Fruit Flies

Welcome to what I hope is the least appetizing post that will ever appear on my blog. While I typically try to discuss appetizing things, today I will talk about something less pleasant, fruit flies. The season is coming up here in the Midwest.  I personally have had some epic battles with these pests over the years.  The best way to stop fruit flies is to prevent them before they get a foothold. So in anticipation of fruit fly season, this post is designed to help you get a battle plan in place before they arrive.

Whether you call them fruit flies, bar flies, drain flies, or any of the other names they have, your guests find them an unappetizing annoyance. The guests rarely take into account the fact that they are studied for tremendous breakthroughs in science and were responsible for the 1995 Nobel Prize. They also fail to realize that the fresh salad and beer they are enjoying for lunch are the reason they are there in the first place. Instead, they want them gone. So after a little research and several personal experiments with different methods of fighting them, I want to share my best practices.

First, an understanding of fruit flies is in order. Fruit flies are laid as eggs. When they hatch they become larvae and depending on the temperature will become flies in 5-7 days. This means that the source of your flies went unresolved for almost a week before you became aware of them. They require two things to thrive: food and moisture. They feed and lay their eggs on ripened and over-ripened fruits and vegetables. They can also thrive on residue in drains and beer taps. They don’t require much food meaning that trashcans, recycling bins, empty bottles, and used towels can be breeding grounds as well.

Once they have started flying around, they key is to remove any breeding grounds they might have.  One female fruit fly can produce as many as 400 eggs. This means that once they begin breeding, their numbers will grow far more than exponentially. Deep cleaning and drying all surfaces and floors fully is the first step. Used linens should be kept away from dining and food commercial storage areas overnight. All beer taps should be covered. Placing tape over most of the surface opening overnight should test drains. If flies are found on the tape in the morning, a deep foaming cleanser should be used to clean the drain pipes. Overly ripened produce should be discarded nightly. Keeping the front and back of the house clean and dry will prevent the fruit flies from having a safe habitat for their eggs.

When you have the breeding grounds eliminated, you can address the flies that are already in the restaurant. The good news here is that they have a very short lifespan and need to feed constantly. The first step is to eliminate as many feeding opportunities as possible. Cover beer taps and liquor bottles behind the bar. Remove as much debris and moisture as possible from side stations and kitchen areas. The second step is to set a trap by offering them a treat.

I have read and tried numerous methods and ingredients for building traps. The one that I find most effective by far is whiskey. Any dark liquor will do, but whiskeys seem to have the best success rate. Place the whiskey or bourbon in a short glass (rocks or lowball) and cover it with plastic wrap. The amount depends on the diameter of the glass, but in general only a half-ounce or so is needed. Poke one hole in the center of the plastic. The flies will get in the glass to feed on the whiskey, but will become disoriented and not be able to fly out. By morning you will find many flies floating in the glass. The traps begin to lose effectiveness after a few days. I recommend setting multiple traps and changing their location. The bigger the problem, the more traps you will want to use.

In an ideal world, fruit flies would not be an issue. Unfortunately, they are part of the tradeoff for using fresh produce and serving beer. Creating a routine that prevents them from being able to breed will prevent them from becoming a problem. It is not uncommon for even the cleanest of restaurants to have some. When they get out of hand, it is time to address the causes. Attack them where they breed and you can prevent the problem from getting much worse.