Rose stem sawfly

Systematic position: Syrista parressyi belongs to the order Hymenoptera, family Cephidae. It is a specialized pest known to target rose bushes, causing internal structural damage that disrupts the physiological development of the plant stems.

Host plants: The primary host plants for this species are various cultivars of ornamental roses and wild rose species (Rosa). The pest thrives in rose gardens and nurseries, potentially causing widespread damage if left unmanaged during the peak growing season.

Biology and life cycle: The adult sawfly emerges in spring when new rose shoots are rapidly growing. The female uses her ovipositor to insert eggs into the soft tissue of young stems. Upon hatching, the larvae immediately bore into the pith, creating internal galleries that sustain their development while protecting them from external environmental factors.

Nature of damage and harm: The presence of the pest is indicated by the wilting and subsequent browning of terminal shoots. Because the larvae feed on the core of the stem, the transport of water and nutrients to the upper parts of the plant is blocked. This results in dieback, stunted growth, and a significant reduction in flower production, compromising the aesthetic value of the garden.

Control measures: Managing Syrista parressyi requires early intervention.

• Sanitary pruning: cut off and burn infested stems well below the damaged area.
• Chemical control: apply systemic insecticides during the peak flight period to kill adults before they lay eggs.
• Biological monitoring: use sticky traps to track the population density in spring.