Orthopelma

Systematic position: Orthopelma belongs to the order Hymenoptera and the family Ichneumonidae. Unlike many other members of this family, which are generalist parasitoids, this genus is specialized in parasitizing gall wasps (Cynipidae), particularly those that induce galls on rose bushes (the Rosa genus).

Affected crops: The primary hosts are various species of wild and cultivated roses. Orthopelma mediator, for example, is a well-known specialist parasitoid of the rose gall wasp Diplolepis rosae. This wasp creates distinctive, mossy galls often referred to as "bedeguars" or "rose apples" on the stems and leaves of the plants.

Biology and life cycle: The life cycle is inextricably linked to the host gall wasp. The adult female lays an egg inside the gall where the host larva is developing. The Orthopelma larva acts as an endoparasitoid, consuming the host larva from within. Usually, there is one generation per year, and the insect overwinter in the larval or pupal stage inside the gall cavity.

Damage patterns: While Orthopelma is a parasite of the gall wasp, the presence of these galls indicates a significant infestation of the rose plant. Galls cause structural deformation, interfere with nutrient transport within the shoots, and severely reduce the aesthetic appeal of the roses, often leading to secondary infections or weakened plant vigor.

Protection measures: The most effective method for controlling this issue is integrated pest management focusing on physical removal. Gardeners should regularly inspect rose bushes and prune off any stems showing signs of gall formation before the adult insects emerge in the spring. Destroying the infested plant material prevents the completion of the life cycle.

• Regular monitoring of rose bushes for mossy gall formations.
• Manual removal and destruction of galls during late winter or early spring.
• Improving plant health to prevent susceptibility to gall wasp colonization.