Sampling approaches of the Hindustan citrus mite (Schizotetranychus hindustanicus) in Brazilian citrus orchards and climatic factors affecting its population dynamics

The Hindustan citrus mite, Schizotetranychus hindustanicus (Acari: Tetranychidae), is an invasive pest in South America and constitutes a threat to Brazilian citriculture. This study aimed to determine the contribution of weather variables to the seasonal abundance of S. hindustanicus and the best sampling scheme (sampling variable and unit) for this mite. Populations of S. hindustanicus were monitored monthly in an orange orchard for 31 months in Roraima state, Brazil. Eggs, mobile stages, and the symptoms caused by S. hindustanicus were sampled in different combinations of canopy quadrants, vertical tree strata, and branch sections. The optimal sampling variable and sampling unit for S. hindustanicus scouting were determined according to fidelity and precision criteria. Rainfall and high air temperature were the main factors reducing S. hindustanicus populations. The most suitable variable for S. hindustanicus sampling was egg count. The optimal sampling unit was a leaf collected in the central section of branches located in the middle tree stratum. In addition, the sample should be taken from the southwest quadrant. Collectively, this study adds to the understanding of S. hindustanicus population dynamics and provides a sampling scheme for better management of this pest.