Cover crops are gaining popularity with farmers across the United States. These off-season plantings can improve soils, reduce erosion, and keep nutrients in place. They may also provide a good habitat for overwintering and migrating insect populations. University of Illinois Extension Entomologist Nick Seiter is exploring if this is the case, and what impact it could have on the following field crop. He offers this example.
“What we’ve seen so far is that the risk of insect damage to soybean following cereal rye is relatively minor. Which maybe isn’t all that surprising, when you consider that soybean and rye are not that closely related. Where there is more of a potential impact from insect damage is when corn follows cereal rye. Where you have a grass following a grass. Or, for instance, if you had soybean following a legume like a clover. We don’t have a lot of that particular practice going on in Illinois but that is where you would expect to have an issue.”
Seiter and his student researchers are doing insect surveys across the state to quantify the field level population differences between cover crop rotations and conventional rotations. He says they are also checking to see if the termination timing of the cover crop makes a difference later in the growing season.
“What we probably want to try to avoid is a situation where the cover crop is dying right as the soybean or corn plants are in their most vulnerable stage, the seedling stage. So, we are looking at the effect of termination timing both in corn and starting over the next couple of years, in soybean to develop some management recommendations.”
Seiter says the goal is to keep the insect populations present in a cover crop from adversely impacting the following cash crop.
“What we are really trying to do with this is to make sure we get our management recommendations right so that we don’t cause a problem by trying to solve other problems with erosion, with nutrient reduction runoff, with some of these great benefits we can get from cover crops.”
The kind of great cover crop benefits that the research at the University of Illinois is helping farmers to deploy.