Agronomy Talk

Agronomy Update

Fungicides, Insecticides and Disease Development...

Published on Wednesday, July 20, 2016

I have received a number of calls from customers over the past few weeks, so I wanted to provide some updates on a few of the hot topics as we continue to monitor the development of our corn and soybean crops. 

When is the best time to apply fungicide applications on my corn or soybeans to be profitable?

Timing is one of the most important things to consider when making a fungicide application. If applied prior to tassel, you could potentially see some damage to the crop as a result of the adjuvant used. With that said, spraying fungicide between VT and R3 (milk stage) requires diligent scouting and sound decision making. Once fields have reached full tassel stage a fungicide application is safe.  

Beck’s Practical Farm Research (PFR)® has significant data supporting R3 as the best timing to make fungicide applications on soybeans. The R3 growth stage in soybeans is defined as the period at which any one of the top four nodes of the plant have at least one 3/16 in. long pod. With soybeans you can spray as early as R2 (full bloom), but R3 truly is that sweet spot. I know a lot of farmers like to wait until the first of August to make these fungicide applications, but I do not recommend waiting that long. We need to be spraying earlier to control diseases and help fill the pods in the middle and lower portions of the plant more completely. 

What disease pressures are we seeing in corn and soybean fields? 

Fungicide applications on corn typically provide up to four weeks of protection for the plant, so keep that in mind as you scout for disease and make plans to spray. To date, the disease pressure I have come across in my geography has been very low, but can be found if you look hard enough. I have observed some instances of northern corn leaf blight, gray leaf spot and common rust. In addition, insect pressure has been very light, with low amounts of corn rootworm and Japanese beetles. 

When scouting your fields, find the ear leaf and look three leaves below that ear. Are you seeing large lesions? If you planted a susceptible hybrid that has yet to reach R3, have experienced favorable conditions for disease development, and those lesions add up to the size of a quarter or a silver dollar then it may be time to pull the trigger and get out and spray your fields. The top three products I recommend for corn are Headline AMP®, Stratego® YLD or Trivapro®.

Similar to corn, I have noticed very low levels of disease when scouting soybean fields. The most common insects and diseases I have seen to date include septoria brown spot and bacterial blight, which I have found pretty high up on the plant. Unfortunately there’s not much we can do about bacterial blight as it is a result of environmental conditions and is a bacteria that cannot be controlled with fungicide application. However, but we can control the presence of septoria brown spot with fungicide. We want to keep those lower leaves and those in the middle of the canopy as healthy as possible, so be sure to scout diligently and consider a fungicide application when necessary.  

Should I add insecticides to my management plan?

Determining if you should include an insecticide in your management plan will be on a field by field basis. One thing to consider is if the hybrid(s) you planted are fully traited for above ground protection against pests. However, the presence of adult rootworm beetles and Japanese beetles can occur even in fully traited fields, so you will need to monitor them closely. I have not seen high levels of these pests affecting pollination right now, so the inclusion of an insecticide with fungicide in corn is not something I’m recommending at this time.

When it comes to soybeans however, adding an insecticide should be an automatic decision for your program when you’re using a fungicide. We tend to see more positive, consistent returns with the use of both fungicide and insecticide on soybeans than we do on corn.

Should I be applying more nitrogen to my corn? 

The last thing I want to discuss is the uptake of nitrogen (N) by our corn crop. The brown silk stage, or R2, is the stage at which we will see the most amount of uptake in our corn plant. After R2, the root system will shut down and move into a transitional phase. At this time, the corn plant will take everything it stored in the above ground plant tissue and remobilize the nutrition it holds in the stalks, leaves, and tassels and moves it all to the ear. That being said, I don’t recommend applying N after the brown silk stage in corn as there is little to no benefit. The only exception to this would be if we were in a rescue application situation similar to 2015, but we have not been experiencing that level of N loss this year, so an application should not be necessary.  

If you have questions about fungicide, insecticides or even nitrogen uptake in corn please reach out to myself or your local dealer or seed advisor. The most important thing is to keep your crop healthy and protected because there is lot of good yield potential out there right now.











Headline AMP® is a registered trademark of BASF. Stratego® YLD is a registered trademark of Bayer CropScience LP. Trivapro® is a registered trademark of Syngenta Group Company. Practical Farm Research (PFR)® is a registered trademark of Beck’s Superior Hybrids, Inc. 

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Chad Kalaher
Chad Kalaher>

Chad Kalaher

Beck’s Hybrids team sales agronomist for 22 counties in NE ¼ of IL and 7 counties in NW IN. Raised on grain and livestock farm in southern IL. B.S. Agronomy 1995 – University of Illinois, M.S. Weed Science 1997 – North Carolina State University. Previous positions in seed industry as researc

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Full biography

Beck’s Hybrids team sales agronomist for 22 counties in NE ¼ of IL and 7 counties in NW IN. Raised on grain and livestock farm in southern IL. B.S. Agronomy 1995 – University of Illinois, M.S. Weed Science 1997 – North Carolina State University. Previous positions in seed industry as research agronomist, district, and regional sales manager.


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