Recently, I’ve received calls from concerned farmers on a wide range of topics from volunteer corn to weed resistance and corn rootworms. There is no simple solution to these problems, but rotation is one common management practice that can certainly help.
Consider how rotation can help with these issues:
- Herbicide-Resistant Weeds. Resistance to glyphosate-based herbicides (e.g. Roundup®) is due to using herbicides as the only source of weed management. Weed resistance can be significantly slowed down or even averted altogether with careful crop and herbicide use plans. Bring LibertyLink® or conventional soybeans into your rotation. Likewise, when it comes time to plant corn, use conventional or straight LibertyLink hybrids. Using herbicides that have different modes of action is critical.
- Volunteer Corn. With careful crop planning and herbicide usage, volunteer corn can be controlled in both corn and soybeans. Several herbicides (e.g. Select, Fusion, Poast Plus, etc.) will take care of volunteer corn in soybean fields, but persistence is key as more than one application may be needed.Volunteer corn in continuous corn situations can be managed by understanding the herbicide tolerances of the traits involved. For example, most Monsanto-traited hybrids contain only the glyphosate-resistant trait for herbicide use. If you plant corn following one of those hybrids, choose a hybrid that incorporates the LibertyLink trait. If you plan to have many years of continuous corn, stay away from hybrids that contain both the LibertyLink and the glyphosate gene for herbicide resistance. Rotating to soybeans or alfalfa also can help break that cycle.
- Corn Rootworm. Continued use of the same rootworm resistant (Bt) trait in corn hybrids, coupled with the lack of required refuge acres, has caused rootworm resistance to become an issue. Rotation is key. Rotate traits between Monsanto, Agrisure and Dow products. They may also need to rotate to other crops (like soybean or alfalfa) if rootworms cannot be managed by rotating traits. Additionally, the use of hybrids with more than one rootworm trait (e.g. SmartStax) may need to be used. Refuge acres must be planted, and Refuge-In-the-Bag (RIB) hybrids make compliance simple. Respect the refuge® and it will greatly increase our likelihood of keeping rootworm traits viable for years to come.
* Respect the refuge is a registered trademark of the National Corn Growers Association