Scale insects are one of the most important pests of orchard trees in Egypt. The present review includes the Egyptian literatures of biological studies conducted on scale insects.

The population dynamics of the green shield scale, Pulvinaria psidii (Mask.) (Hemiptera -Coccidae) was studied for two successive years (2008)(2009) on guava trees at Shibin El-Qanater district, Qalubiya Governorate. The obtained results revealed that, P. psidii occurred on guava trees all the year round and has two overlapping generations a year. The 1 st generation started from early March to early August/mid-August, peaked in mid-May (early summer) with duration of 5.0 -5.5 months at field conditions of 20.7 -21.3°C and 70.7 -71.9%R.H. The 2 nd generation occurred from early May to mid-November, peaked in mid-August (late summer) with duration of 6.0 -6.5 months at 24.2 -25.0°C and 69.4 -70.4%R.H., respectively. The favorable time for abundance of P. psidii occurred in early and late summer during both high temperature and relative humidity. The adult population was relatively higher than nymphal population one in winter months and this may be due to the cold weather and most of the nymphs attained to the adult stage which sheltered on stems bark or in the stem cracks.Daily mean temperature and %R.H. were effective on both nymph and adult populations in 1 st and 2 nd generations in the two studied years, the population was correlated with the increase of temperature. The combined effect of the daily mean temperature and %R.H. on both nymph and adult populations was high on the both generations. The changes in the half monthly counts of nymph and adult populations referred to the effect of the tested weather factors on the 1 st generation ranged 83.8 -87. 3% & 55.8 -75.9% and 55.7 -69.1% & 51.4 -56.6% for the 2 nd generation in the two studied years, respectively.Pulvinaria psidii (Mask.

The seasonal activity of fiorinia date scale, Fiorinia phoenicis Balachowsky, 1967 (Hemiptera -Diaspididae) was studied for two years (March, 2008 until mid-February, 2010 on date palm at Giza governorate. The obtained results revealed that F. phoenicis has three overlapping generations under field conditions. The 1 st generation (early summer generation) peaked in early June and the 2 nd generation (late summer generation) peaked around August/September whereas the 3 rd generation (autumn generation) peaked in October/November. The shortest generation was the late summer generation (2.5 -3.0 months) at 27.9 -28.6ºC and 63.5 -64.8%R.H.whereas the longest one was autumn generation (4.5 months) at 21.6 -22.0ºC and 65.9 -66.3 %R.H. The early summer generation had intermediate duration (4.0 -4.5 months) at 20.9 -21.2ºC and 62.5 -63.0%R.H in the two years, respectively. The population density was varied in the three generations, the autumn generation was the largest one with total population ranged 944.7 -1016.0 insects/leaflet with mean of 980.4 insects/leaflet followed by late summer generation 829.0 -1025.7 insects/leaflet with mean of 927.4 insects/leaflet whereas the smallest one was the early summer generation (422.4 -575.7 insects/leaflet with mean of 499.1 insects/leaflet). The insect population occurred on date palm fronds all the year round and decreased to lower numbers during winter season and this referred to the cold weather. The basal stratum of date palm leaflets received the highest infestation (37.4 -38.3%) than middle (34.4 -35.3%) and apical ones (26.4 -28.2%).On the other hand, the insect activity affected significantly with daily mean temperature and %R.H. in the both years. The combined effect of daily mean temperature and %R.H on nymph and adult populations showed 66.1 -69% & 48.1 -49.2% in the 1 st generation, 65.4 -74.0% & 63.8 -78.4% in the 2 nd generation and 60.9 -77.4% & 48.6 -63.5% in the 3 rd generation in the both years, respectively.

The journal of Toxicology and pest control is one of the series issued twice by the Egyptian Academic Journal of Biological Sciences, and is devoted to publication of original papers related to the interaction between insects and their environment. The goal of the journal is to advance the scientific understanding of mechanisms of toxicity. Emphasis will be placed on toxic effects observed at relevant exposures, which have direct impact on safety evaluation and risk assessment. The journal therefore welcomes papers on biology ranging from molecular and cell biology, biochemistry and physiology to ecology and environment, also systematics, microbiology, toxicology, hydrobiology, radiobiology and biotechnology. www.eajbs.eg.net Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.

he present work was conducted for one year (January -December, 2013) on six avocado cultivars cultivated in new reclaimed lands at Borg El Arab (Alexandria Governorate), El Bostan (Beheira Governorate), El Sadat (Menofiya Governorate) and Sarapium (Ismailiya Governorate). The study was conduct to survey the scale insect and mealybug species and their associated natural enemies as well as the degree of infestation on avocado trees. The obtained results revealed eight species of scale insects and Mealybugs. Two coccid species [Coccus hesperidum L. and Pulvinaria psidii (Mask.)], Four diaspidid species [Hemiberlesia lataniae (Sign.), Aulacaspis tubercularis (Newst)., Aonidiella aurantii (Mask.) and Aspidiotus nerii Bouche] and Two Pseudococcid species [Pseudococcus longispinus (Targ.-Tozz.) and Ferrisia virgata (Ckll.)]. Associated parasitoids were Coccophagus scutellaris on C. hesperidum, Aphytis lepidosaphes, Habrolepis aspidioti and Marietta leopardina on H. lataniae, Encarsia citrina and Habrolepis diaspidi on A. tubercularis and Anagyrus spp. on P. longispinus. Also, associated predators were Rodalia cardinalis on C. hesperidum and two coccinellid predators (Cryptolaemus montrouzieri and Scymnus syriacus) on P. longispinus. H. lataniae was the most abundant (56.8%) followed by F. virgata (42.5%) , A. tubercularis (39.8%) , P. longispinus (31.7 % ), C. hesperidum (26.6%), P. psidii (15%), A. aurantii (15%) and A. nerii (14.3%).Hass cultivar proved the highest infestation rate in the four localities followed by Boothy and Waldim cultivars. Fuerte, Gwen and Lula cultivars had the lowest infestation rate.