The aim of this study was to investigate the effect of site and temperature on the percentage of leaves infested by the two-spotted spider mite, Tetranychus urticae Koch, and on the density of the spider mite and its predators on three crop species of economic importance. From February 2014 to January 2015, a survey was conducted on cucumber (Cucumis sativus L.), eggplant (Solanum melongena L.) (plots situated at Abu-sawyer and Sarabium regions, Ismailia, Egypt) and moringa (Moringa oleifera Lam.) (plots situated on the east side of the Suez Canal and El Koraim regions, Ismailia, Egypt). Results showed that there were monthly variations on the percentage of infested leaves, and on the density of the adults of T. urticae and its predators. The significant highest density of T. urticae adults was recorded in April on cucumber and eggplant, and in December on moringa. The highest density of T. urticae was recorded in Sarabium region for cucumber and eggplant, and in El-Koraim region for moringa. Three predator species were detected on cucumber and eggplant: Phytoseiulus persimilis Athias-Henriot, Scolothrips longicornis Priesner and Stethorus gilvifrons Punctillum. No predator was recorded on moringa. The density of predators was affected by site and temperature. In conclusion, sites and monthly variations of the temperature apparently were key factors affecting spider mite and its predator’s population, and their effects were host plant dependent.