As we approach a potential late harvest, the effects of drought on the corn crop in southern Iowa, South Dakota, and other areas in the Midwest are evident. Concerns include ear tip back and potential stalk lodging. On the positive side, many areas of East Central and NE Iowa, N. Illinois, Wisconsin and Michigan have gotten enough rain and crops are excellent, assuming we get enough time to mature the crop before frost. Corn rootworm beetles have been a concern in some fields, especially in continuous corn fields, while Japanese Beetles were troublesome in many areas in both corn and soybean fields. Refuge and conventional corn showed some European Corn Borer damage, but generally less than 2016. This may be a bad year for earworm, unless protected by the Agrisure Viptera® trait.
This year Common Rust is present in many fields, and we have seen the start of Grey Leaf Spot (GLS). Northern Corn Leaf Blight (NCLB) has been slow to develop in Southern and Central Iowa, partially due to warmer temperatures, however I have seen some NCLB in Northern Illinois, where it was cooler and wetter. Due to the recent moisture and humidity, I expect this will be a year with a high incidence of disease, including GLS. It also is a year where leaf tissue is at a premium, due to smaller total leaf area than normal. I am inclined to apply Headline AMP® or a similar fungicide in most corn and bean fields this year. I especially would consider applying fungicides to fields with high residue, fields following cover crops, corn-on-corn fields, low lying fields, or poorly drained fields. I also would apply fungicide to hybrids which are more fungicide responsive for yield and standability. A greater economic advantage exists for fungicide application, if you already need to apply an insecticide. We feel the ideal time to spray a fungicide on corn is around the first brown silk. However if CRW or Japanese Beetle clipping of corn silk occurs, I would apply the fungicide with an insecticide during flowering. Avoid using an adjuvant if applying fungicide before full silk.
Soybean diseases could be prevalent this year in areas with excess rain and fungicidal control may be justified, because we must preserve the limited soybean leaf area in 2017. White mold (WM) could be a problem in wetter fields, but WM may be reduced this year, as it appears soybeans could breathe better since soybeans are generally not be as big as normal.. Due to the high level of SDS last year, continue to monitor fields that are wet during early flower for SDS. SDS management involves seed treatments (Clariva® and ILevo®), improved drainage, and planting highly tolerant varieties such as 3155CRR2 and 2659CLL. We focus heavily on launching improved SDS and white mold soybean varieties.
Insects in corn and soybeans are considerable in some fields this year due to the mild winter. Many Japanese Beetles, and in corn-on-corn fields, a lot of Corn Rootworm (CRW) beetles have been observed this year. Be sure to scout at silk emergence in later planted or variable emerging fields to determine if there is a need to spray insecticide to prevent silk clipping and pollen feeding. If an insecticide is needed, we suggest combining it with a fungicide application due to the current ideal conditions for disease development. This is also a key timeframe for Western Bean Cutworm (WBC) flights. WBC can be quite damaging to the yield and grain quality unless you spray or have genetic control, such as Agrisure Viptera.
We are concerned about the high number of Japanese Beetles feeding in soybean fields as well, especially since many beans are smaller than normal because they struggled with a slow start due to often being too wet around planting and then before roots were well established it often turned off dry.
It also is a good time to do root digs to observe any rootworm feeding. Let us know by the end of July, if you planted Miller Hybrids corn containing a rootworm trait that did not adequately control corn rootworms, as there may be credit given to you from the genetic trait provider.
2017 has been another typical year of extreme weather in the Midwest.
We were generally cooler than normal and wet into late May, with SE Iowa having a drier than normal June and early July, although rains came to many areas July 9 and 10. Disease development was initially slow, but because of recent rains, conditions are now favorable for disease. Corn fields planted in April tended to be a little more erratic in emergence and often are 10% lower in population than normal. Corn planted early, generally rooted down and pollinated well, although the corn is often 20% smaller than usual. Corn planted in mid to late May, could struggle to pollinate well, due to the hot night time temperatures forecast for July 18 to 21.
Carefully monitor weed pressure and try to spray corn for weeds before they exceed 4” tall, as weed pressure can have a dramatic impact on potential corn yield.
