There is more than once ailment that can beset a rose and each one is considered a fungal infection. Mildew, Rose Rust and Black Spot are common fungal infections that can easily be treated with fungicides.
Rose fungus, or fungal infections are rampant at the start of hot or humid weather and prevention is perhaps the most important part of care for roses. There are some precautions one can take to prevent rose fungus yet at times prevention is not possible and these instances rose fungus must be treated.
Precautions
Providing plenty of water is the first step in promoting healthy plants along with good air circulation and fertilizers. Keep roses pruned and avoid wetting their leaves as this can encourage disease. Pick off all old stems and leaves.
If other plants in your garden show signs of disease this may be spread to roses through insects. Insects on their own are carriers of disease. Once you have spotted fungus in your garden start treatment without haste.
Planting roses in sunny areas and providing lots of water will go a long way to preventing rose fungus taking hold.
Treating Rose fungus
A good quality fungicide is normally an effective rose fungus
treatment if done early. If the fungus is left to fester it can be hard to control and hard to eliminate. Rose fungus will weakened plants as the effort taken to fight against disease makes it harder for them to grow and produce flowers. Fungicides that contain sulphur are good for the control of fungus.
If you find fungus on your plants start with removing all dead leaves as this will provide a smaller area that the rose has to fight against disease. It can then concentrate on new growth.
Rose Powdery Mildew
Powdery mildew grows on the surface of any green areas such as leaves and stems. It can only survive on healthy plants as it demands nutrients and feeds off the host plant. At the first sign of mildew treat your roses with a fungicide according to the directions.
Young leaves will start to curl up and die and may not grow to their full size.
Rose Black Spot
Black spot is a common disease among causes caused by a fungus called diplocarpon rosae. It is distinguished by black spots on the under side of the leaf. Around these black spots the leaf will turn yellow and ever fall off and if left untreated every single leaf will drop off. The rose will become very weak and will most likely die.
It is important to remove each diseased leaf off the ground and burn it. Do not put them into the mulch pile. Treating black spot should be done in Spring with the aid of a fungicide that is specifically formulated. The treatment should continue through the growing season until the first frost.
Rose Rust or Rusty Spots
Rose Rust is caused by a fungus from the Phragmidium family. Fungus rust is able to survive winter on a host plant and infect the plant in spring. Rose Rust spores are air borne and are spread by the wind.
Rose Rust first shows on the underside of the leaf and creates bright orange pustules. As it spreads and develops the top of the leaf begins producing yellowish to orange spots.
It is as important to remove all fallen and infected leaves from your garden completely. Treatment is needed for the entire rose bush with a specially formulated fungicide.
Botrytis Blight
This type of fungus mainly affects flower buds which deceay and then die. It is greyish to black in color and grows just below the head of the bloom. In order to prevent this fungus from spreading it is necessary to remove the blooms.
Brown Canker Fungus
This fungus has the ability to attach to any part of the rose bush that is above ground. It has the power to kill a rose plant if not treated. Brown Canker produces purple or red lesions on new rose stems and in older rose stems These lesions are grayish white.
Fungicides that are specially formulated for Brown Canker Fungus work well, but should be administratively strict according to directions.
It is also feasible to treat roses with homemade solutions such as a mixture of water and baking soda or dish washing liquid diluted in water. Place in a spray bottle and spray the infected areas well. Repeat this process until you see results.