Tarbiat Modares University Journal of Agricultural Science and Technology 1680-7073 27 1 2025 01 01 Population Changes and Spatial Distribution Pattern of Date Palm Spider Mite Oligonychus afrasiaticus (McGregor) in Natural Conditions of Ramshir, Khuzestan Province, Iran 203 216 17011 10.22034/JAST.27.1.203 EN Manuchehr Jahangiri Department of Plant Protection, Faculty of Agriculture, Agricultural Science and Natural Resources University of Khuzestan. Leila Ramezani Department of Plant Protection, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Khuzestan, Islamic Republic of Iran. Ebrahim Tamoli Torfi Department of Plant Protection, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Khuzestan, Islamic Republic of Iran. Journal Article <span>The date palm dust mite Oligonychus afrasiaticus (McGregor) is one of the most important pests of the date palms Phoenix dactylifera L. around the world. This pest causes reduction in the economic value of the product, and sometimes its damage reaches up to 100% in the southern provinces of Iran. The population fluctuations and spatial distribution of this pest on two more common varieties (Sayer and Barhi) were investigated in Ramshir City, Khuzestan Province, southwestern Iran. For this purpose, two date palm plantations of 2 ha that had those two varieties of date palm trees were selected, and 10 trees of each variety in each orchard were selected randomly. Sampling was done from North, South, East, and West of each date palm every four days from mid-May to early November, during 2020 and 2021. The results showed that the spider mite appeared on the clusters of two varieties from the beginning of June, and the peak population of mites on both varieties was recorded in September, in both years. Significant difference was observed between different sampling times during those two years and the two varieties: Sayer (F₁._{916, 9.580}= 183. 695, P< 0.0001) and (F_{2.344, 11.720}= 58. 104, P< 0.0001) and Barhi (F_{1.541, 4.622}= 89.010, P< 0.0001) and (F_{1.688, 5.065}= 31. 137, P</span> https://jast.modares.ac.ir/article_17011_25819c8fe224033cc89bafa6a16cdd04.pdf