ECOLOGICAL AND MORPHOLOGICAL STUDIES ON THE WHITE PEACH SCALE PSEUDAULACASPIS PENTAGONA (TARGIONI - TOZZETTI) AND ITS NATURAL ENEMIES

Abstract

This study included: world and local literature surveys, distribution and host plants of the white peach scale, Pseudaulacaspis pentagona (Targioni - Tozzetti) in Egypt, description of male, nymphal instars, poulation dynamics and natural enemies (at three locations over two years), determination of generations, effect of cardinal direction on the level of infestation and the effect of ecological factors on the population density. 1- Morphlogical studies:

The investigated material of the species P. pentagona belongs to the true scale insects or the so-called " armoured scales", i.e., family Diaspididae. This choise is based upon the wide distribution and the economic status of this species. The use of immatures as promissing tools in coccid taxonomy is

now regarded as a common concept among cocoidologists. Therefore • additional information in this direction was the principal motive of the present work. Full-illustrated descriptions are given for all the immature

forms. The work extended to present the adult male.

Changes in the covering scale were traced throughout the course of development for nymphal stage of the species. The idea was to correlate between the appearance of the scale and the form of insect beneath. Scales are presented in verbal descriptions. Results were, in general, indicative. The developmental pattern of the species become obvious through the disappearance or degeneration of certain characters, and appearance or increase in others sexual dimorphism became recognizable after the first moult, i.e., in the second nymphal instar. Only one symptom of such dimorphism did occure • during the first nymphal instar.