Last week much of the crop seemed to take a turn for the better. We had some good growing conditions with moisture that allowed the crop to get to some nutrients and put on some height. The fast growth can be a cause for concern, though.
There are some things happening in the field that we need to watch. Here are four factors to watch for this week:
1. Residual herbicides may be running out.
We have started to see some residual herbicides run out in corn. This is normal and expected due to the amount of rainfall and slow growth to canopy. Some have looked at a rescue treatment in corn to help control these late flushes. The corn has grown quickly, and since we are wet, many cornfields are too tall for a rescue treatment. Even for glyphosate-tolerant corn, the label only allows up to 48-inch-tall corn with drops. If you are planning to make a postemergence application of any herbicide, be sure to check the label and apply at the proper growth stage.
2. Corn leaf diseases are starting to appear.
This is mostly likely a topic we can talk about every week for the rest of the season. I am starting to see both gray leaf spot and northern corn leaf blight. Remember, gray leaf spot likes it hot and humid, and northern corn leaf blight likes weather a little cooler. Check with your seed supplier to determine what hybrids you have that may be susceptible to disease and scout them first. Also, you need to keep a close eye on corn-after-corn acres.
The other disease I have found a few spores of is common rust. We had a late outbreak in southern Indiana last year. In some cases, we had to spray. Rust is one disease we need to keep an eye on because it blows in with storms and can affect everyone. Some hybrids have better tolerance to rust than others.
3. Corn going down from wind could be an issue.
Some parts of the state received a lot of rain and wind this week. Amazingly, most of the corn has stood back up. If the plant did not break off due to green snap, or the roots did not come completely out of the ground, it should gooseneck its way back up. The key is to get it standing upright enough that it can pollinate.
4. Soybean weeds may still need attention.
The rains are great, but they have delayed some post applications of herbicides in soybeans. You need to pay close attention to what weeds you have and how tall they are to apply the correct rate and product. If you’re tank-mixing residual products in your post applications, be sure to check the plant-back restrictions, as some products can’t be used now because of carryover to corn. If you’re growing cover crops this fall, also look for plant-back restrictions for those crops.
Gauck is a team sales agronomist for Beck's. He writes from Decatur County.