Central Iowa received several storms during the past two weeks. There were three distinct situations occurring: rivers and streams out of the banks, ponding, and extremely saturated soils.

When there is standing water plants have roughly 48 hours before they’ll die. By now you will know if the corn or soybeans in your field survived. Saturated soils can act like standing water also. The water is just below the surface and it can suffocate plants. In all situations expect root diseases to increase, stalk rot to increase in corn, and root diseases to increase in soybeans.

As everyone knows, there was very heavy rain in Humboldt and Webster County – among other places. On Monday I drove through northern Humboldt County. The corn has been flattened, not just severely lodged. Of course this triggers questions about what to expect for the remainder of the year. Fortunately much of the corn has already dented so it should progress toward maturity and there should be corn to harvest IF the farmers can pick it up. There will be many fields that are harvested in one direction this year. Although Humboldt County seems to be the most severely damaged, it’s common to see lodged corn in nearly all parts of central and north central Iowa. I’ve seen downed corn in every one of the nine counties I travel. There are two things I expect to see increase due to the wet conditions: stalk rot and mycotoxins infection of the kernels. Wet soils are a haven for stalk rot so farmers should start doing the old pinch test to check for stalk rot in the next couple of weeks. Damaged corn often equates to corn with mycotoxins. As harvest approaches check ears for mold on the kernels and have the grain checked if you find any.

The wet weather hasn’t been a friend to the soybeans either. It was common to see soybeans standing in water or see areas of the field that had totally covered the beans. The water has now receded in many cases and it is easy to see the “holes” where the ponds were located. As I mentioned earlier, expect to see root rots increase.

During the past couple of days I’ve been in many soybean fields collecting samples for the ISU Soybean Disease Survey. Most of the soybeans are at the stage where all the pods are full and some of the beans are just beginning to turn yellow. The main diseases present are brown spot in the upper canopy and SDS. This year has been a banner year for SDS. It’s easy to see those yellow spots from the road. Now many of the plants in those spots are losing their leaves. Remember that SDS infects soybeans early in the year and is very closely tied to the level of SCN in fields. Palle Pedersen continues to remind farmers just how important it is to select a variety with strong SCN resistance. This is one of the reasons why. Yesterday I found my first plant infected with white mold in a field near Iowa Falls. (I only found the one plant.)

Clearly the weather has been the big news during the past two weeks. Hopefully the rain will stop now and we can look forward to a dry harvest season.

SOURCE: ISU’s John Holmes