- Emerged corn will put on a new leaf every 84 GDU [Growing Degree Unit] up to V10
- The remaining Vegetative Stages will put on a new leaf every 56 GDD
- What does this mean? For easy math, assume 20 GDU’s will accumulate per day in June and into the first part of July. A new leaf collar can be found in your field every 4 days! If you are really bored, you could watch the corn grow this time of year.
Other important stuff going on right now…
- The growing point and tassel rise above the soil surface at V6.
o What does this mean? If corn is damaged at the surface or defoliated, it is unlikely to regrow.
- The number of kernel rows is determined at V7-V8.
o What does this mean? Stress at this time is bad…some stresses are unavoidable, but some are manageable [such as top-dressing/side-dressing nutrients, foliar applied products, etc.]
- The greatest risk for brittle snap in corn is from the V5 – V8 leaf stage (and again from V12 – R1)
o What does this mean? Corn is going through the awkward stage of rapid growth…it’s the nature of the beast.
- Growth Regulator herbicides can increase the brittleness of corn, in turn increasing the risk of brittle snap injury [dicamba, clopyralid, 2,4-D]
o What does this mean? Some of these products are necessary to control our late-emerging broad leaves. The interaction is common and manageable with hybrid selection and placement…follow the herbicide label!