What Pesticide Kills Rose Black Spots?

what pesticide kills rose black spot

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If you are tending to rose bushes in your garden, you know the importance of keeping your plants healthy. Black rose spots are one issue that gardeners frequently deal with. These unsightly blemishes can ruin the appearance of your plants.

If you’re looking to control this plant disease, then you may be wondering what pesticide kills black rose spots. Read on, and we’ll tell you everything you need to know about this disease and how to control it.

What Causes Black Spots on Roses?

diseased leaves, petals and rose flowers stained with spots. Close-up macro, rot and pests roses

Black rose spots are unsightly blemishes that can ruin the appearance of your plants. Commonly called the rose black spot disease, this problem is caused by a fungus called Diplocarpon rosae.

This fungus attacks the leaves and stems of roses and other members of the Rosaceae family, such as cherries, apples, and pears.

Black spot disease is most commonly found in humid climates and can quickly spread from one plant to another. If left untreated, this plant disease can cause the leaves of your rose bush to turn yellow, brown, or black. The spots will often grow in size and number over time, and the leaves will eventually drop or fall off.

How Does the Rose Black Spot Disease Spread?

The rose black spot disease can spread quickly in your garden if you don’t take precautions. Spores produced by black spots can be dispersed by the wind, rain, insects, or gardening equipment. Hence, if you don’t clean your tools and equipment after using them in infected areas, the spores quickly spread to other parts of your garden.

The spores are also spread by wind and rain. If you reside in a region where it rains often, the spores can quickly spread to your plants. And if you have windy conditions in your area, the spores can be blown onto your plants from other gardens.

How to Identify the Signs of Rose Black Spot Disease

If you are unsure whether or not your plants have black spot disease, there are a few things to look for. The most noticeable signs of this problem include the following:

Yellowing Leaves

One of the earliest signs that your garden plants are infected with black spot fungal disease is the appearance of yellow leaves. You may notice that the edges of the rose leaves turn yellow first, and then the colour moves inward. The entire leaf may turn yellow as the disease progresses and then fall off.

Black Spots on Rose Leaves

The most telltale sign of black spot disease is the presence of black spots on the leaves. These spots may be small or large, and they often have a yellowish halo around them. As the disease progresses, these spots will become more numerous and may eventually cover the entire leaf.

Wilted or Drooping Leaves

If your once-healthy rose leaves are wilted or drooping, it’s a good indication that something is wrong. This may be a sign of black spot disease and other problems such as aphids or spider mites.

Stunted Rose Bushes

If your rose bushes look smaller than usual, it’s possible that they have black spot disease. This problem can stunt the growth of your plants and make them look much less healthy.

Once you have identified the fungus causing the black spots on your rose plants, it is vital to take action immediately. The sooner you start treatment, the greater chance you have of saving your plants.

Ways to Treat Black Spot on Roses

withered roses with black spots in the garden

Rose black spot disease can cause significant damage to your plants, so it is important to treat it as soon as you notice the symptoms. If you’re wondering what pesticide kills rose black spot, there are several options available, including:

  • Mancozeb
  • Dithane M-45
  • Penncozeb
  • Zineb

All of these fungicides are available in either liquid or powder form. You can also buy them pre-mixed products, such as Mancozeb Plus Zinc.

When choosing treatment for ornamental plant diseases, read the product label to make sure it is registered for use on roses and that it will control black spot disease.

However, if you want organic fungicides, below are some of the best ones to use:

Bordeaux Mixture

This mixture is made from copper sulfate and hydrated lime. It is a contact fungicide, which means it must come in direct contact with the fungal spores to be effective. Bordeaux mixture can be used on both organic and conventional roses.

To make your own Bordeaux mixture, mix one cup of copper sulfate for each gallon of water with 1/2 pound of hydrated lime for each gallon of water. Stir the solution well and let sit for 24 hours before using.

You can also buy Bordeaux mixture as a pre-mixed product.


Another organic treatment that can treat black spots on roses is milk. Milk contains proteins and minerals that are toxic to the fungus. To use milk as a fungicide, mix one part of skim milk with nine parts of water and spray it on your roses.

Be sure to reapply the milk mixture every seven to ten days for the best results.

Organic Soaps

You can use several organic soaps to control black spots on your shrub roses. These soaps work by suffocating the fungus. To use an organic soap as a fungicide, mix one tablespoon of soap with a gallon of tap water and spray it on your roses.

Some good organic soaps to use are:

  • Dr Bronner’s Castile Soap
  • Ivory Liquid soap
  • Murphy Oil Soap

Zinc Sulfate

Zinc sulfate is also used for treating fungal plant disease. It is available as a powder, liquid or foliar spray.

Neem Oil

Neem oil is a natural substance that comes from the seeds of the neem tree. This oil has a wide variety of uses, including as a pesticide.

Neem oil can help suppress black spots on roses by mixing them with water and spraying them on the affected leaves. This treatment should be repeated every seven to ten days until the black spots are gone.


