الفهرس 
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Abstract
The present study was conducted through two successive seasons of 2007-2009 at Faculty of Agriculture Experimental Farm, Assiut University to survey Arthropods associated with three grapevine varieties (Muscat, Thompson seedless and Azmerly). The seasonal fluctuations of the most abundant and economically injurious pests: black vine thrips, Retithrips syriacus Mayet and European red mite, Panoychus ulmi Koch. were studied as well as the quantitative effects of certain abiotic and biotic factors on the population activity of these most abundant pests were carried out.
1- Survey of arthropods associated with grapevine trees:
Data of the survey revealed the presence of 20 insect species belonging to 20 genera under 14 families of 7 orders. Moreover, mite species was represented by three species belong to three genera under two families of two orders. Intensive and extensive observations indicated that the collected insect and mite species can be classified according to their economic importance as pests included 19 insect species and two mite species. Predators represented with one species of both insects and mites.
The insect pests which had been surveyed were:
Retithrips syriacus Mayet, Thrips tabaci L., Empoasca lybica Bergevin, Aphis gossypii Glover, Planococcus spp., Russellaspis pustulans Cock, Icerya purchasi Mask, Aonidiella aurantii Mask, Chrysomphalus ficus Riley, Lepidosaphes beckii Newm, Lobesia botrana Schiff, Spodoptera littoralis Boisd, Paropta paradoxa H-Schaeff, Nezara viridula L., Schistocerca gregaria Forsk, Anacridium aegyptium L., Drosophila melanogaster Meig, Pachnoda fasciata F. and Tropinota squalida Scop.
Predaceous insect : Scolothrips longicornis Priesne.
The mite pests which had been surveyed were:
Panonychus ulmi (Koch) and Tetranychus urticae Koch.
Predaceous mite : Amblyseius hutu (Pichard and Baker).
2- Population fluctuations of R. syriacus and P.ulmi :
2.1. In the first season (2007/2008) R. syriacus started with low level in April, then increased in May and the maximum number of individuals on leaves was recorded in June and July for the three grapevine varieties. Then, the number of individuals decline rapidly during the next six months (Aug.-Jan.).
In the second season (2008/2009) the population density of this insect species showed low level of multiplicity on Muscat and Thompson seedless during April and on Azmerly during June. Then, the population increased through July and August to exhibit moderate monthly averages on the three varieties. A quick augmentation respecting the individuals were recorded in September on all grapevine varieties. Through November, December and January, the monthly averages gradually decreased, and the pest completely dismissed on February of all the investigated grapevine varieties.
2.2. The population of P. ulmi initiated at low level of abundance during April in the first season or March and April in the second season for the three grapevine varieties. Through May in the first season or May and June in the second, the population density of this mite species reached its utmost levels of abundance. The rapid descended in the level of population density was occurred through the next months, till disappeared in February in the first season and from September in the second.
3. Effects of certain abiotic and biotic factors on the population activity of some pests inhabiting grapevines:
Biotic and abiotic factors play a great role in regulating the population abundance of many insect and mite species. Therefore, the predators (i.e., Amblysieus. hutu, Scolothrips longicornis Priesner) and sampling date, as well as some physical factors, particularly (maximum temperature, minimum temperature and average relative humidity) were investigated in the present study to declare their quantitative effects on the population density of R. syriacus and P. ulmi inhabiting Muscat, Thompson seedless and Azmerly grapevine varieties.
The multi-regression analysis results between the population of R. syriacus and P. ulmi, and the predators as well as certain weather factors, during the two studied successive seasons (2007-2009) on the three grapevine varieties are investigated.
Relationship between the population density of R. syriacus and P. ulmi on Muscat, Thompson seedless and Azmerly grapevine varieties, and the fluctuation of the weather factors was statistically tested using multiple regression analysis. The weather factors studied were maximum temperature, minimum temperature and the average relative humidity, which had been recorded over each inspected date. The total number of predaceous arthropods (mites and insects) and sampling date, which had been recorded, were also studied to estimate the relative date and predatory effects in relation