Remove any fruit or vegetables that are infested with fruit flies, and dispose of them outside.
Fill a spray bottle with 3/4 cup (6 oz.) of warm water. Add 30 drops of lemongrass essential oil to the water, and close the bottle. Shake the bottle well.
Spray all surfaces of any rooms that are infested with fruit flies. Spray sink drains, fruit and vegetable storage areas, and areas near house plants. Wash away any dead insects with a wet soapy cloth, or a sink sprayer.
Repeat at any time when you notice fruit flies. Prevent future infestations by storing fruits and vegetables in a refrigerator, or by using them immediately bringing them into the home.