Journal of Advances in Biology & Biotechnology

Aims: Onion (Allium cepa L.) belongs to family Amaryllidaceae (Alliaceae) is one of the most important commercial vegetable and condiment crop grown in India. Given the economic significance of the crop, the current study was conducted to determine the population fluctuations in thrips population in relation to weather parameters.

Study Design: RBD (One factor Analysis).

Place and Duration of Study: The experiment was carried out at Vegetable Research Station, ARI, SKLTSHU, Rajendranagar, Hyderabad during Rabi 2023-24.

Methodology: 300 m² plot was demarcated for seasonal incidence studies and the area was divided into five quadrants i.e., four on the corners and fifth was taken in the middle of the plot. The observations were recorded on the number of thrips per plant by selecting 10 plants randomly from each quadrant at weekly intervals i.e., SMW wise from transplanting till harvest during morning hours between 7.00 AM to 9.00 AM through visual counting by tapping method using 10X magnifying lens (Apexel 2 in 1 12x/24x Super Macro Mobile Lens).

Results: The initial infestation of thrips (5.64 thrips/plant) was observed during the seedling stage i.e., fifteen days after transplantation (51^st SMW) and the peak population of the (42.34 thrips/plant) was recorded during 8^th SMW at the physiological maturity stage. It was observed that there was a significantly positive correlation with maximum temperature (r=0.831**) and minimum temperature (r=0.602*), was found to be non-significant and negatively correlated with morning relative humidity (r=-0.496), significant and negatively correlated with evening relative humidity (r=-0.837**).

Conclusion: Studies on the seasonal abundance of thrips in Rabi onion are essential for understanding their population fluctuations and aid in developing forecasting models and devising appropriate management strategies based on the crop’s growth stage.