Study of population dynamics of whorl maggot, Hydrellia philippina (Ferino) and gall midge Orseolia oryzae (Wood-Mason) of rice in Pusa, Bihar

Results revealed that the activity of whorl maggot started to appear from 30^th standard week in both the years i.e., 2018 and 2019 with per cent mean incidence of 4.28 and 5.37 leaf damage, respectively. Incase of gall midge, the silver shoot symptom was first recorded during 31^st standard week with a per cent mean incidence of 4.97 and 5.96 during kharif 2018 and 2019 respectively. The coefficient analysis showed that maximum temperature (r = 0.025, 0.506*), minimum temperature (r = 0.702^**, 0.682^**), relative humidity morning (r = 0.106, 0.283), relative humidity evening (r = 0.493, 0.043), rainfall (r = 0.116, 0.143), wind velocity (r = 0.548*, 0.296) and evaporation (r = 0.091, 0.449) had positive relationship with the incidence of whorl maggot damage during both the years. Incase of gall midge, maximum temperature (r = 0.514*, 0.504*), minimum temperature (r = 0.855^**, 0.747^**), rainfall (r = 0.013, 0.058), wind velocity (r = 0.339*, 0.352) and evaporation (r = 0.062, 0.536*) had significant positive influence on the incidence of leaffolder damage during both the years.