The strong scent and rough texture of dill are off-putting to many garden pests. Insects such as the parsley worm and the carrot weevil may be an occasional problem. Should these troublesome bugs put in an appearance, simply spray the dill plants with garlic- or onion-flavored water two to three times a week until the insects disappear.
Beneficial insects prey on pests, such as mites, aphids and mealybugs. Their presence in the garden keeps pesky, plant-eating bugs at bay, reducing the need for harsh insecticides and pesticides. Beneficial bugs, such as lacewings, ladybugs, hoverflies and parasitic wasps, are drawn to the yard by the flavor and fragrance of the flowers, leaves and seeds of the dill plant.
Dill is a favorite food of many brightly colored butterfly larvae, or caterpillars, including swallowtails and skippers. While the larvae do consume a considerable amount of foliage, many gardeners are willing to tolerate the damage so they can enjoy the presence of beautiful butterflies later in the season.
Apply commercial insecticides with caution. While many products are excellent for getting rid of bugs, they do not differentiate between beneficial insects and serious pests and kill them all. This effectively reduces the number of pollinators in the landscape and can, consequently, negatively impact the production of fruits, vegetables and berries. It is better for the plants, surrounding wildlife and the environment in general to use powerful pesticides only when a serious problem arises, and then only on the affected plants.