Yield Impact of Volunteer Corn
- Volunteer corn can reduce yield, like any other weed species, by competing with the crop for available resources such as light, nutrients, and water.
- Volunteer corn plants from dropped ears are more likely to emerge in clumps than as randomly dispersed plants.
- Plants in a clump must compete with each other in a limited space for the same light, water, and nutrients, making them less competitive with the crop than randomly dispersed plants.
Volunteer Corn Management Options
Selective use of fall tillage
- In southern corn producing areas where the growing season is longer, early fall tillage can stimulate germination and emergence of volunteer corn prior to the winter freeze, thus reducing the amount of potential emergence the following spring.
- If early fall tillage is not feasible or soil conditions are not conducive for seed germination, another strategy is to avoid fall tillage altogether. Incorporation of seeds into the soil provides a favorable protective environment for winter survival; whereas, seed left exposed on the surface are more susceptible to decay or predation.
- Fall tillage will likely be counterproductive if the soil is too dry for corn seeds to germinate and emerge before the winter freeze.
- Spring tillage can effectively manage germinated and emerged seedlings.
- However, if conditions prior to spring tillage are not conducive to germination and a large quantity of viable seed remains on the surface, tillage may effectively “plant” more volunteers than it controls.
- Vertical tillage implements intended primarily to manage residue with minimal soil disturbance are less effective at removing emerged volunteer plants and may make things worse by shattering ears and spreading seed.
- Rotating to a different crop expands herbicide options for controlling volunteer plants. Selective grass herbicides, such as Assure II, effectively control volunteer corn in soybean.
- The ACCase herbicides, such as Assure II, Fusilade, Fusion, Poast, and Poast Plus, can be used to control volunteer corn in soybean but have intervals ranging from 30 to 120 days after herbicide application before corn can be planted.
- Select Max has a plant/replant interval of only 6 days for corn and thus is the only ACCase herbicide that can be used for control of volunteer corn before planting.