Sulfur is a naturally occurring element that can also treat black spot disease. To use sulfur, mix it with water and spray it on the leaves of your plants. Sulfur can also be a preventative measure by spraying it on the plants every few weeks.

Baking Soda

Another option for treating black spot disease is baking soda. This natural remedy can be used to both prevent and treat fungus. To use baking soda, mix one teaspoon of baking soda into a quart of water. Soak the entire plant in this mixture for about fifteen minutes, then rinse them off with clean water.

Apple Cider Vinegar

Another natural option for treating black spot disease is apple cider vinegar. This organic solution can be used either as a preventative or treatment.

Mix one-part apple cider vinegar with nine parts water to use apple cider vinegar. Soak plant leaves in this mixture for about fifteen minutes, then rinse them off with clean water.

These fungicides will help control black spots and other diseases, such as powdery mildew and rust. By using one of these products, you can keep your roses healthy and disease-free.

How to Treat Black Spots on Roses With a Fungicide Spray

If you have black spots on your roses, it’s essential to treat them with a fungicide as soon as possible. If left untreated, the disease can quickly kill a rose bush and spread to other plants. Here’s a step-by-step guide on how to get rid of black spots on roses:

Step 1: Pick Your Treatment Product

Different fungicides can treat black spots, including organic and conventional sprays. 

However, no matter what you choose, read the label carefully. This will instruct you on how to use the fungicide.

Step 2: Prune the Infected Plants

The most critical steps in this treatment process involve removing diseased leaves, infected stems, as well as infected canes. This will help to stop the disease from spreading.

Step 3: Get Rid of Fallen Leaves and Debris

The next step in the process is to remove any dead leaves or debris around your plants. This will help eliminate any places where the fungus can live and thrive.

Step 4: Apply the Fungicide

Once you have pruned your roses and removed any fallen leaves or debris, it’s time to apply the fungicide. Follow the directions on the label carefully. This will ensure that you are using the product correctly and safely.

You will have to use the fungicide spray weekly for two to three months to get rid of the black spots.

Step 5: Monitor Your Rose Bush

After applying the fungicide, it’s essential to monitor your plants closely. Be sure to check for new growth and signs of the black spot fungus. If you see any new signs of black spots, repeat the treatment process.

Follow this step-by-step guide on treating black spots on roses and keeping your plants growing well and beautifully.

How to Prevent Rose Black Spot Disease

The best way to eliminate black spot disease from your roses is to prevent it from happening in the first place. Here are a few simple steps you can take to reduce the risk of your plants becoming infected:

Water Early in the Day

Water your plants in the morning so that the leaves have time to dry off before nightfall. This prevents the fungus from taking hold.

Prune Infected Leaves

If you notice any leaves infected with black spots, be sure to remove them from your plant. This will help to prevent the spread of the disease. You can either dispose of the leaves in the trash or burn them.

Avoid Overhead Watering

Don’t water your plants from overhead, as this can cause water droplets to fall on the leaves. Water the roots of your plants instead. This aids in keeping the leaves dry and reducing the chances of spreading the fungal infection.

Promote Air Circulation

Make sure that your roses have plenty of air circulation. This will help dry the leaves off quickly and reduce the risk of fungal diseases. You can do this by seeing to it that your roses are spaced out appropriately.

Make Sure Your Roses Get Plenty of Sunlight

Roses prefer to grow in full sunlight, so make sure that your plants get at least six hours of sun each day. This will also help to prevent the growth of black spot fungus.

Choose Resistant Varieties

When selecting roses for your garden, be sure to choose varieties that are resistant to black spot disease. Examples are “Belle of Port Deposit” and “Climbing Pinkie”.

The flower grower must always check plants that do not have black spots. Disease-resistant roses can be planted into hardy roots to produce new plants which will grow quickly and be resistant to most diseases. They can also produce new rose species by crossing two kinds of naturally resistant ones.

Disinfect Gardening Tools

Be sure to disinfect your gardening tools after each use. This will help prevent the spread of disease from one plant to another.

Clean Your Rose Garden Regularly

Make sure to clean up plant debris and fallen leaves regularly, particularly in the fall. This ensures that there’s no overwintering host for the fungus. The fungus spores can survive even a harsh winter, so take these steps to prevent them from returning the following year.

Apply Mulch Around Your Roses

Applying a layer of mulch around your roses can help to prevent black spots. Mulch will help prevent splashes, effectively reducing the spread of spores from the ground from reaching your plants.

Things to Consider When Using Fungicide Sprays

Fungal sprays are effective for black spot treatment. However, they should be used with caution. Here are a few things to keep in mind when using fungicide sprays:

Only Use Products Labeled for Roses

Use products that are labelled for roses. Using the wrong product can damage your plants and make the problem worse.

Follow Directions Carefully

Follow the directions on the fungicide spray bottle carefully. Using too much or too little of the product can be ineffective and may even damage your plants.

