Q: I am at my wits' end. I have fruit flies in the cabin of my 2012 GMC Sierra 1500. I never ever eat fruit to begin with, and I never allow anyone else to eat it in my truck. I have fogged the interior with enough Raid to cause genetic mutations in my grandchildren, to no avail. The bugs return within a week. Short of using a flame thrower, I can't imagine what else to do.
Upon further consideration, the flame thrower gambit is out. I don't want to escalate the tensions. But any other advice would help me.
A: First of all, you should eat fruit. Fruit is part of a healthy diet, and we'd like you to outlive the fruit flies.
You've already eliminated any visible sources of food for them, and you've even resorted to chemical warfare. So what's going on?
Honestly, I don't know. I'm a mechanic, not an entomologist. But I'm guessing there's a source of food for them somewhere in your truck that you haven't found. Are you sure your kids aren't sneaking in a tidbit or two of fruit when they sit in the back where you can't see them? Or, it's possible someone dropped something onto the carpet and then it got mashed by a shoe. So a thorough upholstery and carpet cleaning is a good place to start.
My other guess is that there's some organic material that's dropping onto the hood of your car and entering the ventilation system through the cowl (the fresh air vents where your windshield meets the hood). If something from a fruit tree fell through the cowl, it could attract fruit flies there. And from there, the flies could make their way through the ventilation system to the cabin.
Look at what trees you're parking under. And once you're sure you're not continually replenishing their food supply from above, nuke the cowl area with the fan on full blast. If that doesn't work, you'll need to get into the HVAC system to clean it out. We hope it doesn't come to that because that stuff is tucked up under the dashboard, and not easy to get to.
If there's still an infestation after all that, you'll have to move to Alaska and sell the truck there next winter during the flies' dormant season.