In companion planting for integrated pest management the technique is to use certain plants as a border or backdrop or to inter-plant them in your flower or vegetable beds where you have specific needs. The use of companion plants that produce copious nectar or pollen in a vegetable garden helps encourage higher populations of beneficial insects that control pests, as some beneficial predatory insects only consume pests in their larval form and are nectar or pollen feeders in their adult form.
Plants with open cup shaped flowers are the most popular with beneficial insects.
Some winning combinations:
SUNFLOWERS:  Aphids a problem? Definitely plant a few sunflowers here and there in the garden. Step back and watch the ants herd the aphids onto the sunflowers. The sunflowers are so tough that the aphids cause very little damage. Sunflowers also attract hummingbirds which eat whiteflies.
DILL:  Best friend for lettuce. The flower heads of dill are one of the best nectar sources for beneficial insects in the garden attracting hoverflies, predatory wasps and many more. Dill also repels aphids and spider mites to some degree. It also repels repel the dreaded squash bug! (scatter some good size dill leaves on plants that are subject to squash bugs, like squash plants.) Dill goes well with lettuce, cabbage, sweet corn and cucumbers.
Plant dill in an appropriate spot for the swallow-tail butterfly caterpillars to feed on. Even their caterpillars are beautiful. However, dill attracts the tomato horn worm so it would be wise to plant it somewhere away from your tomato plant
PUMPKINS: Pumpkin pals are corn, melon, dill, squash and marigold. Marigold deters beetles. Dill may help repel those frustrating squash bugs.
SQUASH: Companions: Beans, corn, cucumbers, pumpkin and marigolds. Helpers: Dill deters worms. Marigolds deter beetles. Dill repels the squash bug that will kill your squash vines. Generously scatter the dill leaves on your squash plants. But Keep squash away from potatoes.
CELERY: Companions: Bean, cabbage family and tomato. The cabbage white butterfly is repelled by the scent of celery so celery is a benefit to all members of the cabbage family.
BROCCOLI: Herbs such as dill, sage and thyme help repel pests of broccoli with their distinct aromas.
SWEET POTATOES:  Aromatic herbs such as dill, thyme etc. are some of the plants that work well with sweet potatoes. They help to confuse and repel the  sweet potato weevil but keep them away from squash. The problem with sweet potatoes and squash is they will compete with each other as they both like to spread out. In fact that is the general problem with sweet potatoes- they take up much room and need full sun. Another idea is to grow them in a container.
THYME: Deters cabbage worms. Woody thyme makes a wonderful groundcover. You may want to use the upright form of thyme in the garden rather than the groundcover types. Thyme is easy to grow from seeds or cuttings. (TO BE CONTINUED)

(By Clifford Stanley )