There might be literally millions of insects in a field, how many lasers would you need for that? Also, you would need much more precise sensors as detecting a

There might be literally millions of insects in a field, how many lasers would you need for that? Also, you would need much more precise sensors as detecting an insect is way harder than a bird. Such system would be way too expensive, unless you'd like to pay 100 euros for a loaf of bread.