Radishes and nasturtiums are helpful in repelling cucumber beetles. Catnip can be interplanted with eggplant to discourage flea beetles. Thyme, when planted with cabbage, can repel imported cabbageworms. Onions and chives help repel rust files and some nematodes when planted with carrots. Deadnettle can be planted with potatoes to discourage Colorado potato beetles.
Chives can help repel aphids if planted with roses.
While these companion plantings are not substitutes for chemical control of pests, they can serve as part of a control system. To help manage pests, gardeners should try preventive techniques, detect pests early, correctly identify the pests, choose the proper controls and apply them correctly.