Measuring the loss of pyrethroid insecticide after spray in brinjal ecosystem in Bangladesh

ABSTRACT: The field study was undertaken to estimate the application loss of synthetic pyrethroid (Cypermethrin 10EC) insecticide through soil and air at different days after transplanting of brinjal. The study was conducted in the experimental farm of the Department of Entomology, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, Bangladesh during summer season (February to June 2016). Cypermethrin sprayed at 10 days interval @ 1 ml l-1 of water was highly deposited on the brinjal plant at 100 days after transplanting (DAT) (53.20±3.20%) and the lowest deposition was at 30 DAT (26.90 ± 2.69%). The drift loss of cypermethrin was ranged from 3.40±0.24 % at 50 DAT to 5.60± 0.34% at 120 DAT in air on the other hand 41.70± 2.92% at 100 DAT to 69.60± 6.96% at 30 DAT in soil. While cypermethrin sprayed @ 2 ml l-1 of water at 15 days interval, the same results were observed i.e., 1 ml l-1 of water applied at 10 days interval and 2 ml l-1 of water at 15 days interval showed the almost similar results. The loss of cypermethrin was reduced day by day as the brinjal plant canopy and the plant height increased with the time. The highest drift loss was 73.10±7.31% at 30 DAT and the lowest was 46.80±3.28% at 100 DAT as the brinjal plant height and canopy increased.

Keywords: Estimation, drifting loss, cypermethrin 10EC, Solanum melongena L.