We love fruit in Northern Michigan. We're awfully proud we're one of the fruit-growing capitals of the world and we love that from spring through fall we can buy fresh fruit at local farm markets, grocery stores and farm stands. The one downside to all this fruit-loving goodness? Fruit flies.
By mid- to late-August our local fruit harvest is reaching its peak. Farm markets are brimming with blueberries, peaches and apples and the cherries that fell to the ground during the summer's harvest are often still there. Add to that produce of all kinds coming out of home gardens and a propensity of summer's damp towels, damp shoes and damp dishtowels and you have optimal conditions for the rapid expansion of the fruit fly or Drosophila melanogaster.
It's the rare Northern Michigan resident who hasn't experienced these annoying gnat-like flies that swarm anything sweet or fruity, anything with a hint of vinegar and anything damp. Many a porch picnic has been overcome with swarms of these flies, but even worse, people often have to bat them away at interior dinner tables.
How do they get in our houses and what in the world can we do about it?
First of all, fruit flies are very tiny, approximately 1/8 of an inch long), meaning they can often come in the house through windows and doors as they are opened or through any small tear in screens. They also hitch a ride in on produce, either from your own home garden or from the farmstand. Once their eggs and larvae are in your house, the battle has been waged and their ability to reproduce rapidly makes it often feel an impossible battle to win. Each female can lay about 500 eggs which turn into adult flies in around a week.
The most important steps to take are to put all fruit into the refrigerator immediately when you bring it into the house. Don't like brown bananas? Keep your bananas outside in a distant corner of your garage. Try to keep crumbs wiped clean, store your trash in a covered bin and don't put any discarded food in a trash can in your kitchen. They love the smells coming from your sink, drain and garbage disposal so once a day, boil water in your tea kettle and pour the water down your kitchen drains.
Do away with fresh flowers. This is very hard to do since fruit flies often coincide with late summer gorgeous blooms. But fruit flies love to prey upon the nectar and the standing water.
Beyond their attraction to food and flowers, fruit flies love anything damp. Be sure to launder your dish rags and dish towels with great regularity, rince them very well after using and squeeze as much water as possible out of them after each use. Never leave wet mops out and about or buckets that have any water left in the bottom.
Once you've got a fruit fly population, most people try to trap them in bowls and plastic bags using anything from soapy water with a little vinegar, a glass of wine, a piece of fruit doused in vinegar, rum and orange juice and some people swear by adding a little yeast. The idea is to create your concoction, pour it in a bowl and cover the bowl with plastic wrap. Poke some holes in the wrap. The flies swarm the fruit or liquid in the bowl, enter through the holes, can't find their way back out and eventually drown. The same principle holds true for a plastic bag.
Then there is the "cook them in the oven" approach. Caution: This is only a technique to be used with electric ovens. Put some fruit in the oven (fruit flies love bananas) at night before you go to bed, leaving the oven door open. The next morning, close the oven door, turn the heat to 400 degrees and leave the oven on for 10 or 15 minutes. People swear that the fruit flies are eliminated using this method, but be sure you then spend time cleaning your oven.
Sometimes the fruit flies can become so thick that you can literally suck them up in droves with a vacuum. And if you get down to just a handful, some people drown them one by one in a continuous stream of window cleaner or kitchen cleaner.
The most important thing to remember is to start early, at or even before the point that you see the first fruit fly of the season in your home. Prevention early on really makes a difference.