I was so frustrated from swatting at gnats every day in my house. I had them go up my nose, in my mouth and eyes, and actually bite me so hard once that I yelled. We didn't keep much, if any, food out on the counter, so the gnats even resorted to getting in our diaper pail! Talk about disgusting - poop-fed gnats going in your eyes and biting you. It doesn't get much worse than that. Even my two year old son started mimicking my swatting and trying to catch them out of the air with a loud clap. I tried several iterations of this trap, and finally hit the jackpot with the one in this instructable.
You'll have some fun when you notice gnats on the fruit. Give the plastic a flip and the gnat will fly into the corner between the bowl and the plastic. If you get good enough, you can smash them without putting a finger hole in the plastic!
Step 1: Gather Your Gear
- A serving bowl or large salad bowl. I chose a 9 inch salad bowl, about 2 1/2 inches deep.
- A small fruit cup, shorter in height than the large bowl. This is very important.
- Fresh fruit, approximately 1/4 cup. I have used banana with great success, but used grapes for this instruction
- 2 cups of water
- Liquid dish soap
- Cellophane wrap (I used Saran Wrap)
- Serrated knife
- Food coloring (optional)
Step 2: Put Water in the Large Bowl
In the large bowl, put approximately 2 cups of water, such that there is at least 1 inch of water in the bowl. You can add a drop or two of food coloring now if you desire.
Step 3: Add Fruit to the Small Bowl
Cut up some fresh fruit for your enemy to dine on. Bananas are best but I'm out, so I'm giving grapes a try. DO NOT add water to the small bowl; this will cause the fruit to rot much too quickly.
Step 4: Place the Small Bowl Into the Large Bowl
Step 5: Add Some Soap
Put two or three drops of liquid dish soap in the water. This breaks the surface tension of the water, allowing the gnats to sink to the bottom instead of float for hours.
Step 6: Cover the Bowls With Cellophane
It's important here to make sure the plastic wrap is perfectly sealed around the edge of the large bowl, or the gnats will just come in, get a snack, lay some eggs, and fly out of your trap.
Step 7: Poke Some Holes in the Plastic
With the tip of the serrated knife, poke some holes about as large as a pencil lead (old school, not today's mechanical leads). This will allow the gnat to enter the trap, but the plastic will have a sort of tunnel effect, capitalizing on the gnat's poor flying accuracy and keeping him in the trap. I poke holes about 1 1/2 to 2 inches apart, and be sure not to poke any above the edge of the smaller bowl or they might get lucky and fly directly up and out. Poke 5 or six right above the fruit cup.
Step 8: Set the Bowl in a Gnat-frequented Area
The kitchen counter near the fruit bowl works best. There is no alternative to gnat control like putting the fruit away and taking out the garbage every night. We still had a problem, but this killed around 40 gnats in two or three days. I recommend changing the fruit every three days or you'll have a hairy beast to clean up.
Step 9: Count the Dead
In less than 5 days, there are 49 dead gnats in my trap. There were no hatches on the fruit, but I think it was important to let the fresh fruit get a little ripe so the smell attracted them. Even now there are gnats we see around that we know will find their way to the kitchen counter and into the trap.