How to Treat and Prevent Brassica White Leaf Spot Disease

also known as cercospora Or pseudocercosporellaThere are two different types of fungus that can cause white leaf spot disease on Brassica plants. These diseases affect all plants in the Brassica family, including kale, broccoli, cauliflower, collards, mustard, turnips, radishes, canola, rutabagas, horseradish, and more.

While some plants are more susceptible than others, it is important to root out the potential culprits and causes of this disease.

It is relatively easy to prevent and difficult to treat, so it is important to know ahead of time what kind of threats these fungal pathogens pose.

When temperatures are between 55-65°F, a cold-weather disease, Brassica white leaf spot, is most likely to strike.

Here are some tips to help you ward off Brassica white leaf spot diseases in your plants.

Signs of Brassica White Leaf Spot Infection

How to Treat and Prevent Brassica White Leaf Spot Disease

Several symptoms may indicate the presence of Brassica white leaf spot disease in your plants. The most obvious, of course, are the white spots.

The disease gets its name from the round white spots that appear on the stems, leaves and pods of infected plants.

Darker borders may develop along some centers that eventually rot and fall off. This can give the appearance of shooting your plant with a shotgun.

In addition to spots, many plants also develop yellow leaves that become dry and brittle to the touch. These often wither away completely while attached to the plants – a sight that is quite strange to see.

The lesions on plants are quite superficial. Often, they have different barriers between healthy tissue and diseased tissue. These lesions begin to turn brown and then turn white to ash-brown in color. A large number of dark spots can also be found between the lesions.

On seed pods, the infection begins as small brown spots that later spread and turn a gray to whitish color with dark spots inside.

Causes of brassica white leaf spot

How to Treat and Prevent Brassica White Leaf Spot Disease

A fungal disease, brassica white leaf spot spreads like many other fungal diseases.

It can attack without warning but is most common in plants that are too close together or in certain weather conditions.

For example, wind can spread the spores of these fungi over very long distances, especially in the fall.

This is when conditions are ripe for the spread of the fungus – when temperatures are cool and the weather is wet.

Although fungal spores can spread in almost any season of the year, you may find that spreading is likely to worsen in the fall.

This is because rain during this time of year can cause disease the following spring as the spores overwinter in voluntary crop plants or susceptible weeds.

In places where other brassicas were grown, in addition to overwintering in the soil, brassica white leaf spot can also occur on plants such as wild radish, wild mustard and even shepherd’s purse.

How to Prevent Brassica White Leaf Spot

How to Treat and Prevent Brassica White Leaf Spot Disease

There are a few ways you can prevent Brassica white leaf spot diseases in your garden. Here are some of the best ways to try.

1. Remove Weeds and Plant Debris

The first step you should take is to remove all weeds and other types of plant debris from your garden.

While it is almost impossible to have a garden that is 100% weed free, do your best to promote a garden that is clean.

Brassica white leaf spot can overwinter on Brassica as well as a variety of susceptible weeds. Get rid of any of these plants in your garden, especially those growing near your brassicas.

Also, get rid of plant debris at the end of the growing season. It is tempting to leave plants and plant parts in the garden to rot.

This isn’t always a bad thing, either, because rotting plants provide a valuable source of nutrients (especially nitrogen) to replenish depleted soil at the end of the growing season.

However, they can also harbor fungal spores, so it’s better to be safe than sorry.

Remove plant debris or plow deeply into the soil if you want to be able to harness nutrients while the plants are decomposing.

2. Rotate Crops

No matter what disease you are battling, crop rotation is a good practice. However, if Brassica white leaf spot is an issue, rotating your crops is essential.

If you have planted broccoli in one spot in the garden, do not plant broccoli or other brassicas in the same spot for at least 3 years. It is safe during the fourth year or so.

Rotating your crops is a great way to protect against this disease as well as many other diseases and pests that can affect your plants.

3. Promote good drainage and aeration

How to Treat and Prevent Brassica White Leaf Spot Disease

Brassica, like many fungal diseases, is far more common in gardens suffering from white leaf spot, poor drainage and aeration. Your plants need space to breathe, so give it to them!

Make sure your soil is well draining. The best soil for growing plants is light, fertile and loamy. If your soil has heavy clay, add compost and other amendments until it has the proper composition.

You also need to maintain proper distance between the plants.

There is something to be said about dense planting (for example, it may help reduce weed competition).

However, overcrowding your plants will dramatically increase the likelihood of fungal disease.

When you water, try to do so with drip irrigation lines from below rather than overhead sprinklers.

This will promote faster drying and reduce the chances of foliage getting wet. This is a condition that can increase the spread of various fungal diseases.

4. Clean Gardening Tools

One final tip for preventing this disease is to keep everything – including yourself and your garden – as clean as possible. Sterilize all garden tools with a 10% bleach solution. This should be done after working between infected plants as well as between individual cuts. You must also wash your hands after working with or inspecting contaminated plants.

how to get rid of this fungus

How to Treat and Prevent Brassica White Leaf Spot Disease

The best way to get rid of brassica white leaf spot is to prevent it. However, if you notice it later, this irritating fungal disease can be perpetuated as well. The key to being successful in your treatment is to act as quickly as possible.

Spray copper fungicide as soon as you notice any signs or symptoms of this disease.

It should be applied on the underside and upward side of the leaves. It needs to be reapplied once every 7-10 days until the disease is gone.

Bennalate is a good product to consider, but it is important to note that this chemical can be toxic to some cruciferous vegetables (such as cabbage).

Therefore, it may be worth checking with your local cooperative extension to see what treatments are recommended in your area.

Will Brassica White Leaf Spot Kill My Plants?

How to Treat and Prevent Brassica White Leaf Spot Disease

A unique feature of Brassica white leaf spot is that, while it can affect all cruciferous plants, it does not affect them all equally.

Kale, cauliflower, broccoli and collards usually contain at least affected by disease. Other brassicas seem to have more hits. For example, canola is extremely weak.

Whether or not your plant will survive depends largely on its overall health before it became infected.

White leaf spots cause reduced chlorophyll production as the green areas on the plants disappear. Soon after, the leaves turn yellow and die.

If your plant is healthy and old, it can usually survive the loss of leaves. However, if this disease threatens seedlings, it can severely deform them or even kill them completely.

Therefore, if you notice this fungal disease in your garden, it is important to act fast. This is true, especially if it is early in the growing season.

With the right preventive care, it can usually be eliminated.

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