Fumigants are used to control soil-borne pests to obtain larger yields of high-quality horticultural products (Messenger and Braun, 2000). Methyl bromide has been the most widely used fumigant, with 68,424 t used worldwide in 1996. The United States uses almost half of world consumption of methyl bromide (MB), and 70% of that is used for soil fumigation (Ware and Whitacre, 2004). Atmospheric MB originates from oceanic emissions and anthropogenic sources, such as biomass burning, agricultural applications, leaded gasoline combustion, and structural fumigation. The relative contributions of anthropogenic and natural emissions to total atmospheric MB are not well known (Butler and Rodriguez, 1996). However, it was estimated that anthropogenic sources account for 20% to 50% (Singh and Kanakidou, 1993).
Methyl bromide research has been conducted extensively in high-value crops such as tobacco (Nicotiana tabacum), tomato (Lycopersicon esculentum), pepper (Capsicum annum), cucumber (Cucumis sativus), and strawberry (Fragaria ×ananassa) (Csinos et al., 2000; Fennimore et al., 2003; Gilreath et al., 2004). However, there has been limited research reported for MB alternatives in ornamentals (Carpenter et al., 2000; Schneider et al., 2003).
The manufacture and importation of MB was essentially phased out in developed countries for general agricultural uses in 2005, and developing countries have agreed to eliminate most chlorofluorocarbons (CFC) by Jan. 2010 (United Nations Development Programme, 2006). The MB phaseout will affect agricultural production adversely, especially where alternative fumigants are not available. For example, the ornamental and nursery industries may lose $129 million in California and $14 million in North Carolina, due to differences in yield and control costs between the alternatives and MB (Carpenter et al., 2000). Loss of MB will affect cut-flower and ornamental crop production adversely more than other industries because breeding programs focus primarily on plant aesthetic qualities and not on disease tolerance, often leaving crops susceptible to diseases (Sances, 2005).
Metham sodium, chloropicrin, 1,3-dichloropropene, and iodomethane are potential substitutes for MB in ornamental production. The objective of this study was to evaluate crop safety and weed control with pre-transplant applications of these fumigants on seven ornamental species.
Butler, J.H. & Rodriguez, J.M. 1996 Methyl bromide in the atmosphere 28 83 Bell C.H., Price N. & Chakrabarti B. The methyl bromide issue, Vol. 1. Wiley Chichester, England
Carpenter, J., Leonard, G. & Lori, L. 2000 The economic impact of the scheduled U.S. phaseout of methyl bromide Natl. Ctr. for Food and Agr. Policy Washington, D.C
Csinos, A.S., Johnson, W.C., Johnson, A.W., Sumner, D.R., McPherson, R.M. & Gitaitis, R.D. 1997 Alternative fumigants for methyl bromide in tobacco and pepper transplant production Crop Prot. 16 585 594
Csinos, A.S., Sumner, D.R., Johnson, W.C., Johnson, A.W., McPherson, R.M. & Dowler, C.C. 2000 Methyl bromide alternatives in tobacco, tomato and pepper transplant production Crop Prot. 19 39 49
Fennimore, S.A., Haar, M.J. & Ajwa, H.A. 2003 Weed control in strawberry provided by shank and drip-applied methyl bromide alternative fumigants HortScience 38 55 61
Gerik, J.S. 2005 Drip applied alternatives for floriculture production 27 Oct. 2006<http://www.mbao.org/2005/05Proceedings/105GerikJDripAppliedAlternativesforFloricultureProduction.pdf>
Gilreath, J.P., Noling, J.W. & Santos, B.M. 2004 Methyl bromide alternatives for bell pepper (Capsicum annum) and cucumber (Cucumis sativus) rotations Crop Prot. 23 347 351
Messenger, B. & Braun, A. 2000 Alternatives to methyl bromide for the control of soil-borne diseases and pests in California California Dept. of Pesticide Regulat., Fumigant Resource Ctr Sacramento
Sances, F.V. 2005 Ten years of methyl bromide alternatives research and development: Lessons learned 27 Oct. 2006<http://www.mbao.org/2005/05Proceedings/018SancesFmbao2005abstract8-31-05.pdf>
Schneider, S., Rosskopf, E.N., Leesch, J.G., Chellemi, D.O., Bull, C.T. & Mazzola, M. 2003 United States Department of Agriculture—Agricultural Research Service research on alternatives to methyl bromide: Pre-plant and post-harvest Pest Mgt. Sci. 59 814 826
Schneider, S., Trout, T., Gerik, J., Shrestha, A. & Rodriguez-Kabana, R. 2005 Methyl bromide alternatives for perennial crop field nurseries 27 Oct. 2006<http://www.mbao.org/2005/05Proceedings/041SchneiderSNurserypaperMBAO2005.pdf>
Shrestha, A., Browne, G.T., Lampinen, B.D., Schneider, S., Simon, L. & Trout, T. 2005 Weed populations in nurseries as affected by methyl bromide and alternative fumigants 27 Oct. 2006<http://www.mbao.org/2005/05Proceedings/046ShresthaAabstract_MB2005.pdf>
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United Nations Development Programme 2006 The Vienna Convention and the Montreal Protocol 31 Oct. 2006<http://www.undp.org/montrealprotocol/montreal_new1.htm>
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