摘要
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The phase-out of methyl bromide (MB), as required by the Montreal Protocol and by pesticide regulations in some countries, has led to substantial changes in production practices in the horticultural sectors that relied on this fum...
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The phase-out of methyl bromide (MB), as required by the Montreal Protocol and by pesticide regulations in some countries, has led to substantial changes in production practices in the horticultural sectors that relied on this fumigant in the past, both in industrialised and developing countries. The major sectors that have used MB for soil fumigation (pre-plant) in the past are cucurbits, tomatoes, strawberry fruit, cut flowers, peppers and eggplant, orchard replant, potatoes, tobacco seedbeds and other propagative materials. The global consumption of MB was reduced from about 63,460 tonnes to 10,000 tonnes in the decade from 1997 to 2008 (excluding quarantine uses). The remaining consumption in 2008 (excluding quarantine uses) in industrialised countries was about 8% of the 1991 baseline and 35% of the baseline in developing countries. Adoption of alternative technologies has occurred at varying rates in different countries and productive sectors, but typically a period of 2 to 3 years has been necessary to achieve their implementation. Replacement of MB has been achieved with chemical fumigants where registered (1,3-dichloropropene, chloropicrin, metham sodium, dazomet and more recently methyl iodide) and with non-chemical options (soil-less substrates, grafting, resistant varieties, biological controls, steam, solarization, biofumigation). Very often, the best results have been found when combining and integrating alternative techniques; this has usually required growers to change production approaches significantly, undertake additional investments, adapt technologies to specific circumstances and acquire relevant training. However, these changes are often offset by good yields and quality. At this stage, and although some hurdles remain, alternatives that have comparable efficacy to MB have been found for virtually all previous soils uses of MB. Adoption and outcomes of alternatives that are widely adopted, such as grafting in the vegetable sectors; substrate production in floriculture, vegetables and strawberries; solarization plus alternative fumigants; and addition of composts and organic amendments to increase organic matter content in soils, are discussed.
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