Black spot is a Rose disease that is caused by the Diplocarpon Rosae fungus. The disease spreads between the leaves and can effectively kill all foliage on your Rose bush. This can cause it to be more susceptible to other diseases and even increase winter damage.
The main symptom of the black spot disease is small black spots on the leaves that grow gradually in size. Normally you will see a yellow halo around the spot on the affected leaf that will gradually turn the whole leaf yellow. You will also notice the leaves falling off before autumn, which is a tell-tale sign that something is wrong.
The only way to control this disease is by removing affected leaves and branches and disposing of them. Be sure that you also dispose of the dead leaves that have fallen off the bush for this reason. Cut back affected branches a few inches into good wood to ensure that the issue is removed.
To prevent this disease, take a look at our Rose diseases photos and make sure that you know what it looks like. Applying fungicide to your Roses will also help prevent black spot from occurring. An application once or twice a week will help keep your Rose bush healthy and happy. Check out our Rose diseases photos if you believe you might be infected.
Powdery Mildew is a Rose disease that is caused by the fungus Sphaerotheca Passnosa. Young leaves will curl and turn purple while canes will become dwarfed. If not treated, the affected areas will die over time. It is easy to spot this disease by looking for a white powdery coating over the foliage of your Rose.
The white fuzzy substance on the leaves is comprised of tiny fungal spores. Those spores can blow around in the wind and spread to other young leaves. The mildew then develops rapidly and continues to spread. Warm and humid conditions make Powdery Mildew expand rapidly.
To combat this disease, spray the affected areas with fungicide to kill existing spores. If you cannot kill existing spores, remove the infected areas and dispose of them properly.
To prevent Powdery Mildew, keep your plant clean by removing all dead foliage before it rots. Spray new growth with fungicide immediately. New growth is the most susceptible, so it is important to protect it as soon as possible. Check out our list of Rose diseases photos if you think you might be affected.
This disease causes flower buds to droop and remain closed. The buds will then turn brown and decay over time. Caused by the fungus Botrytis Cinerea, your Rose can quickly get covered in a gray fungus if not dealt with.
A sign of Botrytis Blight is smooth gray lesions that develop on the head of the affected flowers; the bud typically hangs over from the point where you see a lesion. You will also notice that new buds are being destroyed before they have the chance to bloom.
Cut and dispose of any blossoms that you notice are infected by this disease as soon as possible. Removing the diseased blossoms will help keep the disease from spreading to new areas. You may help prevent this disease with a weekly fungicide application. If you believe that your Rose may be affected by Botrytis Blight, take a look at our Rose diseases photos to see if your Rose looks similar.
This deadly Rose disease can kill an entire stem if not discovered and treated immediately. Brown Canker, which is caused by the fungus Cryptosporella Umbrina, is often found in outdoor Roses but can occur in greenhouses as well.
The main sign of this disease is red to purple spots on new growth that eventually develop into gray-white lesions. These spots will occur on the stem surface and cut off the plant’s pathway to nutrition. Negative effects are typically not noticed for a few years, until the canker become large enough to do some damage.
Make sure to check new plants for Brown Canker before introducing them into your garden. Cut back affected growth a few inches before you see the cankers appearing. You may want to dip your shears into a 1:10 bleach solution before cutting, because the open wounds are most susceptible. Look at our pictures of Brown Canker in our Rose diseases photos to see if your plant may be infected.
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