Field Efficacy of Parasitoid, Coccophagus scutellaris (Hymenoptera: Aphelinidae) and the Predator, Exochomus flavipes (Coleoptera: Coccinellidae) against Pulvinaria Psidii (Hemiptera: Coccidae) in Egypt

The aim of this study was to investigate the biological control of the green shield scale, Pulvinaria psidii Maskell (Hemiptera: Coccidae), on guava trees in Gahrbiya, Egypt, by the release of two of its natural enemies. For this purpose, 12 releases of larval Exochomus flavipes (Thunberg) (Coleoptera: Coccinellidae) and Coccophagus scutellaris (Dalman) (Hymenoptera: Aphelinidae) were carried out on guava trees between May 2007 and April 2008. These two beneficials were reared under defined climatic conditions (25-27°C and 65-75%) in a laboratory. A significant reduction in the number of P. psidii populations was recorded as compared with control plots. Six months after the release of E. flavipes, the average populations of P. psidii decreased from 1897/30 to 475/30 leaves in the treated plot. With regard to C. scutellaris, the number of parasitized P. psidii nymphs in the treated plots increased from 2% to 54% as compared to the control plots. The present study indicated that C. scutellaris and E. flavipes are potential biocontrol agents of P. psidii on guava.