The impact of growing season and cultivation systems on the dissipation of profenofos and λ- cyhalothrin on Brassica juncea: a comparative study

Abstract

This study was conducted to contour dissipation patterns of two pesticides (profenofos and λ-cyhalothrin) on B. juncea (green mustard) grown under green house (G.H.) and open field (O.F.) during dry and wet season. The dissipation data of studied pesticides were fitted into the first order kinetic equation. Based on the dissipation rate constant, k obtained, profenofos dissipates faster than λ-cyhalothrin regardless of growing system and season. The dissipation of both pesticides were found to be more rapid during dry season compare to wet season. Growing system however displayed a rather contradictory results for profenofos where during dry season, faster dissipation took place in O.F., while during wet season rapid dissipation took place in G.H. λ-Cyhalothrin on the other hand exhibits faster dissipation in G.H. during both seasons. The half-lives obtained for profenofos and λ-cyhalothrin in B. juncea were 0.66–1.8 days and 1.18–3.7 days, respectively. Based on this experiment, terminal residue obtained for profenofos and λ-cyhalothrin for B. juncea were lower than the stipulated MRL. This work was momentous to guide appropriate applications and establishment of accurate PHI of pesticides in B. juncea that will benefit farmers in a country with humid tropical climate.