Oximes as Seed Safeners for Grain Sorghum (Sorghum bicolor) to Herbicides

Abstract

Studies in growth chambers indicated that CGA-43089 {α-[(cyanomethoxy)imino] benzeneacetonitrile} applied at a rate of 1.25 g/kg of seed reduced the phytotoxicity of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], bensulide [o,o-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl) benzenesulfonamide], EPTC (S-ethyl dipropylthiocarbamate), UBI-S734 {2-[(1,2,5-dimethylphenyl)ethylsulfonyl] pyridineN-oxide} and MBR-18337 {N-[4-(ethylthio)-2-(trifluoromethyl)phenyl] methanesulfonamide} to grain sorghum [Sorghum bicolor(L.) Moench] during seed germination and seedling emergence. The protected sorghum tolerated metolachlor over a wider range of rates than it tolerated the other herbicides. CGA-43089 did not protect sorghum from the phytotoxicity of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine). Of seven other oximes tested as seed treatments, dimethylglyoxime, benzophenone oxime, pyridine-2-aldoxime, benzoin-α-oxime, and methyl thioacetohydroxamate showed promise for increasing the tolerance of grain sorghum to metolachlor. In general, higher rates of these oximes than the rate of CGA-43089 were required for equivalent protection of sorghum.

Effects of CGA-43089 on Responses of Sorghum (Sorghum Bicolor) to Metolachlor Combined by Ozone or Antioxidants

“…The initial slight injury of sorghum seedlings by metolachlor in the presence of the protectant CGA-43089 may be overcome by the plants later. Other investigators (2,29) have reported that, at the end of the growing season, the yields of sorghum plants protected with CGA-43089 and treated with metolachlor were equal or even better than those of the controls.…”

“…Today, the use of herbicide antidotes or crop protectanrs is an accepted practice in modern weed -management programs (1,22). CGA -43089 is a recently introduced herbicide antidote that enables grain sorghum to tolerate metolachlor and other acetanilide herbicides (2,4,5,6,13,19,21,26). Extensive evaluations under field conditions revealed that seed dressings with 1.25 and 1.5 g of CGA-43089/kg of seed protected sorghum against injury from metolachlor applied at rates as high as 4.0 kg/ha (6).…”

Herbicide Safeners: Effective Tools to Improve Herbicide Selectivity

“…The oxime and aldehyde derivatives tested, in terms of decreasing safening effectiveness, were dimethyglyoxime > benzophenone oxime > pyridine-2-aldoxime > benzoin--oxime > methyl thioacetohydroxamate >pyridine-2-aldoxime methiodide > 5-nitro-furancarboxyaldehyde [22]. CAMM evaluations of the oxime ether analogues cyometrinil, oxabetrinil and fluxofenim revealed that as the effectiveness of the safener increases so does its molecular similarity to metolachlor [20].…”

The Effect of Salicylic Acid and 20 Substituted Molecules on Alleviating Metolachlor Herbicide Injury in Rice (Oryza sativa)

“…The first commercialized herbicide safener, 1,8-naphthalic anhydride (NA), was discovered in 1978 by Hoffman et al and was used to protect corn from thiocarbamate herbicide damage [13][14][15][16]. Synthetic herbicide safeners such as fenclorim, dichlormid, flurazole, fenchlorazole, and dymrone have since been commercialized for crop protection [17][18][19][20]. However, some commercially available herbicide safeners (e.g., dichlormid, benoxacor, and furilazole) are toxic to both aquatic organisms and mammals [21].…”