Snap bean pests and diseases in Sumapaz, Colombia: their present status and implications

Initial studies on snap bean production in Sumapaz, Colombia, indicated excessive use of pesticides in the region. A more in- depth investigation of how chemicals are used to control insects and diseases, and the economic and agroecological implications was thus initiated in 1989. It was found that reliance on pesticides was largely related to the disease susceptibility of the most popular variety grown, Lago Azul. Of the farmers surveyed, 90 percent sprayed their crops once a week with a mixture of 1-2 pesticides, 2-3 fungicides and a foliar fertilizer. Indiscriminate application of insecticides appears to have little, if any, effect on yields, but a destructive effect on natural enemies of leafminer. So far, though, snap beans tested for chemical residues from the region have shown no appreciable levels of contamination. (AS)