Rose diseases

From Gardening Wiki

Contents 1 Rose Diseases 2 Rose Powdery Mildew 3 Black Spot Roses 4 Leaf Scorch of Roses 5 Rose Rust 6 Rose Canker

Rose Diseases

Rose Powdery Mildew

Mildew causes a powdery effect upon leaves. It is especially prevalent upon the Crimson Ramblers and Moss Roses. It appears when the nights are cool and days are hot and sultry, and disfigures the plant, but does not affect the next year's crop of flowers. Sulphur powdered upon the leaves is a suggested control.

Black Spot Roses

Black Spot is the most serious disease, and is especially bad on the American Beauty and other hybrid perpetuals. It is confined to the foliage and appears in Midsummer. It looks like a black or purple spot one-quarter inch in diameter,; the blotches are more evident on the upper surface. When the patches are examined they will be found to have a fine mycelium growing on them which causes premature defoliation. If possible the infected leaves should always be removed. Spray with Rordeaux mixture (3-5-50), or other copper fungicides; potassium sulphide does not seem as good.

Leaf Scorch of Roses

Leaf Scorch, when severe, causes the infected areas of the leaf to drop out. The canes are also attacked. The wild Roses, too, are in- fested. The best control is to use copper fungicides.

Rose Rust

Rose Rust is especially prevalent on hardy varieties. It has Summer spores and Winter spores and attacks canes as well as leaves. The best, preventive is the removal and burning of all rusted canes. A spray with some copper solution to protect and prevent is all that can be advised.

Rose Canker

Rose Canker appears as a warty growth on the canes; excrescences on wood. It can only be cut out when found. It is caused by a fungus.