REVIEW OF USE OF ALTERNATIVES TO METHYL BROMIDE FOR HORTICULTURAL CROPS IN ASIA

Methyl bromide is a broad spectrum pesticide, principally used as a fumigant. On soil, it is used as a pre-plant soil fumigant in locations where a broad complex of soil-borne pests limit the production of certain crops, particularly when they are repeatedly grown on the same land. In SE Asia and the Pacific, the use of methyl bromide as a soil sterilant is only about 6 % of all methyl bromide used (UNDP, 1995). Alternative methods to control soil pests are widespread. Aware of the negative side effects of pesticides, alternative soil pest control practices with reduced chemical inputs are being suggested. Soil pest control practices include biological control by means of natural enemies and integrated methods, such as integrated pest management (IPM) or integrated crop management (ICM). This paper documents a number of cases of alternative soil pest control methods with reduced chemical inputs in commercial use for horticultural crops in Asia. In addition, alternatives that have been found effective in field and/or greenhouse trials are reviewed. Cases of alternative soil pest control methods used commercially for horticultural crops on modem as well as traditional farms in Asia are listed in Table 1. The methods range from relatively new techniques, such as substrates and solarisation, to improved methods of traditional techniques, such as composting. There is now greater appreciation and respect for low-input, traditional agricultural systems, and the methods that are employed by traditional farmers are recognised as often being more efficient and logical than previously thought. In fact, to manage nematodes, integrated systems are being developed that incorporate or consider many alternative small-scale farmer practices (Bridge, 1996)