ACEPHATE AND ITS METHAMIDOPHOS METABOLITE IN EGGPLANT FRUITS TREATED WITH MONSTER 40EC

Abstract

Monster 40 EC was applied to eggplant plants. Its fate in fruits was studied. There were two
applications in our treatments as following one application of 8g a.i. acephate/8L water and one
application of 32g a.i. acephate/8L water. Samples of eggplant were random collected from treated
plants after a time elapse of 0 (three hours), 2, 4, 6,…, and 60 days after insecticide treatments. The
quantitative determination of acephate and methamidophos were done by GC-MS. Investigating the
relationship between acephate and methamidophos demonstrated that 6.3 -13.5% of acephate was
degraded into methamidophos in eggplant fruits. The calculated half-life of acephate was 4.3 days. The
methamidophos was found to be more persistence than acephate with 11.4 days. The evolution of the
acephate and methamidophos concentration behaviour in eggplant led to the behaviour empirical
equations: Y = 1.926t0.55e
-0.21t for acephate (one application of 8g a.i. acephate/8L water), Y =
4.029t0.676e
-0.228t for acephate (one application of 32g a.i. acephate/8L water), Y = -0.0007t2+ 0.0197t+
0.016e-0.134t for methamidophos (one application of 8g a.i. acephate/8L water) and Y = -
0.0008t2+0.027t+0.036e-0.134t
for methamidophos (one application of 32g a.i. acephate/8L water).