pests. Multidimensional effects including shifts in microbial counts
[44] and differential biochemical processes [15] have been reported
due to application of synthetic pyrethroid insecticides to different
field crops, but their comparative residual effects on microbial
growth and activities in the tea garden soils of the Himalayan terai
regions of West Bengal have rarely been studied.
The objectives of the present study were to investigate the effects
of four commonly used synthetic pyrethroid insecticides viz.,
cypermethrin, deltamethrin, fenvalerate and permethrin at their
recommended field application rates on microbiological activities
in relation to aerobic non-symbiotic N2-fixation and mineralization
of N in a tea garden soil of the Himalayan terai region of West
Bengal, India.