Effect of initial infestation on population fluctuation and spatial distribution of Panonychus citri (Acari: Tetranychidae) on Thomson navel orange in Ghaemshahr, Iran

Citrus red mite (CRM), Panonychus citri (McGregor) (Acari: Tetranychidae) is one of the important citrus pests in different parts of the world including northern Iran. Population fluctuation and spatial distribution pattern of this pest was studied in Ghaemshahr, northern Iran during 2016–2017 in different initial infestation treatments (paired-treatment and multiple-treatment experiments) that had been designed for crop loss assessment caused by CRM. Taylor's Power Law and Iwao's Patchiness Regression methods were used to determine the spatial distribution pattern of CRM. The results showed that the highest population density of the pest was during summer of 2016 and 2017 with an average of 127.3 and 91.15 CRM per leaf, respectively, and the population declined in the fall with an average of near zero mites per leaf. The spatial distribution pattern of CRM in both years and both methods was aggregated with an exception in which it was random. It could be concluded that initial infestion with different densities of the pest affected the population fluctuation of the pest during the growing season and somewhat the spatial distribution pattern of CRM.