Herbicides metribuzin

Mondy NI, Munshi CB. 1988. Chemical composition of the potato as affected by the herbicide, metribuzin Enzymatic discoloration, phenols and ascorbic acid content. J Food Sci 53 475-476. 

Investigations on the nature of a colored impurity that occurs during the manufacture of the triazine herbicide metribuzin led to an unusual synthesis of 2,5-dihydrazino-l,3,4-thiadiazole (156). Addition of HjOj to the dihydrazide (155) in aqueous hydrochloric acid, and storage overnight followed by a complex workup, gave (156) in a crude yield of 28% <90JHC1053>. 

The Co(II) -phenylthiourea-borax buffer system has been studied applying CSV at HMDE [69]. An irreversible peak observed at —1.5 V was attributed to the catalytic hydrogen evolution. The first reduction step, combined with the adsorptive accumulation of herbicide metribuzin at mercury electrode, has been used for its determination by adsorptive stripping voltammetry [70]. 

Davis, D.G., P.A. Olson, H.R. Swanson, and D.S. Frear (1991). Metabolism of the herbicide metribuzin by an V-glucosylIrans(erase from tomato cell cultures. Plant Sci., 74 73-80. 

Saeman, M.C. (1984). Chemical and Metabolic Oxidation of the Herbicide Metribuzin [Dissertation], Berkeley, CA University of California, p. 94. 

Scholz, K. (1982). Open Ring Structure of the Triazine Herbicide Metribuzin [SENCOR] in the Paper Published by Prestel et al. Miles Ag. Div. Report Number 86226.2... 

Lewis, W.M. (1981). New turf herbicides metribuzin for preemergence and postemergence control of crabgrass and goosegrass in bermudagrass turf. Proc. North Carolina Turf. Conf, 2. 115 pp. 

Schilling, R., G. Engelhardt, and P.R. Wallnofer (1985). Degradation of the herbicide metribuzin (Sencor) by pure cultures of Cunninghamella echinulata Thaxter ATCC 38447. Chemosphere, 14 267-270. 

Several processes may play a role in the environmental dissipation of -triazine herbicides. Dissipation processes can include microbial or chemical degradation in soil metabolism or conjugation in plants photodegradation in air, water, and on soil and plant surfaces and volatilization and transport mechanisms. This chapter will address photolytic degradation and abiotic hydrolysis of the currently used triazine herbicides, the triazinone herbicides (metribuzin and metamitron), and the triazinedione herbicide hexazinone. 

Webster, G.R.B. and G.J. Reimer (1976). Field degradation of the herbicide metribuzin and its degradation products in a Manitoba sandy loam soil. Weed Res., 16 191-196. 

Brock TCM, Crum SJH, Deneer JW, Heimbach F, Roijackers RMM, Sinkeldam JA. 2004. Comparing aquatic risk assessment methods for the photosynthesis-inhibiting herbicides metribuzin and metamitron. Environ Pollut 130 403-426. 

The photochemical decomposition of the diones (169) has been studied as a comparison with the decomposition of the herbicide metribuzin. The dependence of the reactions encountered in oxygenated solutions of varying... 

For the absorbance-based detectors, alternative cell geometries have been designed to extend the optical pathlength such as the Z-shaped cells, bubble cells, rectangular cells, and multireflection capillaries. Although manufacturing and manipulation of these special cells can pose a few operational problems, sensitivity enhancement of tenths of fold have been reported. The determination of the herbicide metribuzin and its major conversion products in soil is an example of the use of bubble cells, whereas the UV-detection of derivatized carbonyl compounds in rain is an example of the use of Z-shaped cells in environmental analysis. 

Triazinone herbicide Metribuzin and its major conversion products, deaminometribuzin, diketometribuzin,... 

J.F. Huertas-P ez, M. del Olmo huela, A.M. Garcfa-Campana, A. Gonzdlez-Casado and A. S nchez-Navarro, Determination of the herbicide metribuzin and its major conversion products in soil by micellar electrokinetic chromatography, J. Chromatogr. A, 1102, 280-286, 2006. 

The asymmetrical-triazine herbicide metribuzin was found by Arvik et al. (1973) to prevent growth of five common soil algae in liquid culture when used at a concentration of 0.5 ppm (Chlorella vulgaris and Chlamydomonas) and one ppm (Chlorococcum, Anabaena and Schizo-thrix calcicola),... 

FIGURE 10.34 Aerobic degradation of 1,2,4-triazolone herbicides (a) metamitron and (b) metribuzin. 

