Nebraska Extension Blog by Jenny Brhel
Determining Corn Growth Stage: Grateful for the rain showers! With the cooler weather, corn plants appear shorter due to shortened internodes but are further along in development than one may think. Correct growth staging of corn using the collar method is important. Some herbicides have application restrictions of V8 (8 leaves), particularly when certain adjuvants are used. These restrictions are in place to protect developing corn ears.
Be sure to growth stage plants correctly counting collars (leaves pull away from the main stem like a collar around one’s neck). Start counting leaves at the base of the plant with the smallest rounded-tip leaf with a collar as #1. From there count every leaf with a true collar. Leaves that are still wrapped in the whorl around the main stem without exposed leaf collars are not counted. Plants around V6 (6 leaves) start losing the lowest leaf.
The growing point emerges above ground between V5-V6. After that point, splitting the stalk becomes the most accurate way to determine plant growth stage when lower leaves are absent. To stage using this technique, dig a plant inside the field (past the endrows) without breaking the stalk. Carefully split the stalk down the middle through the root ball. At the base of the stalk is an inverted triangle that contains Nodes 1-4 (but they can’t be differentiated). Next look for the white area above that (about ½-3/4”) followed by the next visible band. The white area is the internode with the band being the 5th node (V5). There’s about an inch of internode between V5 and V6. After that, internode length is more dependent upon air temperature instead of soil temperature. Every leaf is attached to a node. Pull off the fully collared leaves and follow them back to where they break off at a specific node. Count the nodes on the stalk to the highest collared leaf that breaks off at a node to determine the growth stage. Once you determine the correct growth stage, you can consider painting a known leaf stage on certain plants (ex. paint the 6th leaf) and then count successive leaves from there when the field is checked. This avoids you having to split more stalks in the future.
Crop Share Survey: The economics team is asking landowners and tenants for input into a Crop Share Survey to better understand lease structure, shared expenses, and educational needs for those utilizing crop share leases in Nebraska: https://go.unl.edu/2025cropshare.
Toxic Plants Webinar Series regarding how the plants impact livestock health will be held June 11, 18, and 25 from 7:30-8:30 p.m. each evening. More info. and register at: go.unl.edu/toxicplants
June 17-18 Tractor Safety Training in York: This is an opportunity for youth to learn how to safely operate farm machinery and receive a farm husbandry certification if they’re 14-15 years old. For more information and to register, please visit: go.unmc.edu/tractor-safety-training
June 17th Prairie Strips Tour: Pheasants Forever is hosting a field day at Logan View School near Hooper in conjunction with UNL Extension from 9:30 AM to 2:30 PM, focused on prairie strips and their role in agricultural productivity and natural resource outcomes. RSVP at: nebraskapf.com/habitat-tours.
June 25 Weed Management Field Day will be held from 9 a.m.-1 p.m. (Reg. 8:30 a.m.) including lunch at UNL’s South Central Ag Lab near Clay Center. The event is free but pre-registration is needed for lunch count at: https://go.unl.edu/qemk. The event will demonstrate weed control options in soybean, corn, and sorghum. Management options that will be demonstrated include: various herbicide programs including ones with overlapping residual, timing of hairy vetch termination for weed control in sorghum, planting date and metribuzin based herbicide program in soybean, termination timing of cereal rye after corn planting, volunteer corn management in Enlist corn, and evaluating Surtain for weed control and crop safety in corn and popcorn.
