A few fruits can be used as effective insect repellent, as can fruit-bearing trees and herbs. Citrus fruit such as lemons or limes offer some of the best natural repelling qualities.
The compound limonene found in the citrus deters insects such as flies, mosquitoes and fleas. To make and effective repellent spray from a lemon, quarter the lemon, cover it with boiling water and let it sit overnight. In the morning, strain the quarters and decant the water into a spray bottle.
Neem Fruit Oil
Neem trees have insect repellent qualities in its fruit, seeds, leaves and bark. The oil pressed from the skin of the fruit and seeds is effective against fleas. Other parts of the tree can produce a broad insect repellent and pesticide. The limonoids in the plant interrupt the feeding and breeding pattern of the insects and eventually kills them.
Other Insect Repelling Plants
Herbs such as citronella, lavender and pennyroyal, and eucalyptus, cedar and Kentucky coffee trees all have insect repelling qualities. Some naturally repel insects, but others need to be reduced to an essential oil form to act as a repellent.