The pathway for the degradation of metribuzin that has been used as a herbicide has been established, and attention has been directed to the occurrence of the metabolites in leachate from agricultural soil in Denmark. Although the parent metribuzin was not found, the metabolites produced by loss of the N-amino group and the thiomethyl groups were produced and contributed to ground-water contamination (Kjaer et al. 2005). 

Freshwater copepods, 2 species 10 LC50 (24 h) effects counteracted by metribuzin, another herbicide 13... 

Naqvi, S.M., T.S. Leung, and N.Z. Naqvi. 1981. Toxicities of paraquat and metribuzin (Sencor) herbicides to the freshwater copepods, Eucyclops agilis and Diaptomus mississippiensis. Environ. Pollut. 26A 275-280. 

Cotterill [100] studied the effect of ammonium nitrate fertilizer on the electron capture or nitrogen specific gas chromatographic determination of Triazine plus other types of herbicide (Atrazine(2-chloro-4-ethylamino-6-isopropylamino, 1,3,5 triazine), Simazine (2-chloro-4.6 bis ethyl amino 1,3,5 triazine), Linuron (3,4,-chlorophenyl-l-methoxy-l-methyl urea), Metribuzin, Triallate and Phorate) residues in soil. 

A controlled release herbicide based on Metribuzin attached to poly(vinyl alcohol) has been reported via an isocyanate reaction as shown in Equation 18. Data on the release rate has been published (54). 

Savage, K.E., C.L. McCormick, and B.H. Hutchinson, "Biological Evaluation of Polymeric Controlled Activity Herbicide Systems Containing Pendant Metribuzin,"... 

The isomeric l,2,4-triazin-5-ones also have herbicidal activity, and of these the 4-amino compounds stand out. Metribuzin (3) and metamitron (4) (68SAP6804409) possess excellent selectivity, the former being manufactured on a very large scale. Metribuzin can be synthesized from 3,3-dimethyl-2-oxobutyric acid (Scheme 3). 

Landgraf, M. D., da Silva, S. C., and Rezende, M. O. O. (1998). Mechanism of metribuzin herbicide sorption by humic acid samples from peat and vermicompost. Anal. Chim. Acta. 368,155-164. 

On the other hand, the broad weed control spectrum of chloramben, which was introduced in 1959, brought with it widespread acceptance. As an over-the-row band for control of both broadleaf and grass weeds, cost was minimized. With good crop tolerance, chloramben dominated the early soybean herbicide market. During 1972, 85% of the product was applied as the granular formulation (Table 4.2). However, as application practices changed for the soybean crop, banded applications became an inconvenience. Herbicides such as metribuzin (a triazine herbicide), linuron, and bentazon, which could be applied as an affordable broadcast treatment, soon became products of choice, and the marketing of chloramben was eventually discontinued in 1990. 

The ability of one product to complement the characteristics of another has also had an effect on product acceptance. Although alachlor initially was used by itself as a banded granular grass herbicide on com and soybean, it was the tank mixes with broadleaf herbicides that propelled its success. Combinations of atrazine-alachlor, metribuzin-alachlor, and linuron-alachlor became very common. Alachlor replaced essentially all propachlor use on field corn over the 4-year period from 1972 to 1976, not only as a result of less hazardous handling characteristics (Table 4.1), but also as a consequence of its success in tank mixes. 

The triazine herbicides can be divided into four different structural classes chlorotriazines, methylthiotriazines, methoxytriazines, and atypical or asymmetrical triazines. The chlorotriazine group includes atrazine, simazine, pro-pazine, terbuthylazine, and cyanazine. The methylthiotriazine group includes ametryn, prometryn, and terbutryn. The methoxytriazine group will include prometon and secbumeton. Hexazinone and metribuzin were chosen to represent the atypical triazine group. The plant metabolism of the most researched member of each triazine group will be discussed in detail to cover all major biological and chemical transformations reported in the literature. 

Metribuzin is a member of the substituted as-triazinone group of herbicides. Activity is due to interference with photosystem II electron transport in plant chloroplasts (Dodge, 1983). The metabolism of metribuzin in plants has been the subject of many short-term and long-term studies dating back to the early 1970s. 

Gawronski, S.W., L.C. Haderlie, R.H. Callihan, and H. Gawronska (1986). Mechanism of metribuzin tolerance Herbicide metabolism as a basis for tolerance in potatoes. Weed Res., 26 307-314. 

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