Pests of Oilseed Rape and Parasitoids of the Cabbage Aphid Brevicoryne brassicae L. In Eastern Algeria

This study presents the first comprehensive survey of insect pests associated with oilseed rape (Brassica napus, InVigor variety) in the Guelma region, Eastern Algeria, with a focus on the parasitism of the cabbage aphid (Brevicoryne brassicae). Sampling was conducted over a 6-hectare plot using yellow traps (pre-flowering), beating (full bloom), and direct sampling (post-flowering). The pest community included Brassicogethes aeneus, Psylliodes chrysocephala, Ceutorhynchus spp., Tropinota spp., Rhopalosiphum padi, Myzus persicae, and B. brassicae. Parasitism of B. brassicae during fruit maturation revealed two dominant primary parasitoids: Diaeretiella rapae and Lysiphlebus testaceipes, with parasitism rates peaking at 31.76%. However, hyperparasitoids (Pachyneuron aphidis, Asaphes vulgaris, Syrphophagus sp.) were also recorded, potentially limiting the effectiveness of biological control. These findings provide valuable insights into trophic interactions and contribute to the development of sustainable integrated pest management (IPM) strategies for oilseed rape production in Algeria.