Their are many yard pest that can infest your yard. Two of the main yard pest right now are army worms and mole crickets.
Army worms will literally come in droves and march side by side through a yard giving them the name Army worms. They look like a greenish caterpillar. They will eat grass and really prefer Bermuda grass. If you see brown patches in your yard it can be army worm activity. They are very active at night and like to hide in tall grass, ground cover or under leaves.