If using Liberty herbicide, use drops if corn is above knee high. A good herbicide with residual control of waterhemp is recommended. If you used Glyphosate “GT or RR” tolerant corn last year which did not contain Liberty Tolerance and this year you have Liberty tolerance in your corn, spray Liberty now to remove volunteer corn (VC) as VC can significantly affect yield and rootworm control, even in corn carrying the RW gene.
Miller Hybrids is one of only a few companies that continue to carry elite Liberty Link corn.
Agrisure shared some great slides to help explain a few things about their products. Check it out...
The many windy days we have experienced may have brought disease spores from the South and although we are currently in a dry spell, disease spores are prevalent in decaying tissue. Be sure to continue to scout and monitor disease favoring conditions, once this dry spell breaks.
Fungicide costs are down significantly from a few years ago and most of our top producers have seen a nice return on investment by using fungicides. This is especially true in high yielding fields that are either corn-on-corn or which are planted to conventional corn.
Low lying fields are more vulnerable as well as fields planted to less disease susceptible varieties. Insecticides can be mixed with fungicides, but it is important to follow the correct protocol for fields near beehives.
Images courtesy of Google Image Search
There are questions about the corn height this year being shorter than normal for corn planted in April. This appears to be the case due to at least 3 factors:
1) Corn planted early is normally shorter than corn planted late due to a reaction to day length being shorter, early in the growing period.
2) Corn height was reduced due to suboptimal growing conditions during early development due to excess water and cooler temperatures in late April and parts of May.
3) Periods of excessive heat in early to mid June correlated with drier conditions and the corn plants often were unable to maximize growth as significant leaf rolling occurred and limited photosynthesis and moisture reduced cell elongation.
It may be interesting to look at the height as an indicator of potential yield, but chances are that it's minor compared to the water relations and temperature during pollination. For those farmers who missed the rains recently, we need to be concerned that the plants recover overnight and silk timely and, for now, be relatively unconcerned about plant height.
Black Cutworms, Fall Armyworms and European Corn Borer (ECB) have created problems this year, especially in fields planted with cover crops. The mild winter probably led to more insects surviving over winter. Continue to scout your fields with greater concern paid to weedy areas or late planted corn. Adding an insecticide to a spray program may be cost effective, especially in continuous corn. Ideally, pesticides should be applied when there is no wind and when bees are not visiting plants in the area. In general, evening or early night applications are the least harmful to bees. It also is worth doing some root digs to determine root damage from Corn Rootworm (CRW). Miller Hybrids has some adult corn rootworm traps to allow you to see the corn rootworm pressure you may have in rotated fields. Contact Miller Hybrids if you would like to participate in this monitoring program.
Identification photos created by multiple state extension agencies.
Nitrogen availability near flowering time and during grain fill is one of the most important differences in final yields.
Leaching and wash off of surface applied N, on wetter or compacted soils and in continuous corn situations have led to some later planted fields showing yellowing and stunting. Side dressing of small amounts of N could lead to yield increases, but it may take a while to get the active roots to reach the N.
Foliar feeding may be helpful to get the plants actively growing, so they can reach the available N. This is due partially to the fact that some surface Nitrogen was lost and partially due to the fact that roots stayed shallow due to a lack of oxygen during the cold period and now may be suffering from lack of moisture in the surface root zone.
Early planted corn has a deeper root system and more completely explored the N in the deeper soil profile.
Since Nitrogen is so important to your corn crop, the use of the Corn Nitrogen Rate Calculator Web tool will help guide you toward maximum profitability as the price of corn and the price of Nitrogen vary, but it only works if the Nitrogen is not lost before the plant gets to it.
Anytime you lay out cash for a hope of future return risk is involved. Manage that risk well by using a tool like the ISU extension Ag Decision Maker:
This is a great tool to use with your own costs and to help you put together a marketing plan for the crops or animals you manage, so you remain a profitable and sustainable farming operation. There are many input costs which you can control and the use of these tools emphasizes the need for a good marketing plan that is proactive rather than reactive. The people who had a marketing plan and sold or protected the price in June of 2016 were well rewarded last year, so preparing a marketing plan which will allow you to react to weather concerns this Summer may be a good move to be profitable in 2017.This is a critical year to have a plan that covers your variable production costs, since there is a lot of downside risk, especially for soybeans.