Seasonal Incidence of Thrips, Thrips tabaci Lindeman infesting Cumin, Cuminum cyminum L.

Abstract

An experiment was conducted to study the seasonal incidence of thrips, Thrips tabaci Lindeman, infesting cumin (variety GC-4) at the Instructional Farm, Department of Entomology, College of Agriculture, Junagadh Agricultural University, Junagadh, during the Rabi season of 2019. The incidence of thrips started in the third week of December (51^st Standard Meteorological Week or SMW), corresponding to 20 days after sowing (DAS), and continued until the third week of February (8^th SMW), with thrips population ranging from 0.4 to 22.79 thrips per plant. The first peak of infestation (22.79 thrips per plant) was observed during the third week of January (2^nd SMW). Following this peak, the thrips population gradually declined and reached 5.21 thrips per plant by the third week of February (8^th SMW). The thrips population exhibited a continuous increase from germination until the first peak, after which it consistently decreased. The correlation between thrips population and weather factors revealed a negative and non-significant relationship with minimum temperature (MinT: -0.281) and mean temperature (MeanT: -0.528). A significant positive linear correlation was observed between the thrips population and bright sunshine hours (BSS: 0.716*). Additionally, maximum temperature (MaxT: -0.541), wind velocity (WV: -0.441), and evening relative humidity (RH₂: -0.451) showed negative correlations with the incidence of thrips. Morning relative humidity (RH₁: 0.342) was positively but non-significantly correlated with the thrips population.