Fungicides, thiocarbamates

Manganese Ethylenebis(thiocarbamate). Maneb [12427-38-2] (C4HgMnN2S (1), is a yellow powder used as a leaf and soil fungicide (see Fungicides, agricultural). Maneb is obtained by treating disodium ethylenebis(dithiocarbamate) with an aqueous solution of maganese(II) sulfate (37). 

The anhydride of 1,8-naphthalenedicarboxyHc acid has fungicidal properties (97). This anhydride has been commercially introduced, under the trade name Protect, as a seed treatment (eg, for com) to prevent injury to the seed by thiocarbamate herbicides. The effectiveness of the antidote 1,8-naphthaHc anhydride has also been successfully studied with several plants and herbicides (98,99). 

Carbamate pesticides are used as (1) insecticides, (2) fungicides and (3) herbicides. Insecticides are generally derived from carbamic acid fungicides, from thiocarbamic acid. The herbicide carbamates are a more complex class of compounds. Tables 21 and 22 list some commercial carbamate pesticides in approximate order of decreasing toxicity. It should be noted that the relative classification of highly and moderately toxic is no measure of the relative carcino-, muta- or teratogenicities of these carbamates, since it is based solely on acute LD q data (Morgan, ref. 20). 

Bisdi thiocarbamates Fungicides Maneb, Zineb, Ziram... 

Studies on another thiocarbamate fungicide (nabam), revealed that a 100 g/ml solution of nabam increased hatching of sugarbeet nematode eggs compared to treatment with tap water alone (38). 

Miyashita, Y, Ohsako, H., Takayama, C. and Sasaki, S. (1992). Multivariate Structure-Activity Relationships Analysis of Fungicidal and Herbicidal Thiocarbamates Using Partial Least Squares Method. Quant.Struct.-Act.Relat, 11,17-22. 

Carbamate compounds are usually subdivided into at least three main groups with respect to their structure and general use (see Figure 1) insecticides, herbicides, and thio- or dithiocarbamates. A variety of R groups may be substituted in the molecule producing, as is the case for insecticides, a variety of alkyl or aryl esters of carbamic acid. Although technically characterized as carbamate pesticides, thio- and di-thiocarbamate fungicides are not included in this... 

S. (1992) Multivariate structure-activity relationships analysis of fungicidal and herbiddal thiocarbamates using partial least squares method. Quant. Struct. -Act. Relat., 11, 17—22. 

Serio R, Long RA, Taylor JE, et al. 1984. The antifertility and antiadrenergic actions of thiocarbamate fungicides in laying hens. Toxicol Appl Pharmacol 72 333-342. 

Many fungicides and insecticides also contain one or more sulfur atoms. This is certainly true of dithiocarbamates, reduced to form thiocarbamic acids due to the oxidation-reduction balance. These compounds are reputedly as unstable as their oxygenated counterparts. Thiocarbamic acids are precursors of isothiocyauates, which constitute the active ingredients in fungicides (Figure 8.22). 

G4 18 Squalene-epoxidase Thiocarbamates / allylamines Pyributicarb/ naftifine Not used as agricultural fungicides... 

The dithiocarbamates include zinc dibutyldi-thiocarbamate (ZDBC), zinc diethyldithiocarbamate (ZDEC) and zinc dimethyldithiocarbamate (ZDMC). In the rubber industry, the carbamates are principally used in gloves, condoms and elastic bands. Due to their chemical similarity with thiurams, the potential for cross-reactivity between these groups exists (Con-de-Salazar 1990a Knudsen and Menne 1996). The greatest use of carbamates is not in rubber but in pesticides and fungicides (Table 8). 

Derivatives of thiocarbamic acid are a family of very important fungicides used in many plant-care products. Manganese salts (maneb), zinc salts (zineb), sodium and iron salts have no action on aluminium, whatever their degree of dilution. On the other hand, copper salts of dithiocarbamic acid may attack aluminium. 

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