Cabbage moth control is easier than dealing with cabbage worms, so here we cover prevention and removal.

The term “cabbage moth” is often used to describe both, moths and white butterflies whose larvae as caterpillars are known to be very destructive to cole crops such as broccoli, cauliflower and cabbage.

The Greatest Challenge to Preventive Methods

One of the biggest challenges in most kinds of pest control is that the methods applied may harm other than the target species. For instance, if you employ parasitic wasps, they may also attack butterfly and hummingbird moth larvae and not just the cabbage worms.

So please keep that in mind as you read through these options.

But first, a quick description on cabbage moths you may encounter:

Common Cabbage Moths (listed alphabetically by scientific name)

Hellula rogatalis

Also known as the Cabbage Budworm Moth, the Hellula rogatalis species is primarily found in the southern United States, Central America, and the Caribbean. Its larvae can bore into the buds and heads of cabbage and other related crops, causing substantial damage.

Mamestra brassicae

This moth is the most widely recognized species of cabbage moth. The Mamestra brassicae moth is native to Europe but has since spread to other parts of the world. It’s a part of the Noctuidae (from the latin root nox for night, as this — and most — moths are nocturnal. mo family, a large family of moths.

Plutella xylostella

Also known as the Diamondback Moth, the Plutella xylostella is also a common pest of crops in the Brassicaceae family. Its larvae feed on the undersides of leaves, creating a windowpane effect.

Trichoplusia ni

Commonly known as the Cabbage Looper worm, the Trichoplusia ni caterpillars of this species are known to cause significant damage to a wide range of crops, including those in the Brassicaceae family. They get their common name from their distinctive “looping” method of movement reminiscent of how inchworms move.

While all of these species cause significant damage to brassica crops, their control and prevention methods are similar.

A Note About the Cabbage Moth Scientific Names

The scientific names – Mamestra brassicae, Plutella xylostella, Trichoplusia ni, and Hellula rogatalis – refer to the entire species, which includes both the moth (adult) stage and the caterpillar (larval) stage. In other words, these names are used to refer to the species at any stage of its lifecycle, from egg to larva (caterpillar) to pupa (cocoon) to imago (adult moth).

In casual conversation, people often use common names that can refer to a specific stage of the life cycle. For example, the term “Cabbage Looper” is often used to refer to the caterpillar of the Trichoplusia ni moth. However, in a scientific or formal context, the same universal scientific name is used to refer to the species at all stages of its lifecycle.

Cabbage Moth Prevention

If you’re already seeing cabbage worm destruction, then check out our article on how to get rid of cabbage worms.

Otherwise, preventing the infestation of cabbage moths is your first and best line of defense. Cabbage moths are attracted to plants in the Brassicaceae family for egg-laying, so it’s essential to have your preventative measures in place during these periods.

Preventing the infestation of cabbage moths is your first and best line of defense.

In What Month/s Do Cabbage Moths Appear?

So when should we begin watchful vigilance for cabbage moths looking for places to lay their eggs?

In general, cabbage moths will emerge in the spring when temperatures start to rise consistently, usually above 50 degrees Fahrenheit (10 degrees Celsius).

• In warmer climates (USDA Hardiness Zones 8-11), they can be active for much of the year and may have several breeding cycles.
• In temperate climates (USDA Hardiness Zones 5-7), cabbage moths are generally active from late spring to early fall, with peaks usually in late spring/early summer and again in early fall.
• In cooler climates (USDA Hardiness Zones 1-4), cabbage moths have a shorter activity period, generally from late spring to early fall, with the peak usually in the summer.

Again, these are general guidelines. Weather conditions can vary year by year, and this can affect the precise timing and intensity of cabbage moth activity.

To manage these pests effectively, it’s important to regularly monitor your garden and adjust your pest management strategies accordingly. Local extension services can often provide more specific information based on your exact location.

Begin a watchful vigilance for cabbage moths in spring, especially when temperatures rise above 50°F (10°C).

Strategies for Cabbage Moth Control

Polyculture and Companion Planting

Polyculture is an agricultural practice that involves growing multiple crop species in the same area. This is in contrast to monoculture, where only one crop species is grown. Polyculture can be a highly effective method for preventing cabbage moth infestations for several reasons.

Polyculture Planting

First, the increased plant diversity can make it more difficult for adult cabbage moths to find their preferred host plants (plants in the Brassicaceae family) on which to lay their eggs. In a monoculture of cabbages or related plants, for example, cabbage moths can easily find a suitable host. In a polyculture setting, the presence of other plants can act as a form of camouflage, disrupting the moth’s ability to locate their target plants.

