Scale insects ( Hemiptera : Coccoidea ) infesting apple , apricot , pear trees and their abundant parasitoids in Egypt

Scale insects are the major pests infesting apple, apricot and pear trees in Egypt. The aim of the present work is to study a survey of scale insects infesting apple, apricot, pear trees and their abundant parasitoids in Egypt. A survey of scale insects infested apple, apricot, pear trees and their abundant parasitoids were carried out all over Egypt during 2009-2011. The results indicated that apple, apricot and pear trees were infested by 19, 10 and 10 scale insect species and associated with 12,6 and 8 parasitoid species, respectively.


INTRODUCTION
Scale insects are the major pests infesting apple, apricot and pear orchards in Egypt.Abd-Rabou (2003) and Bakr et al. (2009) reviewed the scale insects infested different crops in Egypt.Scale insects feed on plant sap.Scale feeding slowly reduces plant vigor, heavily infested plants grow poorly and suffer dieback of twigs and branches.An infested host is occasionally so weakened that it dies.Scales often secrete a sticky honeydew which supports the growth of black sooty molds.
The aim of the present work is to study a survey of scale insects infesting apple, apricot.pear and their abundant parasitoids in Egypt.

MATERIALS AND METHODS
A survey on scale insects infested apple, apricot, pear trees and their abundant parasitoids were carried out all over Egypt during 2009-2011.Infested plants with scale insects were examined in the field, using a pocket lens.Leaves, stems and twigs were collected and placed separately in paper bags for further examination in the laboratory.Identification of scale insects was made by examining its adult in Canada Balsam, according to Abd-Rabou (2001).Thereafter, the leaves and twigs were kept in a closed paper bags and transferred to the laboratory for further examination and counting.Each leave was stored in a well-ventilated emergence glass tube and monitored daily for parasitoid emergence.Eleven armored scale insect species attacking 62 host plant species including apple, apricot and pear (Hammad and Moussa, 1973).The host of P. oleae was apple (El-Minshawy et al., 1974).R. pustulans attacked apple trees in Egypt (Mangoud, 1994).Abd-Rabou (1997b) recorded that the parasitoid, Aphytis chrysomphali (Mercet) associated with five armored scale insects in different locations in Egypt.Aphytis diaspidis (Howard) was recorded for the first time in Egypt by Priesner & Hosny (1940).Hafez (1988) recorded Aphytis lingnanensis Comepre as the most common species of A. aurantii on Citrus sp.Priesner & Hosny (1940) recorded Aphytis mytilaspidis (Le Baron) for the first time in Egypt from all over the Nile Delta.Aphytis sinaii Abd-Rabou was collected in a few numbers by Abd-Rabou (2004).Encarsia citrina (Craw) was recorded for the first time in Egypt by Priesner & Hosny (1940).Abd-Rabou (1997a) mentioned that E. citrina should be considered a promising candidate for utilization in biological control of armored scale insects in Egypt.This species was reared from 8 species of diaspidid scale insects and maximum parasitism rates ranged between 23 and 65%.Pteroptrix aegyptica (Evans & Abd-Rabou) was recorded for the first time in Egypt by Evans and Abd-Rabou (2005).Habrolepis aspidioti (Compere & Annecke) was recorded for the first time in Egypt by Priesner and Hosny (1940).This species reported as an effective parasitoid on different armored scale insects in different locations in Egypt (Abd-Rabou,1997c).Blepyrus insularis (Cameron) was recorded for the first time in Egypt by Awadallah et al.(1999).Leptomastidea abnormis (Girault) was recorded for the first time in Egypt by Abd-Rabou and its reared from M. hirsutus with maximum parasitism rate was 21% (Abd-Rabou, 2000).Leptomastix dactylopii Howard was recorded for the first time in Egypt and its was reared from M. hirsutus with maximum parasitism rate was 8% (Abd-Rabou, 2000).Coccophagus scutellaris (Dalman) collected for the first time in Egypt by Priesner and Hosny (1940).Metaphycus lounsburyi (Howard) was recorded for the first time in Egypt by Abd-Rabou(1998).Microterys flavus (Howard) was recorded for the first time in Egypt and the rate of parasitism of this species on C. floridensis, averaged 0.8 and 2.4% during the two years under considerations, respectively.Maximum parasitism rates reached 3.4 and 8.0% during Mid Nov. and early Nov., respectively (Abd-Rabou, 2001b).M. flavus was mass reared and released at monthly intervals in olive groves infested with S. oleae at three localities in Egypt and percentages of parasitism increased after releasing from 11 to 35% (Abd-Rabou, 2004).

Table 1 :
Table (1) the apple trees were infested by 19 scale insect species: 11species belonging to Family Diaspididae, three species belonging to family Pseudococcidae, three species belonging to family Margarodidae and one species of families Asterlecaniidae and Coccidae.During the present work 12 parasitoid species recorded associated with aforementioned scale insects .Table (2) showed that apricot trees infested by 10 scale insect species: 7 species belonging to Family Diaspididae and one species of families Asterlecaniidae, Coccidae and Pseudococcidae.The present work 6 parasitoid species recorded associated with aforementioned scale insects.List of scale insects infesting apple trees and their abundant parasitoids in Egypt

Table 2 :
List of scale insects infesting apricot trees and their abundant parasitoids in Egypt ) showed that pear trees infested by 10 scale insect species: 8 species belonging to Family Diaspididae and one species of Families Coccidae and Pseudococcidae.Also during the present work 8 parasitoid species recorded associated with aforementioned scale insects.

Table 3 :
List of scale insects infesting pear trees and their abundant parasitoids in Egypt