease and mold, snow and ice pose no more danger to your crop than rain does. A positive of this situation is that the lower temperatures could have a limiting effect on pathogens’ ability to incubate or develop. A drawback of having laying snow is an increased opportunity for lodging. This year we have already seen a lot of lodging due to stem rots and adding snow to the mix may increase this risk. The risk of lodging is even further increased when coupled with winter winds and snow and ice to come. The takeaway is that disease and mold issues should not be your largest concern right now.
If you have a large amount of stock rot and lodging, harvesting as soon as possible will be best for a successful harvest. If your corn crop has lodged, one thing to remember is that this is not a usual harvest. Special consideration and care must be taken to get acceptable yields, which means slowing down and using caution. A few other options you have for getting a better harvestable yield are combining in the opposite direction, or “against the grain.” This will allow the head to get under the crop and lift it up. Another option is to use a corn reel. A corn reel is a specialized piece of equipment that mounts on the top of your corn head and uses rotating hooks to lift the corn and allow the head to get under the lodged crop.
The last concern is compaction and rutting of fields … Who Doesn’t Have Compaction Issues This Year?? Compaction will linger for years and will require attention to avoid problems with next year’s crop.
Source: Michael Staton, Michigan State University Extension
Every elevator that receives soybeans has a discount schedule. Discount schedules are important because they communicate how and when various shrink factors and discounts are applied at delivery. Discount schedules vary from elevator to elevator and can be somewhat confusing. This article lists and explains the major shrink and discount factors pertaining to soybeans and provides examples of shrink and discount calculations.
Test weight is a measure of density (mass/volume) and is measured in pounds per bushel. The standard test weight of 60 pounds per bushel is always used to convert the scale weight of soybean loads to the number of bushels contained in the load. This is true even if the actual test weight of the load is lower than 60 pounds per bushel. Therefore, test weight does not impact the number of saleable bushels harvested from a defined area (acre or field). However, most grain buyers will begin discounting soybean loads when the test weight falls below 54 pounds per bushel. Discounts are applied to the gross weight of the load before shrink factors are applied. The only advantage of having test weights higher than 54 pounds per bushel is that the beans will take up less volume in storage and during transportation.