 you spilled fertilizer on your lawn. It's just essentially burning the grass, that salt content on there. As far as control, during the growing season, if you happen to be outside, you see where your pet uses the bathroom, if you flush it, that can help. Again, obviously you have to be there and do that. The other option is if you can train your pets to go in one area of your lawn, essentially it's kind of a sacrifice area.