I have received a few phone calls this week about yellow blemishes showing up on corn leaves. This looks similar to HPPD inhibitor damage (such a Callisto). However, it is caused by dirt that had clung to the plant earlier in its life.
The blocking of sunlight causes the plant to focus chlorophyll production elsewhere so it can be more productive. As the plant grows and the dirt falls off, the chlorophyll production should start back up.
There should be very minimal (if any) loss in production due to this syndrome.
