The present study aimed to evaluate the population levels and interactions between cereal aphids (Schizaphis graminum and Sitobion avenae) and their natural coccinellid predators in a winter wheat crop. Weekly observations were conducted from 10 April to 22 May in six 1 m² sampling plots, three located at the field margins and three within the interior. Aphids and coccinellids were collected using a sweep net, and all individuals were counted and identified in the laboratory. Population densities (individuals/m²) and the rate of aphid decline between successive sampling dates were calculated, together with the estimated predation potential of coccinellids based on a feeding rate of 400 aphids per adult per week. Results showed a rapid increase in aphid populations until early May, followed by a gradual decrease correlated with the rise in coccinellid abundance. Mean aphid densities ranged from 350 to 590 individuals/m², while coccinellid densities varied between 4 and 7 individuals/m². The aphid-to-coccinellid ratio ranged from 58 to 109 aphids per predator, depending on location. Estimated weekly aphid consumption reached up to 2,500 individuals/m², indicating that coccinellids exerted a measurable regulatory pressure on aphid populations. The study demonstrates the importance of natural predation in the biological control of cereal aphids and highlights the potential of coccinellids as effective biocontrol agents in wheat agroecosystems. Encouraging ecological farming practices that conserve predator populations can significantly enhance the sustainability of integrated pest management programs in cereals

Cereal aphids, Schizaphis graminum, Sitobion avenae, Coccinellidae, biological control, wheat agroecosystem, predator-prey dynamics, population density

agronomy

Presentation: poster