Safeners

Breaux. E.I.. Patanella. I.E.. and Sanders. E.F. Chloroacetanilide herbicide selectivity analysis of glntathione and homoglutathione in tolerant, snsceptible and safened seedlings. J. Agric. Food Chem., 35(4) 474-478.1987. 

Bordas, B., Komives, T., Szanto, Z., Lopata, a. Comparative three-dimensional quantitative stmcture-activity relationship study of safeners and herbicides. /. Agric. Food Chem. 2000, 48, 926-931. 

To facilitate premixes in sorghum, Ciba-Geigy developed a seed safener to ensure greater tolerance to the chloro-acetanilide mixing partners. The development of the safener had a significant impact on use of atrazine and propazine... 

In corn, the catalyst for adoption of preplant incorporated applications was not the introduction of an herbicide, but the introduction of safeners. The thiocarbamate herbicide S-ethyl dipropylthiocarbamate (EPTC) for corn weed control was first used in Illinois as early as 1961 however, the propensity for EPTC to injure com limited its use to 1% or less of the Illinois crop up to 1970 (Table 4.1). Dichlormid, a safener later packaged with EPTC, greatly improved crop safety and resulted in nearly one-quarter of the com acreage being treated with EPTC throughout the Corn Belt by 1976. 

The history of another thiocarbamate, butylate, is similar to that of EPTC. Initially marketed without a safener, butylate s propensity for crop injury resulted in some resistance to its use from farmers. When butylate was released with a safener, this combination product became widely accepted. Because EPTC was more volatile than butylate, it tended to be better suited for the cool soils of the northern Com Belt. Butylate, on the other hand, was better adapted to the southern corn-growing region of the Central Plains. 

Polyamine safening agents for phenylcarbomoylamine acid herbicides", Japan. Kokai. Tokkyo Koho 78,94,035. January 24, 1977. 

Abu-Qare, A.Q., Duncan, HJ. (2002) Photodegradation of the herbicide EPTC and the safener dichlormid, alone and in combination. Chemospere 1183-1189. 

Uses herbicide safener, in combination with clodinafop... 

Uses herbicide, safener, wheat, rye Trade names (AgrEvo)... 

Another approach has been to increase the physiological tolerance of crop plants to particular herbicides through the development of chemical antidotes or safeners. Since the introduction of this latter concept by Otto Hoffman (2) in the early 1960 s, at least five antidotes or safeners have been developed commercially (Table I). 

Research on chemical antidotes or safeners has been summarized in several reviews and published symposia (3.-9). Most of the major developments (Table I) have resulted from impirical screening programs by Industry that may have been stimulated by observations of herbicide antagonism in plants (3, 10). However, some of the research on mode of action of antidotes has been directed at finding new ways to protect crop plants from herbicides (3). The research to be discussed in this text, namely the use of subtoxic herbicide pretreatments to improve crop tolerance to selected herbicides, arises in part from research on the mode of action of R-25788 as a selective antidote for EPIC or butylate in corn. 

Table I. Conmercially important herbicide antidotes or safeners.

The following mechanisms suggested by Craig et ai. (79) by which Concep II increased down mildew might offer a means for more effective mycoherbicide weed control when using chemical safeners. 

Gianessi et al. [7] therefore compared the amount of glyphosate that had been used on herbicide tolerant soybeans in 2001 to the amoimt of mixed herbicides that would be required to achieve the same degree of weed control. For each U.S. state, an alternative mix of herbicides was composed for comparison, based on the outcomes of a survey among experts, e.g. a mix of Boimdary (metribuzin s-metolachlor), Flexstar (fome-safen), and Select (clethodim) in Iowa (Table 1). 

PatentNumber US 5645847 A 19970708 SAFENED PESTICIDAL RESIN COMPOSITION FOR CONTROLLING SOIL PESTS AND PROCESS FOR THE PREPARATION THEREOF... 

Modification of the Toxicity of Pesticides with Formulation Additives. Potentially the use of additives to modulate the toxicity of pesticides could lead to a considerable increase in their safety to non-target species, man included. This concept has been well explored and exploited in adding safeners to certain herbicides such as the thiocarbamates. These compounds stimulate defensive metabolic reactions in the crop species but not in weeds This principle has also been applied to vertebrates, but only to a very limited degree. Under some circumstances the thiocarbamate rice herbicide, molinate, may show toxicity to carp in nearby ponds. Based on a knowledge of the safeners that are active in plants, a compound was discovered that, when applied with molinate, acted as an antidote/safener for the carp (20). Little effort, either theoretical or empirical, seems to have gone into developing other such examples. 

Investigate possibilities of safening agents against resistance... 

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