June 2, 2014
Walking area corn fields you may be a bit surprised at your findings. Despite the recent warm temperatures and rains some Michiana fields are showing quite a bit of early season stress. This stress is fairly normal (if there is such a thing!). It mostly has to do with the roots taking time to catch up with the recent rapid vegetative growth the plant has been doing this last week or so. These symptoms are usually most common with cool, wet soil conditions.
The young root system cannot get enough nutrients to the leaves and so they show signs of deficiency and/or stress. The most common sign of early season corn stress is a purpling of the leaves, which is often a reflection of the roots not getting enough phosphorus to the plant. This is sometimes worse in certain hybrids. Remember this is not because there is not enough phosphorous in the ground – it is because the roots are not mature enough to get all the plant needs into the plant.
Another sign of stress is a yellow striping of the leaves. This can also be hybrid sensitive, but in general is a sign of the plant not being able to take in enough zinc.
As the root system develops and begins to take up adequate nutrients these symptoms will disappear and the corn plant and future yield will be unaffected (assuming there is adequate amount of the nutrient in the soil).
Many areas with heavy soils had problems with the ground crusting. Fortunately most places had a second rain come soon enough to soften the crust enough to let the corn through. The stand was not effected in this instance. (Except where it was too wet to plant all together!)
Watch for weed escapes in corn fields and treat accordingly.
Soybeans continue to emerge. Watch weed pressure carefully and spray weeds while they are still under 6 inches for best control. PLEASE add an herbicide with a second mode of action to glyphosate to ensure control of resistant weeds. Roundup resistant weeds have been found in Michiana. Control of these weeds relies on timely spraying, correct nozzle size and proper tank mixes. Everyone needs to do their part to control these weeds. This means you, by the way! One resistant Marestail plant can produce almost 500,000 seeds! Yikes!
Most hybrids come with insecticide which has greatly reduced the need for rescue treatments, but always look for Black Cutworm and Grub damage in young corn. Black Cutworm can also attack soybean fields, although it is not as common.
Thanks for scouting with us!
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