There are several plants that will help repel summer pest insects.
Catnip – 10 times more effective than DEET (a bug repellent chemical), catnip loves sunny locations with well-drained soils. This perennial herb produces gray-green foliage with soft blue flowers.
Marigolds – While this flower may not have the best scent, marigolds work well in vegetable gardens because they act as a repellent and as a “trap” plant. In other words, they themselves are feasted on instead of the vegetables you’ve planted and they do repel insects like aphids. They are also attractive to beneficials that prey on aphids. Marigolds and their bright orange, yellow and red blossoms like plenty of sun.
Lemon Thyme – Speaking of fragrance, lemon thyme emits a clean lemon scent that’s popular with humans, yet extremely unpopular with insects. This evergreen perennial is hardy in zones 4-11 and prefers full sun. It’s drought-tolerant, spreads quickly, and looks a lot like English thyme.
Lemon Basil – Another aromatic herb, this finicky annual is covered with small flowers and needs to be watered regularly. It’s a good addition to any vegetable garden for its ability to deter white flies and also enhance the flavor of tomatoes.