POPULATION DYNAMICS OF CHAFF SCALE, PARLATORIA PERGANDII COMSTOCK IN COMPARATIVE ANALYSIS OF FLUCTUATING POPULATION DENSITIES ON THREE CITRUS VARIETIES IN EL-BEHEIRA GOVERNORATE, EGYPT.

Investigation throughout the subsequent years of 2011-2012 and 2012-2013 indicated that chaff scale, P. pegandii is an important economic pest on citrus trees in Abou El-Matamer area, El-Beheira Governorate, Egypt. It has been recorded in relatively high rates all over the year on three citrus varieties called Succari, Baladi and Navel oranges. Field observation and recorded data revealed that the common abundance was recorded for chaff scale on Succari oranges followed by Navel oranges then the least abundant on Baladi oranges. Generally, the calculated data on Succari oranges showed that, the population of P. pergandii reached the maximum during July and there were five highly variation periods in both the growing seasons of 2011-2012 and 2012-2013. The maximal percent of pre and adult females was observed during Spring and early Summer and reached 100% of the total counted individuals during October and December in the first year, but in the second one a higher population was recorded during Summer and early Winter months. The adult males were observed during Summer and Autumn months. Results showed also that the relationship between daily mean temperature and population density of chaff scale was weak, insignificantly negative in the two growing seasons (2011-2012 and 2012-2013) and also insignificantly but positive with relative humidity. That relationship with wind speed indicated weak positive significance in the first year and strong in the second season. The relationship between dew point and insect population was weak of positive significance in both growing seasons.

Ecological studies on San José scale, Diaspidiotus perniciosus (Comstock) (Homoptera: Diaspididae) as a new insect pest on pear trees in Burg El-Arab area, Alexandria, Egypt.

The San José scale, D. perniciosus (Comstock) (Homoptera: Diaspididae) was noticed on pear trees all the year round in Burg El-Arab area (50 km West of Alexandria). Bio ecology and population fluctuations of this serious scale insect were carried out during the two subsequent seasons of September, 2004 until August, 2006. The calculated infestation rates (%) assured the presence of three peaks in both seasons. The estimated densities of fluctuating individuals of D. perniciosus on the inspected pear trees showed two distinctly prominent peaks, in addition to an overlapping one between them. It means, that the San Josè scale, D. perniciosus had three overlapping annual generations on pear trees in Burg El-Arab area under an irrigation system. The individuals of all stages could be found on trees all over the year. The population of the inspected immature stages; adult females and adult males were recorded and discussed as well as the parasitized individuals by the aphilinid parasitoid, Aphytis diaspidis (Howard) (Hymenoptera: Aphelinidae). The population density of the San José scale (SJS) reached its maximum during spring, folLowed by summer, winter, whereas the least percentage was recorded in autumn months. The obtained data showed also variable effects of the prevailing abiotic factors on the dynamical oscillation of (SJS) individuals. The daily mean temperature and the dew point were not the dominant efficient physical factors. On the contrary, it has been proved that there were either significant strong negative or positive relationships between daily relative humidity, wind speed, infestation rate, and population density of this studied insect pest.

Ultrastructure of egg shell of four different Coccoidea species in Egypt.

The present study was initiated to perform a comparative measurements of egg dimension and structure of four different species pertaining to three families of the super family: Coccoidea. These species were: Mycetaspis personata (Comstock) (Diaspididae), Ceroplastes floridensis (Comstock) (Coccidae), Pulvinaria psidii (Maskell) (Coccidae), and Icerya seychellarum seychellarum (Westw.) (Margarodidae). The studied species differed in their means of egg laying and chorion structure, which may explain the mode of insect protection. The dimensions of chorion shell, as well as the ultra structure of the egg shell of each species were examined and discussed.

Scale insects and mealy bugs (Homoptera: Coccoidea) attacking deciduous fruit trees in the western north coast of Alexandria, Egypt.

This investigation covered a survey of scale insects and mealy bugs infesting ten growing species of deciduous fruit trees in three localities in Alexandria govemorate. These localities were Merghem, Burg El-Arab, and El-Nahda about 50 Km. West of Alexandria under both rain-fed and irrigation system conditions. The common inspected fruit trees were fig, white mulberry, pomegranate, apple, pear, apricot, European plum, peach, almond, and persimmon. It was shown that a group of twenty scale insects and meaty bug species pertaining to fifteen genera belonging to six families of the super family: Coccoidea were collected and identified during the elapsing period from January to December, 2004. Among these species, Diaspidiotus perniciosus (Comstock) was recorded for the first time in Egypt. In the present study, many insect and non-insect parasitoids and predators were also found associated with these scale insects and mealy bugs on deciduous fruit trees in the three concerned localities throughout this investigation. These natural enemies were identified and recorded.

Ecological studies on the greedy scale, Hemiberlisia rapax (Comstock) (Homoptera: Diaspididae) on pear trees in burg El-Arab area, Alexandria, Egypt.

The greedy scale, Hemiberlisia rapax (Comstock) causes economic damage on pear trees under irrigation system in Burg El-Arab area (50 Km. West of Alexandria). The infestation rate of H. rapax reached its first maximum rate during August to October, and the second one occurred from January to March. The 1st highest peak of insect population occurred during September and October; the second was during January and February, and the third one corresponded to April for the 1st and the 2nd successive seasons. The statistical analysis was performed to determine the relationship among the weather factors of mean daily temperature, daily relative humidity, wind speed, and dew point in relation to the population activity of Hemiberlisia rapax. The immature stages had two peaks of fluctuation during October to November and July to August. The adult females reached their maximum rates during winter and spring months. Adult males appeared in late March in few numbers. The insect was parasitized by Aphytis diaspidis (Howard) (Hymenoptera: Aphelinidae) in maximum numbers in June and July. This parasitoid had three overlapping generations all the year round. The first in September-October; the second extended from March to May; while the third one lasted from July to September.