Consider the Life Cycle of the Fungus

When using a fungal spray for roses, take into account the life cycle of the fungus. There are three stages in the fungus life cycle: spore production, germination, and infection. The fungicide needs to be applied during at least one of these stages to be effective.

Apply the fungicide during the germination stage, which typically takes place seven to ten days after the fungus has infected the plant. However, keep up with your weekly spraying schedule since it can be challenging to know when this stage occurs.

Keep Safety in Mind

Also, it would help if you keep safety in mind. Wear gloves, goggles, protective clothing, and a face mask when applying the fungicide, and avoid getting it on your eyes and skin. Wash your hands thoroughly afterwards.

Always keep pets and children away from your garden until the fungicide has had a chance to dry. Fungicides can also be harmful if ingested, so it’s important to take these precautions.

Don’t Spray When it’s Windy

It’s important to avoid spraying fungicide when it’s windy, as the product can drift and cause damage to other plants.

Wait Until Dusk to Spray

The best time to spray fungicide is in the evening, just before dusk. This gives the product time to dry on the leaves before nightfall.

Apply at First Sign of Black Spots

Be sure to apply the fungicide at the first sign of black spots. The sooner you treat the problem, the more likely you are to get rid of the fungus.

If you follow these steps, you’ll be well on your way to getting rid of black spot fungus in your garden. Be patient, as it can take some time for the fungicide to work its magic. In the meantime, enjoy your beautiful roses!

Frequently Asked Questions

What is Black Spot Disease?

Black spot disease is a fungal infection that affects roses. The fungus causes lesions on the plant’s leaves, which can eventually lead to death if left untreated.

How Do I Know if My Hybrid Tea Roses Have Black Spots?

The most common symptoms of black spots are dark spots on the leaves of the plant. The spots may be small at first, but they can grow larger over time. The leaves may also wilt and fall off the plant.

Is There a Cure for Black Spots?

Black spots can be treated with fungicide sprays. It’s important to catch the infection early and treat it with a fungicide formulated to treat black spots.

How Often Should I Spray My Plants With Fungicide?

Maintain your weekly spraying schedule when using a fungicide to prevent black spot disease. Apply the fungicide during the germination stage, which typically takes place seven to ten days after the fungus has infected the plant. However, since it can be challenging to know when this stage occurs, it’s important to keep up with your weekly spraying schedule.

What Should I Do if My Plants Have Already Been Infected With Black Spots?

If your plants have already been infected with black spots, it’s vital to treat them with a fungicide. Be sure to follow the directions on the label carefully and apply the fungicide at the appropriate time in the fungus’ life cycle.

Can I Prevent Black Spots From Happening?

Pruning rose bushes in the fall. Garden work. The pruner is in the hands of the gardener. High-quality photo

There are several simple steps you can take to help prevent black spot disease from occurring, such as watering early in the day, removing infected leaves, cleaning your garden tools, and applying mulch around your roses. Fungicide sprays can also be effective in preventing the disease.

Is It Safe to Use Fungicide Around Pets and Children?

When used properly, a fungicide can be an effective way to prevent black spot disease. However, keep safety in mind when using any chemical. Wear gloves and a face mask when applying fungicide, and be sure to wash your hands thoroughly afterwards. Keep children and household pets away from your roses until the fungicide has had a chance to dry.

Where Can I Buy Fungicide?

Fungicides are available at most garden stores. Be sure to read the label carefully before making your purchase to ensure you are getting the right product for black spot disease.

What Is the Life Cycle of Black Spot Fungus?

The life cycle of black spot fungus can vary depending on the type of fungus. However, it typically takes seven to ten days for the germination stage to occur. During this stage, the fungus will infect the plant and start to grow. It’s important to apply a fungicide at this time to prevent the disease from spreading.

How Long Does Fungicide Last?

Fungicides generally have a shelf life of two years. Be sure to check the expiration date on your bottle before using it.

What Should I Do if I Accidentally Spill Fungicide on My Plants?

If you accidentally spill fungicides on your plants, be sure to wash them off with water immediately. Do not allow the fungicide to dry on the leaves.

What Is the Best Organic Rose Black Spot Treatment?

There is no definitive answer to this question, as there are many different organic fungicides on the market. However, some of the most common organic fungicides for black spot treatment include neem oil, sulfur, and copper sulfate. Be sure to read the label carefully before making your purchase to ensure you are getting the appropriate product.

How Do I Make a Homemade Remedy for Black Spots on Roses?

There are many different recipes for homemade black spot remedies, but one of the most common is to mix two tablespoons of baking soda with one gallon of water. This mixture can then be sprayed on your plants once a week to help prevent the disease from occurring.

Treating Rose Black Spots on Roses Effectively

Roses add beauty to any garden, but they are susceptible to several diseases, including black spots. Thus, it is important to treat the fungal disease as soon as the first signs appear.

This guide answered the question, “What pesticide kills rose black spots?” and included tips on treating infected plants. With proper care and treatment, you’ll address this problem and keep your plants healthy!

Do you have any tips for treating black spots on roses? Share them with us in the comments below!

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