December 1, 2004
Despite extensive and expensive research into methyl bromide alternatives over the past decade, there is no one product that is an acceptable alternative. Methyl bromide was applied to 99% of the pepper acreage, 100% of the strawberry acreage, and 77% of the tomato acreage in Florida in 2002. Cucurbits, either cucumber or squash, are planted directly after these crops and so are indirectly dependant upon methyl bromide. Over the same time period, the areas of inexpensive, low-energy, passive-ventilated, plastic-covered greenhouses have expanded dramatically worldwide. For example, the Mediterranean Basin is estimated to have 100,000 ha, and the area in Mexico is increasing by 30% annually. The greenhouse production area in the U.S. is also expanding rapidly and is estimated at 1,000 ha (~2,500 acres). Greenhouse production offers several advantages including up to 10-fold increased yields, improved crop quality, recycling of water and nutrients, and the potential to grow pesticide-free produce. Soilless media eliminates the need for methyl bromide as it avoids weeds, soil-borne pathogens or plant parasitic nematodes. Imported, quality greenhouse produce from several countries including Mexico, Canada, and Spain is sold at a premium over U.S. field-grown produce. The Protected Agriculture Project (www.hos.ufl.edu/ProtectedAg) at the University of Florida adapts available greenhouse technology for Florida conditions and has developed extensive information for the production of most of the major greenhouse vegetable crops.