How to Deal With Cabbage Mosaic Virus Disease

Don’t be fooled by the name, Cabbage Mosaic Virus attacks far more plants than just cabbages, and it can be a challenge to deal with once it infects your garden.

In a good year, your cabbages, nightshades, and cucurbits can grow without trouble. But some years for whatever reason a pathogen takes hold. When that happens, growing your favorite veggies becomes a bit more challenging.

A few years ago, aphids went wild in our garden. We started battling them in June and didn’t stop until the frost killed them. It was a tough year, and they brought Cabbage Mosaic Virus with them. It decimated our brassicas and cucumbers. Here’s what to know:

What is Mosaic Virus?

Growing cabbages can be incredibly simple. Unlike many other plants, cabbages are straightforward, consistent producer. Maybe that’s why cabbages are a staple in so many diets.

But any plant that’s been grown for thousands of years is bound to pick up a few diseases, and along the way, a virus developed that specifically targeted these plants.

There are actually a variety of mosaic viruses that can impact cabbages: Turnip Mosaic Virus (TMV), Cucumber Mosaic Virus (CMV), and Cauliflower Mosaic Virus (CaMV). While each of these viruses belongs to a different “family” of viruses, they’re all spread by aphids, and they all cause similar symptoms.

We’re going to focus on Cucumber Mosaic Virus, which can also affect melons, celery, beans, and nightshade plants like tomatoes, corn, eggplants, and potatoes. But if you have something attacking your plants that sounds like a mosaic virus, don’t worry about which specific one it is. The symptoms and steps to handle the disease are all the same.

An infected plant starts to develop yellow rings on the newest leaves. As it progresses, the whole leaf takes on a mottled look – like a mosaic where the light is hitting different tiles all at once. In a true mosaic, the effect is lovely. It gives depth to the overall image. On most veggies, the plants tend to look slightly bruised and discolored.

The virus continues to spread, causing mottled rings, blotches, and even black, necrotic patches. Eventually, your cabbages, melons, or tomatoes look like a boxer, fresh out of the ring, with bruises and black eyes. It’s not an appetizing end product, that’s for sure.

Without quick care, that gorgeous row of cabbages is good for nothing by harvest time. There’s no cure for any mosaic virus, but there are a lot of ways to stop the spread and help your plant resist the disease.

Like any disease, a healthy immune system can go a long way in reducing symptoms.

Methods of Infection

Aphids are the most common means of infection for most plants, but they’re not the only cause. Other common, garden pests like leafhoppers and cucumber beetles can spread it as well.

CMV can also overwinter in the garden. If some of your plants (or even some weeds) had a mild case of Cabbage Mosaic Virus, the pathogen will linger all winter long – waiting to infect again.

It also hitches a ride on tools like pruners, shovels, and even your gloves.

CMV is very communicable within the susceptible species. Even touching a leaf of an infected plant to a healthy plant is enough to cause the virus to spread.

With that in mind, it’s easy to see just how many causes might be behind an outbreak of Cabbage Mosaic Virus. A messy garden, unclean tools, and pests can all be the cause of an outbreak.

Reducing Infection Opportunities

When a virus spreads so easily, it can be difficult to pinpoint the cause. The best way to reduce the risk of a year of ruined veggies is to reduce the virus’s opportunities to infect. Start by making your garden as inhospitable to pathogens as possible.

Clean Up!

I say it all the time because it’s the best way to maintain a healthy garden: Clean up those leaves, weeds, and dead plants.

Pathogens of all kinds can thrive in the organic mess of the garden. In the fall, put your garden “to bed” by raking, weeding, and cleaning. Tarp over problematic areas to kill off invasive plants or prep the area for solarization in the spring.

A clean garden is a healthy garden. Putting your garden to bed in the fall seems like a lot of work for no payoff. After all, you can do it all in the spring just as easily!

But taking the time to prep your garden for winter reduces the risk of disease exponentially. Wash your garden tools and keep them clean. Don’t leave rakes and trowels among the weeds in your garden.

