Temporal Trends in the Population of Onion Thrips and Associated Natural Enemies

Onion (Allium cepa L.) is a major horticultural crop in India valued for its culinary, medicinal, and nutritional properties. However, its productivity is significantly threatened by onion thrips (Thrips tabaci Lindeman), a globally distributed pest known for causing substantial yield and quality losses. The present study was conducted over two consecutive rabi seasons (2017–2019) at the Entomological Research Field, Chiplima, OUAT, Odisha, to evaluate the seasonal incidence of T. tabaci and its natural enemies. Observations revealed that thrips population initiated during the 50^th standard meteorological week (SMW), peaked at 24.86 thrips/plant in the 8^th SMW, and declined thereafter. Peak incidence was associated with dry, moderately warm weather, particularly low rainfall and high morning humidity. Significant correlations were observed between thrips abundance and key weather variables such as maximum and minimum temperature, relative humidity, and rainfall. Additionally, natural enemies including Spiders, green lacewing and coccinellids were documented as major biocontrol agents. The study underscores the influence of climatic parameters on thrips population dynamics and highlights the potential role of natural enemies in regulating infestations, offering valuable insights for optimizing sowing time and ecological pest management strategies in onion cultivation.