SEASONAL ABUNDANCE OF APHIDS AND THEIR NATURAL ENEMIES IN WHEAT FIELDS IN UPPER EGYPT .

A.H.EL-HENEIDY
Biological Control Dept., Plant Protection Research Institute, ARC
Dokki, Giza , Egypt

ABSTRACT

Seasonal abundance of certain biocontrol agents associated with aphids in wheat fields was studied for the two seasons 1988/89 and 1989,90 in two districts of each of Assiut and Sohag Governorates in Upper Egypt. Four species of aphids were recorded infesting wheat plants during the study. The highest rates of aphid infestation were observed during March. Six groups of predators were counted weekly. Highest numbers of predators were recorded during April. Coccinellids were the most abundant predatoiy species in wheat fields. Highest parasitism % was estimated in early April and late of February in 1988/89 and 1989,90 seasons, respectively in the two Govemorates. Four hymenopterous parasitoid species were identified parasitizing aphids in wheat fields.

Key Words: Aphids, Predators, Parasitoids, Wheat , Egypt .