Companion Planting Cabbage Moth Deterrent Plants

PLANTS THAT ATTRACT PREDATORS: For instance, flowering plants can attract beneficial insects, such as parasitic wasps, which are natural predators of cabbage moths.

PEST DETERRENT PLANTS: Polyculture often involves the use of companion plants, which can deter pests or attract beneficial predators.

Cabbage moths aren’t fond of strong and aromatic plants. The scent of these herbs can deter cabbage moths from laying eggs in your garden.

So consider plant herbs like:

• marigolds
• mint
• rosemary
• sage
• tansy
• thyme
• tomatoes
• wormwood

Some of the strongest aromatic mints are mountain mint and peppermint.

Lastly, polyculture systems can create a more resilient ecosystem overall. The presence of multiple plant species can reduce the likelihood of pest outbreaks and can also improve soil health, crop productivity, and the overall sustainability of the agricultural system.

Cover Crops and Crop Rotation

Crop rotation and cover crops are two key agricultural practices that can significantly help in the prevention of cabbage moth infestations. Both methods work by disrupting the lifecycle of the pest and reducing their ability to breed and multiply effectively, and both methods also help maintain soil fertility and can reduce the spread of diseases that affect specific crop types.

Crop Rotation

Crop rotation involves changing the type of crop planted in a particular area from one season or year to the next. This strategy is useful for preventing cabbage moth infestation because the moth’s lifecycle relies heavily on the availability of host plants for egg-laying and larval development.

Cabbage moths, are attracted to plants in the Brassicaceae family, like cabbage, broccoli, and kale. By rotating to a different type of crop, you remove the preferred food source for the larvae, disrupting their breeding cycle and reducing the population.

Cover Crops

Cover crops, also known as green manure, can also aid in preventing cabbage moth infestations. These are plants grown primarily for the benefit of the soil rather than for harvest. Cover crops like clover and buckwheat can attract cabbage moths away from your main crops. Once the cover crop is infested, it can be turned into the soil, thereby killing the larvae before they mature into adult moths.

Another advantage is that some cover crops can attract beneficial insects like parasitic wasps and ground beetles that prey on cabbage moths. This additional benefit of biological control further enhances the effectiveness of cover crops in pest management.

In conclusion, crop rotation and cover crops can form key components of an integrated pest management (IPM) strategy for controlling cabbage moths.

Garden Covers

Use physical barriers such as fine mesh nets or floating row covers to prevent cabbage moths from accessing your plants.

Non-Chemical Control

Trap Crops

Lure cabbage moths away from your main crops by planting a trap crop of plants they love, but away from your garden. Then apply all the other Integrated Pest Management (IPM) tips you can to your main crop, including frost covers.

Here’s a list of plants that can be used as trap crops for cabbage moths, arranged in alphabetical order:

1. Alyssum
2. Buckwheat
3. Clover
4. Corn
5. Kale
6. Mustard
7. Nasturtiums
8. Radish
9. Rapeseed
10. Sunflowers

These plants are known to attract cabbage moths and can therefore be used to draw them away from your main crops.

Once the trap crops become infested, you can then remove and destroy them, (preferably via burning, such as a burn barrel) thereby helping to control the population of cabbage moths in your garden. However, you need to monitor these trap crops regularly to ensure they are effective and that they don’t become a source of larger infestation.

Light Traps

As cabbage moths are nocturnal and attracted to light, you can set up light traps away from your crops. This will lure the moths in and trap them.

Once again, the issue with light traps is that it can also lure the good pollinators, not just the cabbage moths.

Biological Control

Birds and Bats

Encourage birds and bats in your garden by installing birdhouses or bat boxes. These creatures are natural predators of many types of moths and can help control their population.

Parasitic Wasps

These insects are natural enemies of cabbage moths. They lay their eggs inside the moths, and the larvae then consume the moths. Plant nectar-rich flowers to attract these beneficial insects to your garden.

Chemical Control

Pheromone Traps: Use these traps to disrupt the reproductive cycle of the moths. The traps emit a scent that attracts male cabbage moths, preventing them from fertilizing the eggs of the females.

Organic Pesticides: Several organic pesticides on the market are effective against cabbage moths. Always follow the manufacturer’s instructions when using these products.

Synthetic Pesticides: We’re not in favor of this, but include it for those who see it as a last resort. These can be harmful to beneficial insects and your entire yard and garden ecosystem, so use them sparingly and only if you must.

Diligence is Key

Anyone who has ever gardened before will tell you: gardening is rarely if ever a plant and forget endeavor.

It’s vital to regularly inspect your plants for signs of cabbage moths. Implement these preventive cabbage moth control measures to keep your garden healthy and productive.

But… this article should help if you do get cabbage worms.