On-line version ISSN 1678-992X
PIZANO, M.A. and DE BAPTISTA, G.C.. RESÍDUOS DE FENITROTION EM FRUTOS E FOLHAS DE TOMATEIRO (Lycopersicon esculentum Mill) ESTAQUEADO . Sci. agric. [online]. 1998, vol.55, n.2, pp. 203-209. ISSN 1678-992X. http://dx.doi.org/10.1590/S0103-90161998000200006.
The behavior of fenitrothion in fruits and leaves of staked tomato plants was studied with gas chromatography. The field experiment begun when plants had 90 days post-transplant and consisted of four treatments: (1) a single application of fenitrothion at 100 g a.i./100 liters of water; (2) a double dose application of 200 g a.i./100 liters of water; (3) four applications at 7 day intervals at the lower dosage; and (4) control. Fruit and leaf samples were collected one day before application (-1) and at zero, 1, 2, 3, 5, 7 and 14 days post-application. Residual analysis of fruit and leave consisted of acetone extraction and partition with chloroform; extract cleaning in a florisil column and benzene elution (for leaves). Quantitative estimates were obtained in a gas chromatograph, using flame photometric detector, with a special phosphorus filter. Leaf residues were always higher than those in fruits (approximately 80 times), during all sampling intervals. Half-live degradation values of fenitrothion in fruits and leaves were: 1.6 to 1.9 and 0.7 to 0.8 days, respectively. Half-lives of persistence were similiar for both substrates: 4.2 to 7.3 and 5.6 to 6.2 days, respectively. Fruit residues immediately after application were below the official tolerance level (0.5 ppm) for treatments of 100 g a.i./100 liters in one or four weekly applications. A single application of 200 g a.i./100 liters resulted in residual levels lower than 0.5 ppm after one or more days post-application.
Keywords : Residues; tomato; fenitrothion; fruit; leaf .