The disease is caused by a soil inhabiting bacteria that enters the plant through the wounds. The bacterium forms cream, brownish black in colour, irregular shaped, bulbous masses of tissue (galls) that starts as small tissue swellings and eventually develops into lumpy and rough textured masses (galls). This bacterium attacks the roots, bud union and is concentrated on lower base of a plant. Infected plants can survive with this gall for several years or decline and eventually die. These galls can negatively impact on rose’s production.
Galls start as small swellings and gradually grow into rough and bulbous masses of tissue.
Heavy infestations severely retard growth and new shoot formation.