Mangoud, A.A.H. 2008 Manipulation of the two predators, Scymnus syriacus and Hyperaspis vingigurrae for augmentative release for controlling the virgatus mealybug, Ferrisia virgata.. Proceedings of the XI International Symposium on Scale Insect Studies, Oeiras, Portugal, 24-27 September 2007. ISA Press Lisbon, Portugal 322 pp.

Notes: The virgatus mealybug, Ferrisia virgata (Cockerell) (Coccoidea: Pseudococcidae) is an important pest on ornamental plants and fruit trees. During the present work, two predators were released in three plots in the two years 2004 and 2005. In the first year (2004), the infestation decreased gradually after the release Scymnus syriacus and the percent reduction increased only gradually (23, 40, 48 and 59% in the four months July, August, September and October, respectively). In the second plot, Hyperaspis vingiguerrae reduced the number of mealybugs, with the percent reduction also increasing gradually (22, 37, 44 and 52%) after the four months. In the third plot, the two predators were released together and the percent reduction of F. virgata increased rather faster - 39, 58, 67 and 80% in the four months. In the second year (2005), the infestation in the first plot decreased quite fast after the release of S. syriacus, with percent reductions of 43, 62, 71 and 80% during the four months (July, August, September and October, respectively). In the second plot with H. vingiguerrae, the reduction in the mealybug population was 37, 52, 67 and 74% respectively, while in the third plot, where the two predators were released together, the percent reduction of F. virgata was greatest - 58, 77, 85 and 94%, respectively.