ON THE NATURAL ENEMIES OF THE MAJOR PESTS INFESTING COTTON IN EGYPT

Population densities of the six predators Coccinella undecimpunc­tata, Chrysopa carnea, Onus albidipennis, paederus alfierii, Scymnus sp. and true spiders prevailing in contton fields were studied in Fayoum Gov­ernorate from May until September, 1988. The study was carried out weekly in 5 plots treated with different insecticides and in a control plot. The poputlation densitiy of the predators was high in july then decreased gradually until the end of the season. Due to insecticide treatments the numbers of predators / 100 hills in treated plots were always lower com­pared with those in the control plots. Two species of parasites were found attacking the cotton leafworm spodoptera littoralis ; the egg - lar­val parasite, Chelonus inanitus and the larval parasite, Microplitis rufiven­tris. In addition, three other species of parasites were found parasitising on the pink bollworm Pectinophora gossypiella .These were Bracon brevi­cornis, Exirestes roborator and Apanteles sp. The cotton ophid Aphis gos­sipii was observed during May , August and September without parasites parasitizing upon it.