Ants: Apparently more than just small children are repelled by vegetables. Ants are said to hate… cucumber of all things! Leave some cucumber slices or peelings around the point of entry; bitter cucumber works best.

Ants are said to never cross a chalk line. Other lines they reportedly will avoid:
Cayenne pepper (smart ants!)
Lemon Juice
Cinnamon
Coffee Grounds
Flour

Fleas: Chop up a lemon and score the skin. Add lemon to several cups boiling water, and let sit overnight. Then use it to sponge down your dog to kill fleas on contact.

Already have fleas in the house? Trap them! Take a shallow baking pan and fill it with a few inches of water. Add a little squirt of soap. Position a lamp directly over the pan to attract the fleas. The light will attract them in, and the soap will prevent them from jumping back out. (This also works for moths.)

Mosquitos: We all know that the best way to keep mosquitos off our property is to remove all standing water. But what to do if there is standing water that is too difficult to remove? Add 1 tsp of dish soap per gallon of standing water to destroy the larvae.

Another easy way to repel mosquitos (and pretty up the yard!) is to plant marigolds. The little bloodsuckers can’t stand the smell.

Got vaporub? Mosquitos are naturally repelled by the eucalyptus scent.

DIY Bug Spray: Add 2 1/2 teaspoons of any combination of the following essential oils to 1 cup of vodka:
Citronella
Juniper
Lemon
Myrrh
Palmarosa
Pine
Rose Geranium
Rosemary

Basically, try to smell like a tree!