A winter wheat field near Owen Sound has 4 to 5 acres of “missing plants”, cut off at the soil level. Not many insects could do that kind of damage this time of year. It sounds like a case of winter cutworm. It was to the day, 4 years ago when I wrote a CropPest article about this pest. A very common insect that occasionally decides to munch on our crops. And this case can not be the only field in the area with feeding damage. I suspect there are more wheat and hay fields in the same situation. The problem with this pest is that it is very cold tolerant, surviving sub-freezing temperatures and can feed now on these sunny fall days and even under snow during the winter months.
As mentioned in the past article, I recommend that hay and winter wheat fields are accessed at least once before there is substantial snow cover. Look for bare patches in fields and larvae that may be present or moving in from neighbouring fields and ditches.
Not much can be done now to control the larvae. It is too cold to apply foliar insecticides but at least you will be aware of the situation and come spring, be able to assess any further damage they may have done over the winter.
Interestingly, this is one of the moths (Large yellow underwing moth) that tends to get caught in our western bean cutworm traps. Perhaps it is time for us to be keeping track of their numbers too and alerting growers to the potential risk of fall/winter damage.