Insurance adjustors for hail companies have learned the routine. Once a farmer sees a field that has been hit by hail within the hour, or even the next day, he's nervous and excited. And if he has hail coverage, he's going to make a call. Why not? That's why you carry the coverage. However, adjustors have discovered that they have two options- go out and see the farmer right away and help reassure him it may be better than he thinks, or wait a week to 10 days to go visit. In almost every case, except the most extreme, crops hit by hail look better a week later than the day they were hit, especially if they were small.
This scenario has played out many times already this season. One farmer says he looked at his ankle-high corn the day it was hit, the next day, and the day after. It looked worse every day as the tissue that was damaged turned brown. But since the growing point was still below the ground, it wasn't at risk. When the inspector finally made a determination about 10 days later, he concluded there was no damage on the corn, and the farmer agreed. It grew through the vegetative damage at the young stage.
According to the Purdue University Corn & Soybean Field Guide, 2011 edition, published by Purdue's Diagnostic Training Center, you can make your own observations and arrive at a conclusion by waiting at least a week, then picking 1/1000th of an acre spots at random and doing stand counts. The trick is how many plants will likely survive and produce an ear. If the corn was young and the damage was to leaves, not stalks, as in the case above, most if not all stalks could still have a chance of producing an ear. That's what helps reduce the actual amount of economic damage to either zero or a low figure if the damage is early and not extremely severe.
If you're in 30-inch rows, you'll want to count the number of stalks remaining in 17 feet and five inches. So it several times in different locations, picked at random. The actual Field Guide instructions say do it once, then in two other rows, then at three other locations.
There is a worksheet that can guide you through this estimation of yield remaining or yield loss if you still get hit with hail from this point forward. It's called AY-264-W, by Bob Nielsen, corn specialist. You can find it at: www.agry.purdue.edu/ext/pubs/AY-264-W.pdf).