Diversity and distribution of predatory assemblages in a non-treated citrus orchard in central Mitidja (Blidean Atlas, Algeria)

Abstract: Valorization of auxiliary complexes depending on citrus production pests is of important interest for biological pest management in Algerian orchards. The goal of this study was to explore how native predator populations prevail in a citrus orchard without phytosanitary and crop management. The monitoring included sampling and observing predator guild populations at the periphery and center of the orchard, and upper and lower canopy levels, during winter and spring-autumn periods. The orchard richness included 34 taxa divided into 8 orders and 18 families of predatory arthropods, Neuroptera, Coleoptera, Diptera, Heteroptera, Hymenoptera, Dermaptera, Mantoptera and Araneae. The Coccinellidae belonging to scale species regulators as well as the Araneae and Chrysoperla carnea were the most represented. Predatory communities are not homogeneous, spreading differently in the orchard depending on season and habitat. They remain at the periphery of the orchard in winter and then move towards the center in spring. They also move differently from one canopy level to another. Their periods of activity, especially those of ladybirds, change monthly, and their regulation on the tree could be hampered by the presence of spiders.