Question
What is the cause of black spot, I have a climbing rose that suffers badley from blackspot every year, even though i spray, I get severe foliage lose and bud distortion, can i prevent this problem from occuring, rather than treating it once my roses have it.

Any advise would be most grateful.

kind regards
dave rowley

Answer


Black spot can not always be completely prevented, but with proper care it can be kept to a minimum and to a level that will not be detrimental to your roses.  Follow these steps:

Plant resistant varieties when possible.
When planting, space far enough apart to provide good air circulation around the plants.
Maintain a healthy plant through proper fertilization and watering.
Keep the leaves dry.  Avoid watering from overhead, instead water just the soil around the plants.
Water early in the day so the sun will dry foliage quickly.
Remove and destroy all infected plant parts.
Select a fungicide labeled for black spot on roses and apply according to the label.  ( preventative spraying normally begins in May or June or if symptoms are noticed.) Spray every ten 14 days with a fungicide.
If you would like to minimize your use of chemical pesticides, you can try spraying your roses with the following baking soda solution weekly.  Mix one tablespoon of baking soda with a gallon of water and a few drops of a lightweight horticultural oil.  This solution works best as a preventative, rather than as a cure.