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By Staff | May 19, 2017

Spring continues to drag on and the rate and pace of corn and bean planting varies widely across the state and the Midwest. In the last few days I have had the chance to view the crop and pace of planting in an area from extreme northwest Iowa down to St Louis. Much of central Iowa should feel blessed and the majority of the corn is in and either has or is in the process of emerging. Bean planting has been progressing between days and fields that are too wet from the twice weekly rain. And the trend for the first five weeks seems to be rain early and in the middle of the week with fields finally drying enough to permit planting from Friday afternoon through Sunday night before getting rained out.

Stands so far vary widely. From near perfect stands in the low to mid 30s down to mid teens with a sizeable percentage now handicapped by a hard crust and may be impossible for the spike to push through. The cold rain and absorption of cold water soon after planting appears to have caused the tissue damage to the seedling described as cold water imbibitions. We saw many growers recognize the potential for the problem to occur and attempted to resist the urge to keep planting even when a cold rain was predicted. Without any firm guidelines on this cold weather malady all anyone can do is try to compare pros and cons based on individual field drainage, dryer capacity, and the willingness to wait for the soils to dry out and warm up.

The priority will be to get all fields planted for the first time, then scout fields and take stand counts on the fields in questions once the top priority plantings have been made. If the fields don’t dry enough then any insurance could kick in on fields lacking in stand.

Field observations

Currently there are many reports from neighboring states of stands that are or did have problems from the cold soils. For instance in northeast Iowa, the soil temps in late April dropped 12 to 20 degrees over a two day period with much of the areas receiving a cold rain that took the cooler temps down into the germination zone. This was right after there were temps in the high 70s and low 80s. Most operators became cautious due to having heard of cold water imbibitions, where if the first water soaked up by the seed was cold, tissue damage could occur. It appears that some of this did occur in the main corn growing states.

The worst I have seen were stands in the high teens, where there are still plants ready to emerge, but are being trapped by crusted soils. There are also plants that have broken the spike and have lost their push. In Nebraska their IPM report mentioned ‘cross banding’ where a yellow band appears on the emerging plants. Justifiably a good question is “will my plants be affected for final yields?” Warmer weather and sunshine will help accelerate growth and recovery.

Over the state there are still corn fields getting planted for the first time. Given the fact that the soils are now above 55 degrees and likely not going to drop again, seedling growth should not be hindered and their yield potential should be good. For these later planted fields to reach their genetic potential it will be important to monitor their nutritional status. Keep them green and filling as long as possible. Allowing the ‘early death’ to hit them and stop grain fill on August 15or 20 is not an option. Make plans now on how you are going to do this and what products you will be using and who will be supplying them. Obtain tissue sampling bags from your local CCA or crop advisor so you don’t have to play catch up in June.

Lately there have been different crops in which the disease pressure has been so severe that multiple fungicide applications per season have been the rule. Now in a number of cases the usual strobe or triazole products are no longer effective. That leaves the crop advisors looking outside the normal channels of information suppliers for advice on how to control disease problems. In reality the number of mode-of-action families is less than with herbicides. In the last decade only one or two new families of fungicides have been commercialized and row crop agriculture is not where the new ones are targeted initially. Be thinking about what your response might be.


I have scouted fields where my recommendation was to run a hoe over the field and try to adjust it for maximum pressure to try to break the thick crust, freeing up the spikes that are just hitting the bottom side of the crust. If a hoeing would increase stands by 6 to 8,000 plants, then get it done. In many cases the ground is too hard or thick to break with a hoe.

Palmer Amaranth

One thought going through some growers’ minds is that certain government agencies still want to talk about the introduction of Palmer seed through the Pollinator Program without accepting ownership of the problem. When the growers signed up they were given a list of seed providers, where none of the sources had been verified as being able to provide clean seed. This was right before Banvel tolerant varieties were hoped to be introduced. They are wondering if this was just coincidence or orchestrated by someone with a vested interest. Educate yourself and learn to recognize the longer petioles on this new species of pigweed during its early growth stage.

Cover crop destruction

Now with all of the talk of soil health and the increased interest in cover cropping more growers are asking about termination of the cereal rye or other product mix. What might be the effect of these herbicides and other crop protection products on soil health? Has any person or group done any good testing to see what documented effects can be expected on soil health using either the Haney or PLFA analyses, and if they have did they publish their results? It might be time to have this testing done so the information can be used when CCAs make their recommendation. Which group may step up to the plate and perform such work?

Insect issues

The main corn insect to be watching in the near future might be the black cutworm. Moth flights were above average in Illinois late this spring but lower than average in Iowa. The expected beginning cut date is May 20.

In soybeans the usual early insect pest are the bean leaf beetles. They typically target early planted bean fields within two miles of a large treed area or near tall grass CRP. With their keen sense of smell then can detected these individual fields. When all bean planting is delayed and many fields are emerging at once any emerging population gets spread over a wider area. Thus the risk from these is lower than normal. Continue to scout any of your fields near a large wooded area on a sunny day between 10 a.m. through about 3 p.m. Watch for fast moving, spotted, greenish red to yellowish beetles that will dart down cracks in the soil once they detect your presence.

Bob Streit is an independent crop consultant and columnist for Farm News. He can be reached at (515) 709-0143 or www.CentralIowaAg.com.

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