Population fluctuation and spatial distribution of oak thrips, Liothrips pragensis (Thy.: Phlaeothripidae) in oak forests of Javanrud county

Oak thrips, Liothrips pragensis Uzel is found on oak trees in Zagros forests. In this study, population fluctuation and spatial distribution of this species were investigated in oak forests of Javanrud county (Kermanshah province), in 2021. Oak leaves were selected as the sampling unit. Sampling was performed every week from five different areas, so leaves were shaken on a white plastic tray and thrips specimens with a soft brush were transferred into Eppendorf tubes containing 75% alcohol. The results showed that the activity of oak thrips in all five studied areas was occurred on May and their activity and density gradually decreased until it reached its lowest level in September. The highest population density of oak thrips was observed on May with an average of 2.93 ± 0.56, 2.23 ± 0.47, 2.23 ± 0.34, and 0.90 ± 0.28 thrips per sample unit, in Sefid Barg, Bileei, Cheshme Miran and Helanie areas, respectively. However, the highest density was obtained in Hori Abad region in June with an average of 2.06 ± 0.43 thrips per sampling unit. The results of spatial distribution showed that the spatial distribution of oak thrips based on Taylor’s power law and Iwao’s methods was random and aggregated, respectively. Furthermore, based on goodness of fit, the Iwao’s patchiness method was more suitable than the Taylor’s power law method for estimating the spatial distribution of the pest.