Welcome!
June 22, 2020
TWISTED CORN AND YELLOW "FLAG LEAVES"
Many of the recent calls and field
visits have related to corn that is twisted up, and often "floppy"
and/or many corn plants displaying a yellow upper leaf. There are three
potential causes for this. Mark Licht discusses them at https://crops.extension.iastate.edu/blog/mark-licht/twisted-whorls-buggy-whipping-yellow-leaves.
Mark's emphasis is on a phenomenon commonly called "rapid growth
syndrome," although it is known by other names, which Mark mentions.
In the last sentence of the first
paragraph, Mark states, "Growth regulator and acetamide
herbicides can also be the culprit."
Growth regulator herbicides
include:
Acetamide herbicides include
I have been in several fields with
twisted corn where Resicore was applied. The active
ingredients in Resicore are:
The answer is, "Who
knows?"
The good news is that the vast,
vast, vast majority of the plants will "break out" of the twisting
without consequences, regardless of the cause. The yellow top leaf is one that
just "broke out" and has not yet had much chance to conduct
photosynthesis. An inspection of lower leaves on the plants will reveal that
they are wrinkled, especially along the leaf margins, from the prior twisting.
If a stake is placed by such a plant and then the plant is re-visited in a few
days, the leaves will all be green.
REMINDER
Remember that the on-line field
day for the Southeast Research and Demonstration Farm begins Tuesday at 8:00
a.m. Although there is no fee, registration is required and you will then be
sent the link to join. You may participate in part or all field day webinars.
Certified Crop Advisor CEUs will be available for the last three sessions. To
see more information, see the Calendar Items following.
CALENDAR ITEMS
Spring Field Day - Southeast
Research and Demonstration Farm
8:00 - 8:30 a.m., Tuesday through Friday, June 23 - 26, 2020 (a
different topic each day)
On-line
Details, including
required registration, are at: https://www.extension.iastate.edu/Pages/eccrops/meetserc.html.
Spring Training for Certified Crop
Advisors
8:00 a.m., Wednesday, July 1, 2020
On-line
Details,
including required registration and $25.00 fee payment, are at: https://www.extension.iastate.edu/Pages/eccrops/meetserc.html.
If you have any questions, please feel free to contact the Iowa State University Extension Office.