This study evaluated the efficacy of three bacterial species. Acinetobacter sp. (concentration 2.237×108 cfu/ml), Bacillus subtilis (concentration 2.470×108 cfu/ml) and Bacillus qassimus (concentration 3.320×108 cfu/ml) were tested against the two-spotted spider mite, Tetranychus urticae, infesting eggplants under laboratory and greenhouse conditions. In addition, we studied their side effects on the predatory mite, Phytoseius plumifer. The highest efficiency rate on T. urticae was observed with Acinetobacter sp. sprays. Three days after treatment, mite mortality reached 87.15 and 77.29 % under laboratory and greenhouse conditions, respectively. Moreover, the mortality rates were significantly lower (72.22 and 67.11 % and 70.74 and 65.19 %) using B. subtilis and B. qassimus under lab and greenhouse conditions, seven days after treatment. The predatory mite, P. plumifer, showed higher tolerance than T. urticae to the three bacterial preparations. The results of this study indicated that Acinetobacter sp. has a strong efficacy on T. urticae and slightly affected the predatory species herein tested. This study introduces a potentially new strategy for biological control of phytophagous mites.

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The Paleozoic formations in the Middle East contain some of the world's richest petroleum deposits, as they include excellent source and reservoir rocks. The Paleozoic rocks were deposited on the northern continental shelf of the Gondwanan continent at relatively high latitudes, and provide evidence of the Late Ordovician glacial event and associated sea-level changes. They also contain unique fossil remains. The Paleozoic formations exposed in the Al-Qassim Province in Saudi Arabia are well-suited to become important sites for geotourism. Because the sedimentary formations are well-exposed and are easily accessible, they have strong capacity for development as tourist destinations. In this paper, we describe eight localities and their significance as potential educational sites for geology and palaeontology, as well as the archeological and economic significance of the Paleozoic formations of Saudi Arabia. The cultural and tourist infrastructure is summarised and a two-day field excursion is proposed.