1. BACKGROUND

Summary

Since 2001, ARKEMA is developing DMDS in Europe, other Mediterranean countries and the USA. DMDS, one of the most important compounds of Allium, is a natural fumigant (Auger, J. and Charles, P., 2003). It can be used for soil disinfestation in shank and drip applications (pure product and 95% water emulsifiable concentrate).
Based on the available data, DMDS could be a viable replacement for Methyl Bromide (MB) and other fumigants (Auger, J.,2005). According to the results from previous and recent studies, DMDS is a broad-spectrum fumigant that has nematicide, fungicide, insecticide and herbicide effects (Arnault, I. et al., 2006; Coosemans, J., 2004). Studies on the DMDS demonstrated that it acts on mitochondrial respiration by blocking the cytochrome oxidase activity. Furthermore, its toxicological and eco-toxicological profile looks favourable.

Product characteristics

DMDS has a long history as an industrial chemical (sulphiding agent for catalysts in refineries and sulphur donor in petrochemical industry as coke inhibitor). DMDS is also a natural molecule found in plant tissue degradation and used as flavouring agent (JECFA n°564). DMDS has harmful acute toxicity, but it has not mutagenic, cytotoxic and teratogenic effects.

• Composition: dimethyl disulfide CH3-S-S-CH3
• CAS registered number: 624-92-0
• Appearance: yellow liquid, garlic smell
• Molecular weight: 94.2 g.mol-1
• Specific gravity / air: 3.3
• Boiling point: 109.8°C
• Flash point: 16°C
• Vapor pressure at 25°C: 38.7mm Hg
• Water solubility at 25°C: 3g.l-1
• Half life in air: 45 minutes
• Ozone Depleting Potential: 0
• Materials compatible with DMDS: Carbon steel, Stainless steel, Aluminium, Teflon, Kynar, Viton, Phenol-formaldehyde resin, Epoxy resin, Asbestos, Graphite, Glass, Kalrez. When DMDS is diluted into water DMDS is compatible with Rubber, Ethylene propylene, Polyethylene & silicone.

Measurements of biogenic sulphur natural emissions using trapping with gas-chromatographic analysis showed that in addition to H2S, other sulphur compounds such as DMDS are released into the atmosphere. Plants and micro-organisms play a central role in DMDS emissions in marine environments, coastal wetlands, and terrestrial ecosystems via rather well known pathways.

Formulation and application

DMDS can be applied through drip (95% emulsifiable concentrate) or shank application (pure product). Moreover DMDS may be combined with other soil fumigants as well as chloropicrin.
DMDS has been authorized in the US for larger scale grower trials under Experimental Use Permit n° 4581-EUP-1 (2007)
Experimental evaluations are underway in the Europe, Morocco, Turkey, Israel, South Africa, Argentina, Mexico & in the US

Good practices in implementation require adequate preparation of the soil (shredded and soft), with soil moisture between 30 and 70% of field capacity in the profile up to 20-30 cm deep, and temperature above 12°C.
DMDS diffuses quickly in soil followed by homogeneous gas concentration after 1 day.
It is recommended to reduce the chemical dissipation into the atmosphere using sealing techniques (e.g. plastic mulching, soil rolling, irrigation). Moreover, the Concentration Time (CT) factor of the chemical into the soil is higher when using virtually impermeable films (VIF). DMDS can be used as pre-plant fumigant and the period between the treatment and the transplant should last at least 14 days (minimum 7days fumigation under covering system + 7 days for dissipation before planting). A longer period under covering is required if the soil is wet and/or in cold soil conditions.

Broadcast or bed shank application

Applications by injection 15 to 30 cm depth around under plastic film or using sealing methods; the optimum depth depends of the pest (ex.: 30 cm for fungi, 25 cm for nematodes, 15 cm for weeds). To select application equipment which allows a good control of the injection depth and the best soil seal under existing conditions. DMDS formulation is pure DMDS (density 1.06).

Drip system application

Application must be done under mulched fields. Drip fumigation needs the availability of drip irrigation systems. The drip irrigation systems adopted for crop irrigation could be used: the use of drip irrigation systems needs an accurate drip irrigation rinsing. Drip application may be carried out with an average water volume of 20-30 l/m2. For example drip irrigation is carried out in broadcast or on beds mechanically made, each bed (70 cm width) is provided with 2 drip lines (17 mm diameter) equipped with water nozzle (flow rate 2.4 l/h)., placed on the soil surface, 30 cm spaced apart.

DMDS formulation: DMDS EC 95% (density 1.06).

2. RECOMMENDATIONS FOR THE KEY CROPS

As mentioned in the introduction, DMDS is a chemical that recently has been tested as soil fumigant. Researches are still in progress in many countries and the results obtained up to date are incomplete, although the tests conducted experienced good efficacy of the chemical (Pommier, J.J., 2007; Fritsch, J., 2002-2007, Lopez Aranda JM 2005).
In the tables below are indicated the rates and distribution techniques recommended for using DMDS in some key crops.

3. RECOMMENDATIONS FOR OTHER CROPS

Trials are under progress (recommended doses for testing 20 – 80g/m2 in straight or in combination with other fumigants) in following crops for nematodes, soil diseases & weeds control:

• Strawberries nurseries
• Peppers
• Lettuces
• Potatoes
• Ornamentals
• Orchards
• Grapes

4. LIMITATIONS

Due to the relevant dose differences shown between applications, the target of the fumigation has to be well known. Moreover, a potential limiting factor may be represented by characteristic garlic odour (Good fumigation practices are recommended).

