Effects of climatic parameters on Tetranychus urticae (Acari: Tetranychidae) populations based on remote sensing in the southeastern Caspian Sea

Tetranychus urticae Koch (Acari: Tetranychidae) is known to be a serious pest in cotton fields worldwide. In this research, monitoring of T. urticae was done based on satellite data by using the time series of vegetation index and climatic factors through near real-time assessment. The current study aimed to determine correlations between the population dynamic of T. urticae and the effects of Absorbing Aerosol Index (AAI) depicted by Sentinel-5 Precursor, Sentinal-2 NDVI (10 m), Land Surface Temperature (LST), MODIS-Evapotranspiration (ET), and CHIRPS precipitation. Spider-mite outbreak was found to be coincided with wheat harvesting where several dusty days were experienced with a high aerosol index of 0.167. Rainfall had a significant negative correlation with T. urticae populations (R2 = 0.378), while a threshold precipitation level of at least 2 mm was estimated for cleaning up the canopy. No significant pattern could be found between temperature and T. urticae populations until August 2020. Yet, significant positive relationships were weekly observed during August 2020 (R2 = 0.3519, 0.1283, 0.1675, and 0.178). Evapotranspiration (ET) displayed a statistically synchronous relationship with T. urticae dynamism (R2 = 0.637). Also, there was a positive correlation between increasing NDVI and T. urticae population until August 2020 and then, it changed to a negative pattern (R2 = 0.273 and 0.139). Based on these findings, AAIs of Sentinel-5 and MODIS-evapotranspiration had the potential to forecast spider-mite population with high temporal resolution.