Population Dynamics of Leafhopper (Empoasca flavescens) and Thrips (Scirtothrips dorsalis) of Castor (Ricinus communis L.)

Abstract

The experiment on population dynamics against leafhopper and thrips of castor,a field experiment was conducted during 2021 & 2022 on castor (Ricinus communis) at Regional Agricultural Research Station Palem, PJTSAU. The studies on population dynamics of leafhopper (Empoasca flavescens) revealed thatthe activity of leafhoppers was moderate to heavy with maximum of 120.8 leafhoppers/3 leaves/plant was recorded during the second fortnight of December (52 SMW, 24th-31st Dec). Leafhopper population had non-significant and negative correlation with maximum temperature (r = -0.24 and r = -0.29, respectively), whereas it had significant assocation and negative correlation with minimum temperature, morning relative humidity, evening relative humidity as well as rainfall (r = - 0.64 - 0.50, r=-0.61 and - 0.52, respectively). Thrips infestationwas observed from October first fortnight (40 SMW 1st Oct -7th Oct) to December second fortnight (52 SMW, 24th-31st Dec) with peak infestation 31.1 thrips/spike.Thrips population had non-significant and negative correlation with maximum temperature ( r = -0.29), whereas it had significant assocation and negative correlation with minimum temperature, morning relative humidity, evening relative humidity as well as rainfall (r = - 0.68, r= -0.55, r=-0.63 and, r=- 0.49 respectively). Leafhopper and thrips has significant association and positive correlation with sunshine hours (r=0.55 & r=0.51).