الفهرس 
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Abstract
1.1. Hosts and Distribution of genu.s Aphytis in Egypt:Samples of Aphytis species collected were associated with armored scale insects on 20 host plants in \9 governorates in Egypt.The present work showed that A_ Iingnanensts to be the most effectivespecies of genus Aphyti«, followed by A_diaspidis and A. mytilaspidis. Alingnanensls was collected from 11 species of armored scale insects on 6 plant hosts distributed over 4 governorates; A. diaspidis was collected from 6 species of armored scale insects fuund on 6 plant hosts distributed over 7 governorates and A. mytilaspidis was collected from 6 species of armored scale insects on 5 plant hosts found in 5 governorates, governorate. The remaining Aphytis species were each associated with one species of armored scale insect on 1 to 2 plant hosts, in 1 to 2 governorates. A. chilensls is associated with 4 species of armored scale insects on 5 host plants found in 5 governorates, A_ africanus, A. aonidlae, A_hfsp<micll~’ and A, meltnus arc associated with 2 to 3 species of armored scale insects each. A, ofricanus and its host insects were collected from 5 host plant species in 5 governoratcs. A. aonidlae and its host insects were found on 3 plant hosts distributed over 3 governorates. A. hispanicus and its host insects were collected from 4 host plant species in 4 governorates and A, melinus and its host insects were found on 2 plant hosts in only 1.1.2. Taxonomy: In the present work, ~Especies of the genus Aphytis Howard were collected, identified, described, ami illustrated. These species arc: Aphytis africanwi Quednau’”, Aphytis aonidiae (Mercer)”, Aphytts chilensis Howard” , Aphyti« chrysomphali (Mercer), Aphyti,~ coheni DeBach., Aphy’i.~’ diaspidls (Howard), Aphyti1s hispanicus (Mt:rcel), Aphytis holoxanthus Dcbach”, Aphyti» lepidosaphes Compere, Aphytis libanicus Traboulsi”, Aphytis lin;.;nul’/en<:is Compere, Aphyus melinus DeHach, Aphytis mytilaspidis (LeRaron), Aphytis apuntiae (Mercer)”, Aphytis paramaculicornis DeBach & Rosen”, Aphytis philippinensis DeBach & RO~Il”’, Aphytis phoenicis Dcbach & Rosen” and Aphylis vandenboshi Defsach &Rosen”, Ten of these Spel; ies are recorded in thi s work for the first rime in Egypt, and are marked in the forernentioned list with an asterisk (”’). The most important characteristics of the genus Aphyt/s Howard are summarized in the following: Number of setae on mesoscutum; setae of submarginal vein and parapsis; presence or absence of overlapping crenulac; length of prnpodeum; variation in the relative lengths of propodeum, scutellum, and rnetanotum ;nurnbcI of sensilla on club; length of ovipositor and sheath and the variation in the relative lengths of the midtibia and basitarsus. A key is provided rUT the identification and differentiation 01’ Egyptian Aphyli:> species based Oil the characteristics ofthe adult female, 2. Popu lation dynamics of the genu!j Aphytis Howard in Egypt: The population dynamics of 18 species of the genus Aphytis in Egypt were observed on ten host plunts infested by eleven armored scale insect species in seven governorates between 1997 and ::WOO. 2.1. Aphyfis afrjcanus a.••s.oflillted with AvniJieJla aurantii on CitrIC> sp. in Qalyuhiya: The results indicated that this species had two pew occurring in January and November of the first year (1’997).ln the second year (l99RThe potential biocontrol agents have been applied separately for the first time to infested soil with the plant pathogens in pot studies under greenhouse condition. Dox liquid culture preparation of T. harnanum or the preparations of the other tested biocontrol were coated separately to the seeds of susceptible cultivar of soybean (cv. Crowford) as well as susceptible cultivar of sunflower (cv. Miak). When these coated seeds were infested in the soil (under greenhouse condition), which was incorporated with the appropriate inoculum of the tested target pathogen(s) via simultaneous applications of both of the biocontrol and the target pathogen, it led to reduced diseases severity. This is the first study to demonstrate the effectiveness of all the three adverse group of micro-organisms tested as a biocontrol agents against M phaseolina and F. solani Esp. phaseoli in both soybean and sunflower under greenhouse condition. The three diverse group of micro-organisms which were used as a biocontrol agents were antagonistic to the pathogenic fungi of the two plants (soybean cv. Crowford and sunflower cv. Miak). Preliminary screening of activities towards the tested pathogens in vitro (petri dishes) trials revealed inhibition to both microsclerotia production and growth of M phaseolina as well as the growth of F. solani Esp. phaseoli. More importantly the isolate (No 112) was demonstrated to be highly effective ”efficient” among the biocontrol agents used in this study, i.e., B. subtilis, and the other fungal tested antagonist (T. harzianum) in controlling the diseases caused by the two phytopathogenic fungi M. phaseolina and F. solani tsp. phaseoli in the target plants of this work The germination and radical root growth assay for the phytotoxicity of the culture filtrates (CFs) of the three different biocontrol agents were employed on both the soybean and sunflower seeds. Serial concentrations of these CFs were used. A visible damage on both the soybean and the sunflower radicals was demonstrated. This was based on the length measurements of radicals (Root-inhibiting activity) in the CFs treated seeds as compared with the water controls. This points to the contribution of a phytotoxic substance which.