Chemistry:Dalapon
Dalapon, chemical name 2,2-dichloropropanoic acid, (shortened: 2-DPA), is a selective herbicide active ingredient; its major use is controlling perennial grasses on crops, including sugar cane and sugar beet.[1][2]
"Dalapon" is not a tradename, but a recognised common name.[1] It is usually sold as a salt form, e.g. dalapon-sodium, dalapon-calcium or dalapon-magnesium; most commonly dalapon-sodium.
As of 2026, dalapon is available in Australia.[3] Its use is no longer authorized in France.[4] It was registered in the USA in 1969, and delisted in 1989. The first public use came in 1954.[5]
Properties
Dalapon is an organochloride, carboxylic acid herbicide.[5] In pure form, it is a colorless liquid that freezes near room temperature.[6]
Safety
Dalapon is readily absorbed and disperses widely in the body, but has no observable acute effects. The EPA thinks it safe for a child to ingest 3 mg of dalapon per day for 10 days or 0.3 mg daily for seven years, in drinking water. If chronic, above-limit exposure occurs, dalapon might make the kidney heavier.[7]
Mechanism of action
It is an inhibitor of some enzymes that process pyruvate.[8]
Applications
Dalapon has been registered (as the sodium salt) for use on pasture, fruits (inslcuding apples, bananas, black and red currants, cherries, peaches, apricots, citrus, pears), cotton, lucerne, maize, potatoes, soybean, sugar cane, sunflower, tea-trees, tobacco, vines and non crop areas, including irrigation channels and drains.[3]
In the USA, dalapon was sold as dalapon-sodium or a mixture of dalapon-sodium and dalapon-magnesium. In 1982, approx. 8 million pounds (3,600 t) was used, 93% of which was for non-food uses in 1984, and most of the food use was on sugarbeet.[7]
On most of those crops, it is recommended to be sprayed (when using a 740 g/L water-based formulation) at 3.7-7.4 kg/Ha (active ingredient) (3.3-6.6 lb/ac), but with some situations can be 1.85-14.8 kg/Ha (1.65-13.2 lb/ac).[3]
Environmental Fate
In soil, dalapon is mainly reduced by leaching and microbial degradation. It leaches readily. Without microbes, degradation is slow. Dalapon persists for two to four weeks in typical farm soil, though up to six months has been seen in forests.[7]
In water, the half-life is several months when cold. It degrades mostly by hydrolysis and microbial degradation. Hydrolysis forms pyruvic acid. In good conditions for microbes, the decomposition will probably finish inside of a month. Photolysis may or may not be a significant sink for dalapon.[7]
Bioconcentration is not expected to be a concern. In the atmosphere, dalapon should be reduced by photolysis with a half life of 72 days.[7]
References
- ↑ 1.0 1.1 "Index of common names of pesticides". BCPC. http://www.bcpcpesticidecompendium.org/index_cn_frame.html.
- ↑ "Dalapon". http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/dalapon-ext.html.
- ↑ 3.0 3.1 3.2 Cite error: Invalid
<ref>tag; no text was provided for refs named4f leaflet - ↑ "Retrait de l'autorisation de mise sur marché des préparations contenant du Dalapon.". 18 August 2002. https://www.legifrance.gouv.fr/jopdf//jopdf/2002/139/JO200213961ALL.pdf.
- ↑ 5.0 5.1 Cite error: Invalid
<ref>tag; no text was provided for refs nameddatabase - ↑ "Dalapon". http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/dalapon-ext.html.
- ↑ 7.0 7.1 7.2 7.3 7.4 "Technical Factsheet on: DALAPON". US EPA. https://archive.epa.gov/water/archive/web/pdf/archived-technical-fact-sheet-on-dalapon.pdf.
- ↑ Halestrap, A. P. (1975). "The mitochondrial pyruvate carrier. Kinetics and specificity for substrates and inhibitors". Biochemical Journal 148 (1): 85–96. doi:10.1042/bj1480085. PMID 1156402.
External links
- Dalapon in the Pesticide Properties DataBase (PPDB)
- Dalapon-calcium in the Pesticide Properties Database (PPDB)
- Dalapon-magnesium in the Pesticide Properties Database (PPDB)
- Dalapon-sodium in the Pesticide Properties Database (PPDB)
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