Benzadox
Weed control herbicide
From Wikipedia, the free encyclopedia
Benzadox is an amide herbicide, first discovered in 1966 to control kochia on sugarbeet crops.[6] Commercial benzadox products are often sold as benzadox-ammonium, benzadox's ammonium salt.[1] See that page for its chemical properties. Benzadox is not known to be in current use,[2] and most research about it seems to be from the 1960s and 1970s.
| |
| Names | |
|---|---|
| Preferred IUPAC name
(benzamidooxy)acetic acid | |
| Other names | |
| Identifiers | |
3D model (JSmol) |
|
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.023.685 |
| EC Number |
|
PubChem CID |
|
| UNII | |
CompTox Dashboard (EPA) |
|
| |
| |
| Properties | |
| C9H9NO4 | |
| Molar mass | 195.174 g·mol−1 |
| Appearance | Off-white solid[5] |
| Odor | Odourless[5] |
| Melting point | 140 °C (284 °F; 413 K) [5] |
| Hazards | |
| GHS labelling:[5] | |
 | |
| H302 | |
| P264, P270, P301+P317, P330, P501 | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
>2500 mg/kg (rat, benzadox-ammonium)[2] |
| Related compounds | |
Related compounds |
Benzadox-ammonium |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
Benzadox appears to work by inhibiting photosynthesis, with strong inhibition of alanine aminotransferase and aspartate aminotransferase.[7]
Kochia control
Kochia was the hardest weed to control in sugarbeet around Colorado, Nebraska, Montana and Wyoming. It can emerge at any time while growing sugar beet, and grows 6 inches to 6 feet high. Benzadox came as a breakthrough since it could be applied to weeds post-emergently and selectively on sugarbeet. Selectivity on sugarbeet had been difficult, as kochia belongs to the same chenopodiaceae family.[6]
Applied to sugar-plots in 1967 and 1968, benzadox improved yields from 740, and 2250 lbs/ac. in an unweeded control, to 960 and 3640 lb/ac with 1 lb/ac. of benzadox, up to 4860 and 7920 lb/ac. with 4 lb/ac. of benzadox. No benzadox treated plot had as high a yield as the hand-weeded plot, at 7020 and 8990 lb/ac., due to some weeds persisting and benzadox's crop injury at higher rates to the sugarbeet. The sugar content as a percentage was notably higher in the plots which were hand-weeded or treated with 2 lb/ac. or more of benzadox, because of the reduced competition from weeds.[6]
Rain shortly after herbicide application reduced the effectiveness to virtually nothing, though rain 8 hours after application had relatively little effect. Higher temperature, 70°F compared to 55°F, increased crop injury a lot, though weed control was unaffected.[6]
Commercialisation
It has been manufactured by Murphy Chemical Co and DowElanco.[2]
"Topcide" was a brand name of Gulf Oil Corporation, Agricultural Chemicals Division, with 22.5% benzadox-ammonium by weight, or 2 pounds per US gallon, recommending 1 gallon per acre to be sprayed, (2 lbs per acre active ingredient, or 2.24 kg/Ha) from a tractor sprayer. The 1970 version of the label says control is reduced if the temperature is below 55°F (13°C) or if it rains within 8 hours of spraying. Weeds turn brown within 2 to 5 days, and temporary yellowing or stunning of beets might occur. The mixture was not to be mixed with other herbicides.[8]