Be on the lookout for mites all the time but especially during seasons and years that are overly dry and hot. This is when mites are most likely to strike.
Turn over the leaves of your corn plants to look for mite damage. The underside of leaves is where you'll see mite damage first. A leaf with mite damage will look like it's been burned.
Examine your corn plants carefully. Even the smallest hint of mite damage requires your immediate attention because it will only get worse if the mites are allowed to continue feeding and breeding.
Look for dead leaves. If you missed the early signs of mite damage -- the burn marks -- then the leaf will likely die. Once you start noticing dead leaves, you must take action right away against the mite infestation.