Seasonal phenology of chilli thrips on citrus trees: Insights from a two-year screenhouse investigation

Chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae), is an invasive polyphagous pest that can cause direct and indirect damage to many crops. While considered a secondary pest for citrus in open groves, it has inflicted severe damage on citrus trees in CUPS (Citrus Under Protective Screen). This study aims to assess the seasonal phenology of chilli thrips over two years and investigate their spatial distribution during peak populations. The present study examined the seasonal abundance of chilli thrips in CUPS at 3 different sites from February 2022 to February 2024. To monitor the chilli thrips population, the study evaluated two different methods including alcohol washes and yellow sticky cards. Results indicated increased thrips density during March-April and July-September, with varying peak times depending on the sampling method. Sticky cards revealed a peak in adult thrips during the spring, coinciding with heavy flush production, while alcohol washes showed juvenile peaks in fall. Spatial analysis indicated a higher adult population along screenhouse edges in March-April, with the population spreading throughout CUPS by July-September. These insights are critical for optimizing chilli thrips management practices in CUPS, ensuring better protection for citrus crops.