Certain essential oils serve as the perfect organic pest control for garden vegetables. For example, you can use peppermint oil against squash bugs, beetles, fleas, aphids, spiders, and ants. Clove oil works against various flying insects. To deter slugs and snails, use cedarwood and pine oils. To prevent fleas, flies, and larvae such as the cabbage looper caterpillar, use rosemary oil. Neem oil is a popular pest repellent that works against 200 species of insects.