Economic, environmental, and natural resource benefits of plastic sheltersin vegetable production in a humid tropical environment

This paper reports the effectiveness of plastic shelters in overcoming soil -related and biotic constraints to vegetable production in Belize, Central America, where rainy-season tomatoes and sweet peppers are almost totally d estroyed by geminiviruses. Use of pesticides is rampant, while rapid declin e in soil productivity induces farmers to abandon previously used lands aci d clear new lands from virgin forests. We postulated that plants growing in the open-field environment are infected early by the soil-borne pathogens deposited on the plants from clouds of fine soil particles arising from the soil splash during high-intensity rainfall. The products of fungal and bac terial decay attract white flies (the vector for geminiviruses) and plants already weakened by the infection succumb easily to the viruses. A producti on system in which plant and soil surfaces are protected from direct rainfa ll using plastic shelters, was designed and field tested with tomatoes and sweet peppers. On average, plastic shelters increased tomato and sweet pepp er yields by 169% and 96%, respectively, without any use of pesticides. Wee d growth under the shelter was negligible, and plants maintained greenness and production well into the fourth month after transplanting. In contrast, open-field plots were infested with weeds, and plants were completely dest royed by the middle of the third month. The number of white flies visiting the plastic-shelter plants was only about 28% of that in the open-field. We conclude that total protection of soil and plant surfaces from rainfall is the most effective plant protection measure. The proposed system uses smal l land area on a continuous basis, provides stable production, requires lit tle or no plant protection chemicals, and raises Farmer income.