This image shows a small infestation of aphids (tended by ants) on cabbage. Even this few aphids shows how much damage they can do. When they suck the juices from the leaves, the leaves curl and are deformed. As the colony gets larger, the plant is stunted, and produces a lot less, if at all.
Although ants are annoying when they come indoors, they can be beneficial by feeding on fleas, termites, and other pests in your garden. But also, ants are often associated with aphid populations, especially on trees and shrubs, and frequently are a clue that an aphid infestation is present. In our veggie gardens, aphid favorites are broccoli heads, curly leaf kale leaves, young cabbage leaves. Last spring they just about killed all our artichokes throughout the garden, and, alas, they spread from my neighbor’s plot to my okra flowering heads.
Managing ants is a key component of aphid management, because not only do they feed on the honeydew, but they protect the aphids from other predators! Hose off the aphids – daily, until they are gone. Be sure to get the undersides of leaves. If you can’t get them gone from broccoli heads or the tight curly leaf kale leaves, remove those parts of the plants. Catch them while they are small colonies or, sadly, you may find yourself having to remove the whole plant. Keep watch for the curled leaves that should be more flat, distorted leaves, or that little gray look…or little black dots, tiny black aphids. Clever little devils come in different colors! Ease up a bit on fertilizing and watering, making very soft bodied easy to eat leaves.
Ant nests may also be associated with plants that support large populations of other honeydew-producing insects – soft scales, mealybugs, or whiteflies. Whiteflies are easy to see. When you tap the plant a cloud of them will fly off. Hose them away too, getting up under those leaves. Keep ant nesting materials like mulch away from the base of your plants, and keep the area weed free, especially of grasses. Avoid over watering – ants will nest near a water source.
Chemical baits are not ok in our organic veggie garden. But a simple remedy can be putting a few drops of dish soap around and filling the nest entrance.
Ants, bless them, are Nature’s fast and efficient cleaner uppers. Odds are against ant free gardens. But we can have less of them.