One of the most accepted wisdoms of companion planting is the use of repellant plants to keep bothersome insects away from their favorite vegetable plants. Insects locate their favorite plants through smell and many repellant plants work by masking the scent of their neighbor plants. That is why strong-smelling plants such as basil, onions, garlic, and marigolds are good reliant plants (It is a good practice to crush a few leaves or flowers on your repellant plants each morning to help release their scent.)
The following is a brief list of some excellent repellant plants as well as some cautions on their use.
BASIL - Repels flies, potato bugs, and mosquitoes, but should not be planted alongside rue.
MARIGOLDS- Repel Mexican bean beetles, aphids, cabbage moths, potato bugs, squash bugs, nematodes (if dug into soil), and maggots.
CHIVES - Repels aphids and Japanese beetles.
BORAGE - Repels tomato hornworms.
NASTURTIUMS - Repels aphids, potato bugs, squash bugs, striped pumpkin beetles, Mexican bean beetles, and whiteflies.
TOMATOES - Repels cabbage worms.
CELERY- Repels cabbage worms.
ONIONS - Repels carrot flies, but do not plant near beans or peas.
LEEKS - Repels carrot flies, but do not plant near peas or beans.
WORMWOOD - Repels carrot flies and most root maggots.
CATNIP - Repels flea beetles.
RADISHES - Repels cucumber beetles.
GARLIC - Repels Japanese beetles and aphids, but keep away from peas and beans.
GREEN BEANS - Repels Colorado potato beetles.
ROSEMARY-Repels bean beetles, cabbage moths, and carrot flies.
SAGE- Repels cabbage moths and carrot flies.
THYME - Repels cabbage moths.