Ghazaleh Amooei Maleh Ali Moghimian Sooraki Mohammad Reza Damavandian Behnam Amiri Besheli Department of Plant Protection, Faculty of Cultural Science, Sari Agricultural Sciences and Natural Resources University, Sari, Iran Arthropods ISSN 2224-4255 http://www.iaees.org/publications/journals/arthropods/online-version.asp 2025 14 4 160 173 International Academy of Ecology and Environmental Sciences Hong Kong 29 March 2025 5 May 2025 1 December 2025 citrus cottony scale water-washing mineral oil ovisac nymph The citrus cottony scale, Pulvinaria aurantii Cockerell damages citrus trees in Mazandaran province every year. The study was conducted in two separate experiments in Miandorood city. The experimental design was completely randomized in both experiments and four treatments (control, two, three and four times of waterwashing) and four treatments (control, Chlorpyrifos at a concentration of 2L/1000L, water-washing and mineral oil at a concentration of 1%) in 5 replications were considered in the first and second experiments, respectively. In first experiment, the lowest egg sac was obtained in the two times of water-washing with an average of 3.80 +- 0.37 eggs per 20 leaves and the lowest number of nymphs was observed in the four times of water-washing with an average of 247.80 +-7.32. In second experiment, the highest number of egg sacs in different dates was obtained for control with average of 30.60 and 21.20 egg sacs per five leaves and the highest number of egg sacs was obtained for water-washing with an average of 25.60. The highest number of live nymphs in all dates was obtained for control treatment. Also, the lowest number of nymphs in different dates were counted for Chlorpyrifos treatment with an average of 450.4, 351.0 and 156.0, respectively. The lowest number of nymphs was obtained for mineral oil treatment with an average of 9.4. http://www.iaees.org/publications/journals/arthropods/articles/2025-14(4)/water-washing-control-of-citrus-cottony-scale.pdf