Cabbage Moth

Gardeners are no strangers to pesky Cabbage Moths.

This nondescript-looking moth wreaks havoc on a variety of vegetables. While they are named for one of the plants they deem tastiest, gardeners know that they can be found on everything from broccoli to tomatoes. With a widespread area, many people are familiar with these pests. Learn where they live, how they become pests, and what they eat so that you can take steps to protect your harvest.

Species, Types, and Scientific Name

The Cabbage Moth, known scientifically as Mamestra brassicae, is part of the Noctuidae family. This family of moths is also known as owlet moths. The Noctuidae family is the second-largest family of moths with over 11,000 species. The Mamestra brassicae is just one of many species of moths. But due to their impact on crops and plants, they are one of the better known.

All moths, including Cabbage Moths, belong to the Lepidoptera order. This also includes butterflies. While there are many similarities between moths and butterflies, there are key differences as well. Moths are generally duller in color compared to brightly-colored butterflies. This applies to the brown Cabbage Moth. They extend their wings over their bodies while at rest. This behavior is one of the easiest ways to identify a moth versus a butterfly.

Cabbage Moths are not the same as Cabbage Butterflies. Although they do have similar behavior and host plants, Cabbage Butterflies are an entirely different species. Cabbage Butterflies, scientific name Pieris rapae, belong to the Pieridae family. Cabbage Moths, or Mamestra brassicae, belong to the Noctuidae family. Both are part of the Lepidoptera order.

Appearance: How To Identify Cabbage Moths

Unfortunately for gardeners, the Cabbage Moth does not have a lot of distinctive markings that are easily recognized. They are roughly 1.5 inches long, similar to many other moths. They have four wings: two forewings and two hindwings. These are mostly brown with some black and white spotting and banding. They can have a white stripe near the edge of their wings that helps identify them as Cabbage Moths, although this may not be very pronounced.

Cabbage Moth caterpillars are green with some black and brown markings. These become more pronounced as they grow and mature toward the end of the larvae stage. When they are ready to transform into adult moths, they form brown pupae.

Cabbage moths look very similar to other moth species in both the larvae and mature adult forms. This can make them hard to identify by sight. One of the best ways to tell if you are dealing with Cabbage Moths is to consider the impact that they have on plants. Larvae feed on the leaves, often staying on the underside and close to the ground. If you notice that something has been eating your cabbage, broccoli, tomatoes, or sunflowers, look around for larvae that could be cabbage moths.

Habitat

These moths live in Europe and Asia. They can even survive in parts of Africa. Due to the plentiful nature of their preferred foods, either through native growth or cultivation, there is plenty for these moths to eat. They have grown and developed to live in many areas.

Cabbage moths are not a pest known in the United States. However, the importation of vegetables and live plants always increases the risk that they will spread to other parts of the world. The climate in other parts of the world, including North America and South America, is conducive to Cabbage Moth’s survival and expansion. For this reason, growers must be very careful about inspecting incoming plants for cabbage moth eggs and larvae.

Generally, the adult moths cannot fly far enough or survive long enough to spread to new parts of the world in that form. More often, eggs and larvae attach to plants and travel to new areas in that way.

Diet

These moths are not picky eaters. This means that they eat a wide variety of plants. Many are low-lying to the ground, such as cabbage and broccoli. Others can be higher up, including sunflowers. Many of the foods that Cabbage Moths enjoy are cultivated in gardens. These can be small-scale home gardens or larger commercial plots. Either way, when Cabbage Moths are introduced, gardeners and farmers are quick to get their population under control before they decimate crops.

Plants that Cabbage Moths enjoy include cabbage, cauliflower, broccoli, spinach, and lettuce. They also like vine-growing plants, such as tomatoes and peas. Cabbage moths can also eat tobacco and many other plants that have larger commercial implications beyond home gardens.

When they feed, Cabbage Moth larvae eat the crops directly as well as the leaves. They burrow into the plant and consume it, leaving behind their own waste products. They are more active at night, making them hard to spot during the day. If you find that your plants are getting eaten each night, you may be dealing with Cabbage Moths.

Prevention: How to Get Rid of Cabbage Moths

Like getting rid of any pests, finding them early is very important. The female Cabbage Moths lay their eggs, often up to 350 at a time, on the underside of leaves. These large clutches of eggs result in a large number of hungry larvae when they hatch. Eggs take around a week to hatch. If you see a clutch of eggs or larvae on your plants, simply pull them off and discard them.

One great way to get rid of cabbage moths is to attract their predators to your garden. Birds, including chickens, love to eat the larvae form of Cabbage Moths. If you live in an area that supports keeping chickens, adding these birds can be both fun and beneficial. Just keep in mind that they come with their own needs that you will have to consider.

If you don’t want to keep your own flock, you can also attract wild birds to your garden area. Birdseed, birdbaths, and birdhouses all help wild birds feel right at home. Many also eat the larvae form of Cabbage Moths.

Some species of wasps can also impact the growth of Cabbage Moths at various stages in their larvae form. Introducing wasps to your garden as a means of pest control, however, is best left to experienced gardeners.

Finally, insecticides can prevent and kill Cabbage Moths. It can also impact beneficial insects so we recommend this as a last resort. If treating your plants with insecticides, make sure to get the underside of the leaves since this is where the eggs will be. It is also important to rinse your vegetables before consuming them.

1. Cabbage Butterfly, Available here: https://www.baag.com.au/cabbage-white-butterfly-and-cabbage-moth/
2. USDA Butterflies and Moths, Available here: https://www.aphis.usda.gov/aphis/ourfocus/planthealth/import-information/permits/plant-pests/sa_butterflies_moths/butterflies-moths
3. Wildlife Insight, Available here: http://www.wildlifeinsight.com/british-moths/cabbage-moth-mamestra-brassicae/