Sometimes chemistries don’t work well together. When one chemical prevents another from working as intended this is known as antagonism. One of the more common instances of this occurring in 2019 is in the case of using clethodium with Dicamba and 2-4D to deal with volunteer corn in soybeans.
In biochemistry, antagonism is the inhibition of or interference with the action of one substance or organism by another. Simply put, clethodium can’t do its job when paired with certain chemistries
There are a variety of elements working against us when we
attempt to control Volunteer Corn while spraying Dicamba:
TTI nozzels create larger droplets which decrease uniform coverage
DRAs in Dicamba load increase droplet size
An absence of AMS in Dicamba load due to regulations
Group 15 chemistries, like Warrant, have also been said to antagonize Clethodim.
3 Keys to Successful Applications:
Crop oil is an absolute must in mix with a Dicamba load. A heavier rate provides a better kill
Enlist nozzles and adjuvants have been shown to work better for clethodim
A spray volume of 20 GPA is ideal
Fusilade doesn’t have antagonism with clethodim and is a possible alternative.
Contact your Co-Alliance Agronomy team member if you’re experiencing frustrations with volunteer corn.
2019 has been a tough year in some parts of the state, with many growers hesitant to invest any more in their crop. However protecting this year’s yield is still important, especially in fields that have experienced heavy rainfall. Late-planted corn can be susceptible to disease due to rapid growth.
Agronomists at Dekalb/Asgrow have had reports of Grey Leaf Spot across the state due to the weather. The presence of Grey Leaf can have a huge influence on yields already in a rough place.
Symptoms of Grey Leaf Spot begin as small, dark, t spots encircled by a thin, yellow radiance. The tissue within the “spot” begins to die as spot size increases into longer lesions. Initially brownish and yellow, the characteristic grey color that follows is due to the production of grey fungal spores (conidia) on the lesion surface. Mature corn grey leaf spot lesions have brown rectangular and vein limited shape.
There’s an easy process for monitoring Grey Leaf Spot and other disease progression, all it takes is a can of spray paint, the more eye catching the color the better, and a flag for marking.
Paint Marking Method
Be on the lookout for symptoms of Grey Leaf Spot when scouting fields.
When symptoms are sighted spray the infected area of the plant with spray paint.
Mark the crop row entrance with a flag.
Return to the marked spot within five days to check the progress of the disease. If the disease has spread past the painted area, note the duration of time passed and how far it has spread.
Contact your Co-Alliance Agronomy team member to discuss what steps you can take to prevent yield reduction to the disease.
With the late planting season, many growers are rightly concerned about if their corn can reach maturity– most easily identified by a black layer forming at the tips of the kernel — before the pivotal first frost date.
However there is good news; studies from Purdue have found that for every day after May 1st, corn hybrids mature in 6.8 GDDs less per day.
Example: a hybrid rated at 2500 GDDs from planting to physiological maturity (kernel black layer) and planted on May 31 reaches physiological maturity in less than 2300 GDDs after planting (e.g., 2500 – (30 days x 6.8)).
While traditional GDU models are unable to take this ‘boosting’ ability into account, the DataOnTouch WeatherView App has the ability to forecast a prediction of GDD accumulation.
Using trend data from the past 20 years combined with Purdue research, WeatherView is able to forecast a predicted first frost date for your area and then chart the GDU your hybrid has gained since it’s plant date. Building on this data, Weatherview offers a prediction on whether or not your hybrid will accumulate enough GGDs to hit black layer before first frost.
How to view GDD predictions in DatatonTouch
Use your account to log into DataOnTouch and enter the WeatherView App
Select your field and weather station from the menus on the black bar on right side of the screen
Select the Trend Data option from the blue bar near the top of the screen
Select you Hybrid and Plant Date from the menus on the black bar the the right side of the screen
The line chart will populate based on the information you have selected. If your hybrid line meets the black layer on the chart before the marked first frost date, your hybrid is predicted to meet maturity.
Each year, WinField United tests 240 hybrids across seed brands to determine response-to-fungicide (RTF) scores. Unlike most seed guides, which base disease ratings on visual observations, Answer Plot data is used to calculate the potential yield response of a fungicide application by hybrid. The trials are replicated more than 200 times to account for different growing conditions and geographies.
Data from WinField
United Answer Plots:
Fungicide Cost: $30.00 Corn Price: $3.50
Low – 8.5 bu/ac $0.25 Mod – 16 bu/ac $26.00 High – 21 bu/ac $43.50
This shows that your variety matters when it comes to ROI on a fungicide application. Below is RTF scores for popular varieties from Co-Alliance:
Don’t see your hybrid above? Here’s a list of Dekalb, Mycogen, and NK scores.
A variety of university and industry research trials have shown that an early corn fungicide application around V5 can help optimize yields. Actual yield benefits can vary based on a number of factors including weather, rainfall, and yield potential of the corn hybrid, but models point to an increased chance of positive ROI from an early fungicide application regardless of planting date. If you planted on time, saturated soil conditions will likely mean higher early season disease pressure. If you planted late, applying a fungicide early could be the difference of developing a black layer or not.
The Disease Triangle
Of the two scenarios below, the scenario on the left has a variety with lower disease tolerance, weather that’s vulnerable for pathogens which results in a higher chance for disease. The scenario on the right has conditions that is not favorable for disease.
The above map shows a prediction for the severity of Grey Leaf Spot on corn using the past 5 years of weather data. As you can see, the wet spring has set the stage for an appearance of the disease across the state with a 100% certainty of at least 20% disease impact.
Modern corn hybrids have incredible yield potential even when planted late IF they are managed for that potential. Modern hybrids produce big yield if they are kept alive to produce that yield.
Wet soil conditions exacerbate crown rot and stalk rots. This year’s crop is likely to suffer from these diseases. Fungicides promote stalk strength and help a plant mitigate some of the consequences of these diseases.
Late planted corn is likely to be exposed to greater foliar disease pressure early. Our moisture patterns will favor the development of foliar diseases earlier than a typical year in terms of crop stage. Therefore a standard tassel application may occur after significant foliar infection has already occurred compromising yield potential.
Soybeans are supposed to have a tap root system. This years planting into suboptimal conditions is likely to result in very poor root health (more fibrous than tap root). This leads to increase stress and risk of greater flower and pod abortion.
Beans are behind physiologically. They will flower earlier with fewer trifoliates than most years. This means fewer leaves – fewer photosynthetic factories – meaning protection is critical. To preserve yield potential we need to protect leaves with fungicides and insecticides or risk leaf loss and less ability to feed flowers/pods, etc…
Diseases like frogeye are already present in soybeans. Favorable conditions could leave to an explosion of frogeye similar to what we experienced last year where it certainly reduced yields.
How can I protect my yield?
Knowledge is power. If you know your hybrids, we can create the contact your Co-Alliance team member to look at the data and determine the best crop protection plan for your fields.