Cabbage aphids (Brevicoryne brassicae) can severely damage young crops in hot, dry climates. Luckily, their interests are confined only to plants in the brassica family—like cabbage, broccoli, and cauliflower—and wet or moderate climates tend to control their growth. Left unchecked, however, they can easily ruin a crop.
Cabbage aphids, sometimes called mealy aphids, are small white bugs that feed on brassica crops in large numbers. Like the common aphid, they feed on the sap of a plant, which means they can do damage to nearly any exposed part of your crop.
Cabbage aphids make themselves known in much the same way that regular aphids do. They are usually a whitish-grey color but can also appear black. They group together in thick clusters to feed.
If you miss the cabbage aphids themselves, your plant will let you know that it’s under attack in several ways.
Cabbage aphid infestations will result in yellow or white leaves. Oftentimes, the leaves also curl or become otherwise misshapen.
Aphid-infested brassicas will typically grow slowly or incompletely. Their edible heads—like the sprouts on a brussels sprout plant—may appear damaged, stunted, or sickly.
Unfortunately, once cabbage aphids have appeared, they can be more determined to hold their ground than other aphid types.
One of the best ways to control them is by introducing (or allowing) aphid predators to control their populations. These include:
Some of the more popular organic aphid control methods may be effective on cabbage aphids. Try:
Cabbage aphids can be persistent, so some people prefer to go the non-organic (insecticidal) route.
Of course, the best way to control aphids is to keep them from showing up in the first place. If you’ve had a cabbage aphid infestation, remove all affected plants at the end of the season (and don’t add them to your compost—remove them from your property altogether). Cabbage aphids can overwinter, so keeping old plants around is inviting a cold-weather guest.