My area has a real range of conditions with corn planting 65-75% complete in the northwest part of my area. There is maybe 15% of the soybean crop planted in the northwest part of my area. The corn and soybean planting progress is 95%+ complete in the northeast part of my area.
Questions today are replant decisions and effects of the frost damage to corn.
Corn replant decisions are based on the yield potential of your current stand versus the potential yield of the replant crop. A stand of 20,000 plants per acre today from a late April planting date will yield about 89% of normal. A replant date of May 20 will produce a corn crop that yields about 87% of normal. Therefore, you should keep this stand and not replant it.
If only it was that easy. The areas of fields that need replanted defy logic for the most part. Sure there are drowned out areas that will be easy to replant - when it dries out. However, many areas that will need replanted are kind of hit and miss.
Ideally, we would like to see those areas worked up so you eliminate the original stand and therefore eliminate the competition from the original stand. However, many of these areas are not real conducive to reworking; since they are irregular in size and difficult to get to without running over some good crop.
So, no, there are no easy answers. The good news is that replanting corn in May is usually low risk. Also, hybrid maturity does not have to be changed very much. Something in the 100-day hybrid maturity will work well.
The frost was an unwelcome addition to the crop challenges this spring. Initially, the damage does not look too severe. However, many times it takes awhile for the damage to show up. Therefore, the advice is to be patient when evaluating damage from frost.