Methidathion

Methicillin — see Penicillin, 2,6-dimethoxyphenyl-Methidathion insecticidal activity, 6, 576 as insecticide, 1, 196 Methine, dipteridyl-synthesis, 3, 303 Methine dyes, 1, 323-325, 332 L-Methionine, S-adenosyl-in metabolic iV-methylation, 1, 236 Methionine, dehydro- C NMR, 6, 139 X-ray crystallography, 6, 136 Methiothepin... 

Sunshine Mining and Refining Company, 249 SuperGen Inc., 249 Superior Graphite Co., 249 SUPRACIDE , methidathion, 124 SUPRATHION , methidathion, 124 Surgutneftegas (OJSC), 197 Su-Vi Chemicals Ltd., 176... 

Methidathion oxon, see Methldathion Methiocarb sulfone, see Methlocarb Methiocarb sulfoxide, see Methiocarb Methionine, see Thiram Methoxyacetaldehyde, see Alachlor Methoxyacetic acid, see 1,4-Dioxane p-Methoxybenzaldehyde, see Methoxychlor p-Methoxybenzoic acid, see Methoxychlor... 

ChemicaPPhysical. Emits toxic fumes of phosphorus, nitrogen, and sulfur oxides when heated to decomposition (Sax and Lewis, 1987). Methidathion oxon was also found in fogwater collected near Earlier, CA (Glotfelty et ah, 1990). It was suggested that methidathion was oxidized in the atmosphere during daylight hours prior to its partitioning from the vapor phase into the fog. On 12 January 1986, the distributions of parathion (0.45 ng/my in the vapor phase, dissolved phase, air particles, and water particles were 57.5, 25.4, 16.8, and 0.3%, respectively. For methidathion oxon (0.84 ng/m3), the distribution in the vapor phase, dissolved phase, air particles, and water particles were <7.1, 20.8, 78.6, and 0.1%, respectively. 

Smith, C.A., Iwata, I., and Gunther, F.A. Conversion and disappearance of methidathion on thin layers of dry soil, J. Agric. FoodChem., 26(4) 959-962, 1978a. 

Chlorpyriphos methyl, diazinon, disulfoton, fenamiphos, fenthion, isofenphos, malathion, methidathion, pyridafenthion, temephos... 

S. cerevisiae can produce H2S and SO2 in the presence of sulfur-containing insecticides such as chlorpyrifos-methyl, fenitrothion, and methidathion (Cabras et al., 1995b Eschenbruch, 1974). These insecticides did not affect fermentative activity. Quinoxyfen, belonging to the family of quinolines, showed no effect on the alcoholic fermentation using three strains of yeasts (Cabras et al., 2000 Lopez et al., 2004). 

This paper establishes toxicologically-safe levels for total residues of parathion, azinphosmethyl, methidathion and their oxons on tree foliage and reports these levels in terms of absorbance units as determined by the rapid field method. Safe levels for a new insecticide, chlorthiophos, are also proposed based on preliminary residue data. Chemical structures of the four insecticides mentioned above are shown in figures 1, 2, 3 and 6. 

Figures 1A, 2A and 3A give representative dissipation curves for parathion, azinphosmethyl and methidathion on orange trees in California (6). Parathion dissipates with the formation of considerable amounts of paraoxon. Low volume application (100 gal/acre) of these insecticides results in high levels of OP residues and thus longer dissipation times to safe levels. Azinphosmethyl does not dissipate as rapidly as parathion under field conditions. Azinphosmethyl oxon is formed during the process and dissipates slowly with time. Azinphosmethyl oxon levels were determined only for azinphosmethyl at 6.0 lb AI per 100 gal/acre. Methidathion dissipates on citrus also with the formation of its oxon.

Figures IB, 2B and 3B, drawn using the data from Figures 1A, 2A and 3A, give the dissipation curves for the total residues (thion + oxon) of parathion, azinphosmethyl and methidathion. These dissipation curves are similar to the curves obtained when OP residues are determined by the rapid field method as shown by the extensive studies conducted by Gunther et al. (5) which compare gas chromatographic values for thion + oxon with RFM values for total OP residues.

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