Effect of temperature and relative humidity on the seasonal abundance of water hyacinth weevil, Neochetina eichhorniae Warner and N. bruchi (Hustache)

Studies revealed that temperature had significant role on activity of Neochetina eichhorniae during winter and on N. bruchi during summer. However, no significant effect of R.H. was observed on both the cases. The number of adults of N. eichhorniae during summer was maximum (2.5) at 24.0°C-32.3°C temperature and minimum (1.16) at 21.9°C-27.9°C temperature; while the same during winter was maximum (3.44) at 12.5°C-23.5°C temperature and minimum (2.10) at 10.4°C-21.3°C temperature respectively. In case of N. bruchi it was maximum (2.5) at 24.0°C-32.3°C temperature and minimum (1.63) at 21.9°C - 27.9°C temperature; whereas the same duringwinter was maximum (1.50) at 10.8°C-20.9°C temperature and minimum (0.86) at 10.4°C-21.3°C temperature respectively.