Abstract
Cereal aphids are known as serious pests that cause considerable yield losses of wheat production. In this study, cereal aphids and their common natural enemies inhabiting the commercial wheat crop were investigated between February and April 2013 as a preliminary study in the Hail region, northern Saudi Arabia. Results showed that wheat crops were infested by four aphid species including the Russian wheat aphid Diuraphis noxia Kurdjumov, the English grain aphid Sitobion avenae Fabricius, the bird cherry-oat aphid Rhopalosiphum padi L. and the greenbug aphid Schizaphis graminum Rondani (Homoptera: Aphididae). The Russian wheat aphid D. noxia, however, was the most abundant species compared to other aphid species, totaling 343 individuals which represented 39.80% of all cereal aphids. The results showed a diverse community of specialist natural enemies that were associated aphids including parasitoid wasps as a complex and one Braconid species Aphidius matricariae Haliday (Hymenoptera: Braconidae), three coccinellid species (Adonia variegate Goeze, Coccinella quinquepunctata L. and Coccinella septimpunctata L.) (Coleoptera: Coccinellidae), one species of lacewing Chrysopa sp. (adults & larvae) (Neuroptera: Chrysopidae) and one species of hoverfly Eristalinus aeneus Scop. (adults and larvae) (Diptera: Syrphidae). This study, also, recorded a high abundance of polyphagous predators that included two species of ground beetles involving the black beetle Calosoma olivieri Dejean and Calosoma imbricatum Klug (Coleoptera: Carabidae), and spiders (Araneae) as generalist natural enemies of cereal aphids. In this article, population dynamics of captured cereal aphids and their common natural enemies, and their correlations will be described and discussed.