Rose stem sawfly

The Rose stem sawfly (Cladardis elongatula) is a member of the order Hymenoptera and the family Tenthredinidae. It is a common pest that specifically targets rose bushes, causing significant damage by nesting within the stems during its larval stage.

This pest is primarily specialized on roses (genus Rosa). The larvae bore into the stems, creating tunnels that disrupt the plant's vascular system, which hinders the transportation of nutrients and water to the growing tips of the branches.

The life cycle begins with the adults emerging in spring to lay eggs under the epidermis of young, soft shoots. Upon hatching, the larvae immediately begin tunneling downward inside the stem, which protects them from environmental factors and surface-applied treatments.

The primary symptom of an infestation is the drooping, wilting, and subsequent blackening of the shoot tips. Once the larva has finished its development, the damaged portion of the stem usually breaks off, leading to stunted growth and reduced blooming potential of the rose bush.

To control and prevent infestations, gardeners should follow these practices:

• Regular monitoring of rose bushes during the early spring growth period.
• Immediate pruning of affected shoots at least 5-10 cm below the visible damage point to remove the larvae.
• Burning or deep burial of the pruned material to ensure the destruction of the larvae.
• Application of systemic insecticides or botanical oils during the adult emergence phase to deter egg-laying.