Many herbs have been used for insect control. Companion planting is used to help keep unwanted pests from fruits and vegetables. Others are planted to repel insects and rodents from coming into our houses. And still others are used to repel insects from biting our pets and us. Below is a small list of plants and how some people use them.

Agastache cana- Also known as mosquito plant for its ability to deter mosquitoes.
Basil-Deters flies and mosquitoes. Planted near Tomatoes is suppose to improve flavor and growth.
Borage-Deters Tomato worms. Also good companion for squash and strawberries.
Catnip- Most of us think of Catnip as a treat for our cats. Recently, researchers have reported that an ingredient in Catnip essential oil repels mosquitoes. It is said to be ten times more effective than DEET. It is also said to repel flea beetles and ants.
Citronella Geranium- Contains Citronella, which is used in many insect repelling candles, oils and sprays.
Garlic- Repels aphids and Japanese beetles. Good companion plant for roses.
Gopher Purge- It is said to deter gophers and moles.
Lemon Grass- Contains Citronella, which is used in many insect repelling candles, oils and sprays.
Lemon Thyme- Contains Citronella, which is used in many insect repelling candles, oils and sprays.
Lemon Balm- Contains Citronella, which is used in many insect repelling candles, oils and sprays.
Pennyroyal- Deters fleas, mosquitoes and flies.
Rosemary- Deters cabbage moths, bean beetles, and carrot flies.
Rue- Deters Japanese beetle. Good companion for roses and Raspberries.
Tansy- Deters ants, Japanese beetles, striped cucumber beetles, squash bugs and flies.