The vegetable known for its ability to repel insects is the marigold. Although marigolds are actually flowers, they are often treated as companion plants in gardens due to their pest-repelling qualities. They emit a scent that many insects, particularly aphids and nematodes, find unappealing, thus helping to protect neighboring plants. Marigolds are often planted alongside vegetables and flowers to naturally deter harmful pests and promote healthier garden ecosystems. Additionally, they attract beneficial insects like ladybugs and pollinators, making them a valuable addition to any garden seeking to reduce reliance on chemical pesticides.