UBC Theses and Dissertations

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UBC Theses and Dissertations

The assessment of potential insecticidal plants for local use in rural highland Ecuador Robertson, Veronica


In rural highland Ecuador, the potato provides the basic source of calories and nutrients to the local population. The indiscriminate use of synthetic pesticides applied in its production is taking a heavy toll on those people it is meant to sustain. Pesticide poisoning is currently the second-leading cause of death in many of the intensely agricultural provinces of the country, while sub-lethal effects deteriorate the quality of life for up to two-thirds of those exposed to the chemicals. Tecia solanivora (Povolny), the Guatemalan potato moth, is presently the greatest threat to potato production in the Andes region from Venezuela to Ecuador. This pest devastates production yields both in the field and in stores, with losses frequently exceeding 50%. The damage is caused by larvae burrowing into the tuber, excavating galleries and diminishing its quality. The pest has only recently become established in Ecuador, and there are currently no effective measures developed for its control. There is a clear need for the development of a non-toxic, efficacious measure of control for this insect pest in Ecuador. The major goal of this project was to identify botanical pesticides that can be produced locally for use against the Guatemalan potato moth as well as for other insect pests. Crude methanolic extracts of five local botanicals, Marco (Ambrosia artemisioides), Matico (Eupatorium glutinosum), Mashua (Tropaeolum tuberosum), Pumin, (Hyptis pectinata), and Santa Maria (Tanacetum cinerariaefolium), were screened for activity against the potato tuber moth, Phthorimaea operculella, and the cabbage looper, Trichoplusia ni. Extracts of Matico and Mashua were the most effective in controlling the potato tuber moth, although each botanical studied warrants further investigation as a component in an integrated pest management system. The efficacy of the five plants studied was highly variable in controlling the cabbage looper, although Pumin performed best overall.

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