Rose scale

The rose scale (Aulacaspis rosarum) is a small sap-sucking insect belonging to the Diaspididae family. It is a significant pest primarily affecting plants within the Rosaceae family, causing long-term damage to ornamental roses and various wild species.

This pest targets the woody parts of the plants, specifically stems and branches. While they are often found on roses, they can also infest blackberry and raspberry plants if the environmental conditions are suitable for their proliferation and survival.

The biology of Aulacaspis rosarum involves overwintering as fertilized females on the bark of host plants. Once temperatures rise in spring, the females lay eggs under their protective, scale-like coverings. The newly hatched nymphs, known as crawlers, actively move to find suitable feeding sites before settling down to develop their own protective scales.

Damage is characterized by the presence of white or grayish scale clusters on the stems. Constant feeding by these insects results in reduced vigor, stunted shoot growth, and necrosis of the bark. In severe infestations, the cumulative damage can lead to the death of the entire plant or significant portions of the stem system.

Effective management requires a multi-stage approach. During the dormant season, pruning out heavily infested wood is essential. During the active growing season, applying horticultural oils or targeted systemic insecticides during the crawler stage is the most effective way to suppress population growth.

• Cultural control: pruning and sanitation of infected stems.
• Biological monitoring: identifying crawlers during the spring season.
• Chemical control: applying insecticides specifically timed to nymph emergence.