Witches’ broom like appearance and small twisted leaves are characteristic symptoms of rose rosette disease. Eriophyid mite species Phyllocoptes fructiphilus Keifer, the vector for rose rosette disease is a tiny mite and cannot be seen without magnification.
These symptoms can be confused with herbicide injury. Thus, other symptoms and necessary for confirmation.
Rapid growth from certain sections of the stem, dying branches, thorn proliferation, unusual reddening of leaves that doesn’t change with age are major symptoms of rose rosette disease.
Severe thorn proliferation is characteristic to rose rosette disease. Feeding by the mite Phyllocoptes fructiphilus results in transfer of the virus to healthy roses. Mites prefer to feed on tender new growth, and the virus modifies plant development. The mites are typically found in the apex of rose shoots where they feed and reproduce.
Healthy plant (No thorn proliferation) - This is normal.
Unusual leaf shape on plants with rose rosette disease.
Distorted flower bud; leaf developing from flower bud tissue.
Branch proliferation and distorted leaves. Rapid elongation of branches is another characteristic symptom (not shown here).
Severe yellowing and stunting of the plant. Infected plants usually die in 1-2 years.