REACHING GRAND GROWTH STAGE
This corn is at about the V7 growth stage, with the growing point above the ground. It is near the stage where it will seemingly grow overnight. Specialists actually found an explanation for why corn grows quickly once it nears waist-high. Purdue University’s Bob Nielsen says once corn reaches the 10-leaf stage, it requires considerably fewer growing degree days to produce the next leaf than before that stage.
Note the two leaves Dave Nanda is holding against a backdrop of healthy corn at about the V7 or seven-leaf stage. This field was hit with hail twice at about V4, with the growing point below the ground. Some leaves were tattered even during regrowth, such as the ones Nanda is holding. This field yielded around 240 bushels per acre in 2018, despite the early hail.
KEEP EYES PEELED
John Obermeyer, Purdue Extension entomologist
Large catches of armyworm moths a couple of weeks ago mean armyworm larvae could be at work in certain fields now, or very soon. They can cause lots of damage in a hurry, agronomists warn. Scout for signs of feeding and the worms themselves. Treatment may be needed. Note the armyworm larva on this young corn leaf.
Nanda split the stalk on this corn with eight leaves, or at the V8 stage, to show what’s inside. He’s pointing to the growing point, which is now well above ground. Hail at this stage would be much more damaging than hail was at V4. If the growing point is severely damaged, the plant won’t regrow at this stage.
At this stage, if only a plant here and there is showing symptoms like the small plant with leaves drying up, you feel fortunate, Nanda says. There are several possible causes here, and it’s not always possible to pinpoint the cause. In this case, the farmer suspected anhydrous burn on some plants, which could have damaged this plant’s roots. This plant may have been one where the whorl twisted and never recovered from an early hailstorm, although almost all plants did recover. Note such symptoms and examine the plants, but don’t panic, Nanda advises.
If you pull back corn at V6 or V7 and find these tall waterhemp plants, it’s not a good day. The farmer who found these weeds had no idea they were in the field. He was able to burn them down with herbicide and now knows to treat the field as if waterhemp is present.
Parts of this field, especially to the far left and right, appear to be very pale green as the operator makes the sidedress application. Speculation is that plants may have been borderline on nitrogen before liquid N was injected on this pass.