No food: Why are there are fruit flies all over this truck?

Dear Car Talk: I am at my wits’ end with this. I have fruit flies all over 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. They eventually return within a week.

Could it be that, due to the fruit flies’ ability to mutate, they have developed into a strain of “super f lies”?

Short of using a flame thrower, I can’t imagine what else to do here.

Upon further consideration, the flame thrower gambit is out. I don’t want to escalate the tensions. Any advice, no matter how bizarre or deviant, would help me. — David

Well, first of all, you should eat fruit, David. Fruits and vegetables are part of a healthy diet. And we’d like to see you outlive these fruit f lies.

Fruit f lies like rotting fruit; fruit that’s fermenting. And you’ve already tried the basic remedies.

You’ve eliminated any visible sources of food for them, and you’ve even resorted to the arena of 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.

While you don’t allow people to eat fruit in your truck, if you have kids, and they sit in the back where you can’t see them, all bets are off.

It’s possible someone dropped something onto the carpet and then mashed it in with a shoe to try to hide the evidence. 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).

Let’s say something from a fruit tree dropped onto your car and some part of it fell through the cowl. It’s possible that it could rot and attract fruit f lies there. And from there, the flies made their way through your ventilation system, and yelled, “Party!” in the cabin of your truck.

Maybe it doesn’t take actual fruit to satisfy them? Maybe tree sap is good enough if they can’t find a local watermelon stand that’s open?

That could explain why they keep coming back, even after you napalm the inside of the truck.

You may want to start looking at what trees you’re parking under. And once you’re sure you’re not continually replenishing their food supply from above, then the solution may involve nuking the cowl area with the fan on full blast.

If that doesn’t work, you may need to get into the HVAC system itself to clean it out. That stuff is all tucked up under the dashboard, and not easy to get to.

So we’ll hope that a thorough cleaning, more judicious parking, and maybe some highly targeted chemical application ends your infestation.