Destroy Infected Plants

Don’t just pile infected plants off to the side. Don’t leave them to rot in the garden beds. Definitely don’t toss them into the compost bin. Infested plants are carriers of disease.

Once the virus has run its course on one plant, it wants to spread to another. If you don’t dispose of infected plants properly, you’re just helping the virus find a new host among your healthy fruits and veggies.

Burning is the best way to destroy plants infected with mosaic virus. If you can’t burn your plants, put them in a plastic trash bag and take them to the dump.

Cover Up

Aphids, leafhoppers, and other common pests are quick to spread Cabbage Mosaic Virus, because all it takes is one bite. That’s why row covers can be a crop saver. Use row covers during the early season to keep pests off your plants.

These first couple of months of safety from pests can make a huge difference to your plants. Row covers keep them safe so they have the time to grow strong roots and absorb plenty of nutrients. Then, with a healthy start, they’re less likely to succumb to the virus.

Just remember to remove the covers or hand pollinate your plants during flowering time or you might not end up with any fruits or veggies on the plant.

Careful Gardening

When you’re working in the garden, avoid habits that might aid in spreading the virus. Don’t work around susceptible plants in the rain. Viruses can spread quickly when it’s wet because the water provides a carrier. In humid, damp, or drizzly weather, stay out of the garden or work with non-susceptible plants.

You should also clean your tools when you move from one plant to another. It might seem like a lot of work, but the virus can be carried on pruners or shovels from one plant to the next.

To make things easier, carry a rag soaked in dish soap and water with you in the garden and wipe your tools regularly.

Don’t forget to plant at an appropriate distance to minimize crowding.

Pest Control

Keep aphids and other virus-spreading pests at bay with insecticidal soap, trap crops, netting, and neem oil. The fewer sapsucking insects you have in your garden, the lower the chance of Cabbage Mosaic Virus spreading.

There are so many ways to reduce the aphid population in your garden – everything from trap crops to lure them away from your garden plants to commercial pesticides. Try to keep your response measured but consistent.

Plant Mosaic Virus Resistant Varieties

There are plants out there that can resist CMV. When it comes to cucumbers, check out ‘Freeman’s Cucumber’ and ‘Songwhan Charmi.’ The bell pepper ‘Perennial’ is also resistant. There are no resistant tomatoes, unfortunately.

Many of the Danish cabbage cultivars have a stronger resistance to CMV. The cultivar ‘Danish Ballhead’ stands out as the most consistently resistant. Of course, any resistance is better than no resistance, so if you have the opportunity to bring in any resistant variety of cabbage, don’t hesitate.

Is There a Cure?

There is no cure for Cabbage Mosaic Virus. Once it takes hold, you can only minimize the damage.

Once you find infected plants, the best thing to do is cover them entirely and remove them from the garden. Pulling out and disposing of infected plants early on can help save some of the nearby plants.

Can I Eat Plants Infected with Cabbage Mosaic Virus?

Yes, you can eat plants infected with CMV. There’s no risk of spreading the virus to people or animals since it’s species-specific. I’ve given infected veggies to my livestock. I’ve also cut away the affected parts of a cabbage and used the rest in cooking.

There’s no denying that CMV damages your plants. It reduces yield and it leaves you with unsightly, mottled produce. But most of the time, you can still find something to salvage from infected plants. You can even eat the ugly, damaged bits if they aren’t rotted.

If you do choose to eat infected plants, remember not to put the food waste into the compost! Even though that part of the plant looks fine, it is still infected. Put food scraps into the garbage, burn them, or give them to livestock. Don’t let them re-infect your garden.

Can I Save Seeds from Cabbage with Mosaic Virus?

The short answer is: No. Don’t save seeds from infected plants. The seed will carry the virus to next year’s garden. If you have an infested crop, buy entirely new seeds for next year’s garden. Destroy all the stalks and roots of the infected plants and start fresh.