How to Identify Diseases on Rose Bushes

Rose bushes are vulnerable to bacterial and fungal diseases. Excess humidity and moisture promotes diseases in rose bushes. Prevention of diseases includes exposing the bush to plenty of sunshine, sanitizing gardening tools before cutting on the plant, and avoiding rough treatment, which might injure the rose plant's canes. It is also important to inspect your rose bushes on a regular basis, to identify and treat any potential problems. One sick plant can easily infect another nearby rose bush. Typical rose diseases include canker, powdery mildew, rose blackspot, rust, spot anthracnose and crown gall.

Look for dark or dead spots on the cane of the rose bush. This might be canker, typically caused by fungi entering the plant through a cut or wound. It might occur where a thorn has been ripped from the plant, at a graft union, or where you've left dead stubs by pruning too far above the bud eyes.

Inspect the leaves, looking for spots or discoloration.

Note the color of the spots. White powdering spots might be powdery mildew. Black spots with yellowed leaves might be rose blackspot. Reddish rough spots on the underside of the leaves might be rust. White spots with red rims might be spot anthracnose.

Check the leaves and buds, to see it they are misshaped. Dry curling leaves and shriveling buds, that don't open, are other signs of powdery mildew.

Look along the soil line of the rose bush. A sign of crown gall includes growths along the lower part of the plant, near the soil line.