Nice work on the pictures
@G59 . I don't see the anthracnose we spoke of earlier nor any fungal disease. However, I do see plants with nutrient deficiencies.
When I look at photos 11 and 12 for example and others, I see plants that appear to be overcrowded and nutrient starved. In addition, I noted your comment "
lined the walls and bottom of the bed with fabric to stop the roots of nearby fruit trees from getting in"
While you may have stopped the roots of nearby fruit trees, you also appear to have stopped the roots of your corn.
When planting corn on a raised bed, the recommended spacing is two plants per square foot. The majority of the root mass in corn is found in the top 3 feet of soil, which is where most of the nutrients and water are absorbed. Corn plants have a fibrous root system that spreads out horizontally as well as vertically. The overcrowding affects the horizontal roots negatively and the fabric liner affects the vertical roots negatively creating a situation of nutrient deficiencies IMO.
At this point in the growth cycle, there isn't much of anything you can do. Next time, try to give more spacing for those horizontal roots and more depth for the vertical roots.