5. REFERENCES

• Auger, J., Charles, P., 2003, Biogenic emission, biological origin and mode of action of DMDS a natural ubiquitous fumigant, Abstracts, Annual International Research Conference on Methyl Bromide alternatives and Emissions reductions, San Diego, USA 3-6 November 2003:138
• Charpentier, M., Arnaud, I., Diwo, S., Auger, J., Reverchon, S., 2003 ,Potentiel fongicide de composés soufrés issus des Allium pour l’étude d’une alternative au bromure de méthyle, Proceedings, AFPP 7ème Conférence Internationale sur les maladies des plantes, Tours, FRANCE 3-4-5 Décembre 2003
• Auger, J., 2005, Les disulfures, pesticides naturels : le cas du DMDS, Proceedings, AFPP 7ème Conférence Internationale sur les ravageurs en agriculture, Montpellier, FRANCE 26-27 Octobre 2005
• Arnault, I., Du Fretay, G., Vey, F., Tissier, A., Fleurance, C., Auger, J., 2006, Soil fumigation with Allium sulfur volatiles and allium byproducts, Proceedings, Second biofumigation conference, Moscow, USA 26-29 June 2006
• Charles, P.,2003, DMDS a new alternative for soil disinfestation, Abstracts, Annual International Research Conference on Methyl Bromide alternatives and Emissions reductions, San Diego, USA 3-6 November 2003:23
• Coosemans, J., 2004, Dimethyl disulphide (DMDS): a potential biopesticide against potato cyst nematodes and root-knot nematodes, Abstracts, XXVII ESN International Symposium, Roma, ITALY, 14-18 June 2004: 51
• Coosemans, J., 2004, Dimethyl disulphide (DMDS): a potential novel nematicide and soil desinfectant, Abstracts, 6th International Symposium on chemical and non-chemical soil and substrate disinfestation, Corfu, GREECE 4-8 October 2004: 23
• Fritsch, J., Baudry, A., Aubert, T., 2002, DMDS as a new potential alternative to methyl bromide for soil disinfestation, Proceedings, International Conference on alternatives to Methyl Bromide, Sevilla, SPAIN 5-8 March 2002: 321
• Fritsch, J., 2003, Le DMDS comme alternative potentielle au BM en désinfection des sols, Abstracts, Rencontres phytosanitaires Légumes & fraises CTIFL/SPV Nîmes, France, 22-23 January 2003
• Fritsch, J., 2004, DMDS as a new chemical potential alternative to MB in soil disinfestation in France, Abstracts, 6th International Symposium on chemical and non-chemical soil and substrate disinfestation, Corfu, GREECE 4-8 October 2004: 25
• Fritsch, J., 2007, Nouveaux fumigants et nouvelles techniques de désinfection des sols après le bromure de méthyle, Abstracts, Rencontres phytosanitaires Légumes & fraises CTIFL/SPV Bergerac, France, 30-31 January 2007
• Fritsch, J., 2007, Vers de nouveaux fumigants et nouvelles techniques en désinfection des sols, Abstracts, 4th international symposium APEFEL, Agadir, Morocco, 18-19 May 2007
• Garibaldi A., Baudino M., Minuto A., Gullino M.L. (2008) Effectiveness of fumigants and grafting against tomato brown root rot incited by Colletotrichum coccodes. In Press
• Heller, J.J., Sunder, Ph., Charles, P., 2007, DMDS a new alternative to existing fumigants on carrots, Abstracts, 32nd In ternational carrot conference,Arcachon, France 5-7 September 2007 Lopez Aranda JM & al, Les alternatives chimiques en Espagne. Le cas des fraises : pépinières et production, Proceedings, Rencontre technique : désinfecter les sols autrement. Perspective à court et à moyen terme, Nîmes, France, 7 Décembre 2004 (2004).
• Lopez Aranda, J.M., Santos, B.M., Gilreath, J.P., Miranda, L., Soria, C., Medina, J.J., 2005, Evolution of Methyl Bromide alternatives for strawberry in Florida and Spain, Abstracts, Annual International Research Conference on Methyl Bromide alternatives and Emissions reductions, San Diego, USA, October 31 November 3, 2005:5 Pommier JJ, Alternative au bromure de méthyle en désinfection des sols : le DMDS, espoirs en culture de fraisier, Abstracts, Rencontres phytosanitaires Légumes & fraises CTIFL/SPV Bergerac, France, 30-31 January 2007 (2007).
• Pommier, J.J., 2007, Alternative au bromure de méthyle en désinfection des sols : le DMDS, espoirs en culture de fraisier, Abstracts, Rencontres phytosanitaires Légumes & fraises CTIFL/SPV Bergerac, France, 30-31 January 2007 and 4th international symposium APEFEL, Agadir, Morocco, 18-19 May 2007

Authors

Auger J : Université François Rabelais, IRBI, Tours (France) auger@univ-tours.fr

Charles P: ARKEMA, GRL, Pau (France) patrick.charles@arkema.com

Coosemans J: Katholic University , Leuven (Belgium) jef.coosemans@agr.kuleuven.ac.be

Fritsch J: Ministry of Agriculture, LNDS, Bordeaux (France) jerome.fritsch@agriculture.gouv.fr

Garibaldi A.: University of Torino (Italy) angelo.garibaldi@unito.it

Heller JJ: UPL CEREXAGRI., Paris (France) jean-jacques.heller@uniphos.com

Lopez Aranda JM : CIFA, Malaga (Spain) josem.lopez.aranda@juntadeandalucia.es

Pommier JJ: HORTIS-CIREF, Périgueux (France) jjacques.pommier@hortis.fr

Contacts

www.arkema-inc.com

Downloads

DMDS / Dimethyl Disulfide

Writing Date : 2008-08-29
Latest update Date : 2008-08-29