Laboratory and field experiments were carried out at Mansoura
district to survey the primary parasitoids associated with five aphid species
namely, Aphis craccivora Koch, Brevicoryne brassica(L.), Sitobion avenae
(Fabricjus), Rhopalosiphum maidis (Fitch) and R.padi (L.). These species
infested the host plants ,broad bean, cowpea, cabbage, wheat and corn
during the two seasons of 1998 and 1999. The results indicated that five
aphid parasitoids were recorded. Among them, Diaeretial/a rapae (M'lntosh)
was the most common parasitoid which emerged from the four aphid species,
Aphis craccivora, Brevicoryne brassica, Sitobion avenae and R.padi. There
are no previous records for Diaeretial/a rapae as a parasitoid of Acraccivora
in Egypt. Therefore, the present study represents the first record of this
species as an important parasitoid of Acraccivora. The population density of
this aphid species and its parasitoids as well as the percentages of parasitism
on broad bean and cowpea were studied.The peaks of mummified aphids on
broad bean were recorded during January and March, while it were recorded
on cowpea in September and August, in 1998 and 1999, respectively. The
results also indicated the effective role of these parasitoids in controlling the
infestations of Acraccivora on both broad bean and cowpea in the field.