Finally corn and soybean fields are planted and are up and growing. Now growers need to walk their fields often or hire a professional to identify crop issues that can impact yields.
What happens in the next 80 to 90 days will have a major effect on maximizing yield potential. A good tool for scouting plan is the Corn and Soybean pocket Field Guide from Purdue or Ohio State University. Here are some potential problems to monitor.
There are corn fields where seedling blights — especially Pythium — had an effect on the stand, especially in early planted fields. With the wet and cold conditions of early May, soil borne insects including wireworms and seed corn maggots attacked the seed and also hurt the stand. For some fields where 30,000 to 34,000 kernels were dropped, because of seedling blights and insect issues, stands were reduced down to 24,000 to 28,000 plants.
With many corn fields planted with the Roundup Ready trait we have become lax in keeping track of weed issues. This year with pre-emerge herbicides applied early and no rain following, weeds have come back and need to be controlled so as to not compete with the growing crop.
Take note especially in corn fields for the plants’ response to a lack of nitrogen. After last year’s heavy rains following planting and losing the majority of the field’s nitrogen, many growers in 2016 are having a nitrogen stabilizer added to their nitrogen applications. To maintain the higher corn yields, we need to have the required N amounts into the plant prior to tasseling. If in doubt, use a Pre Sidedress Nitrate Test (PSNT) to determine how much nitrogen is in the ground.
Another area to keep track of is the presence of insects in fields in the next several weeks. Armyworm and stalk borer can still attack the later planted corn fields up to July. In fields of continuous corn as well of areas where corn rootworm hatches have occurred, we need to watch for feeding. At times of higher than normal pressure by this insect, we can see more early root feeding that could result in stalk quality and standability issues later in the growing season, which can reduce yield if not harvested early. Depending upon the area, this insect has been found in first-year corn fields following soybeans.
In the darker soils of the soybean fields, I have seen bean leaf beetles take out existing plants to the point the growers had to replant in these areas. Under dry growing conditions later on, these pests could cause significant leaf damage and may warrant an insecticide application.
As we walk our fields, pay attention to any leaf diseases that have been present in past years. Normally gray leaf spot and northern corn leaf blight will occur, if the conditions are right, prior to tassel and shortly after tassel. Both of these diseases start at lower areas of the plant and will move up. With the lower grain prices and the high cost of fungicide applications in corn fields, check a current seed guide for the hybrid’s tolerance to both of these foliar diseases. Most hybrids today have very good tolerance to these diseases without yield reduction. An offensive type hybrid without good tolerance to these diseases may need a fungicide application.
It is important to note seedling blights or root rots that impacted early soybean stand establishment. When walking soybean fields take a hoop or measuring tape to see what your population is when determining yield potential. In areas where sudden death syndrome or brown stem rot is present, a fungicide application will not help.
Taking the time to walk and scout crop fields will help growers stay on top of issues affecting crop growth and yield potential. Due to lower crop prices we need to make sure we are getting the most bushels per acre come fall and to really know what is happening out in our fields, we need to take the time to take a walk.