I've seen a few fruit flies this year but our biggest problem insect is earwigs. They are harmless but they get into everything. One year I pulled my transfer tubing out of the storage box and there were literally hundreds of them in the tubing.
We had never seen then in Iowa until 6 or 7 years ago. Now they are everywhere.
Fruit flies can be a problem but earwigs are just too creepy.
I named my last brew "Earwig APA" because there were about 20 of them in my mash tun (I think I rinsed most of them out). I'm brewing outside so my cooler was sitting on the deck and they love that crack around the top of it. Biggest problem here are "beer bugs" or sap beetles. Little black guys with white dots on their back. I pour 3 beers when my wife and I are drinking outside. One for her, one for me, one for them.