S.S. AWADALLA; M . E . RAGAB AND H.M. FATHY
Plant Protection Dept., Faculty of Agric., Mansoura University, Egypt .

ABSTRACT

The insects inhabiting sugar beet plants at Mansoura district included 18 injurious and 10 predatory species. Aphids. Cassida viuara (Vill.) Spodoptera lirroralis (Boisd.) Scoroobipalpa ocelLatella Boyed. and Pegomyia mixta Vill were the main insects infesting suger beet plants as indicated by their catch numbers . Coccinellids were the most abundant predatory species Numbers, ratios and population peaks of these insects were recorded. Prey / predator ratio between injurious and predatory insects reached 4.7- 4.8 during March, while the ratio reached a minimum of 1.1 aphids /1 predator in April. The differences between average population densities of aphids and that of their predators were insignificant but a postive correlation (r) between aphids and aphidophagous predators was recorded during the two growing seasons 1989/90 and 1990/91

Key Words: Suger beet, Insect pests, predators, Interaction,