Ethnobotanical study of pesticidal plants against human harmful insects in Central Burundi

Abstract

Human harmful insects include mosquitoes, lice, fleas, flea-biters, bedbugs, flies and fire ants. Developing countries, such as Burundi; are challenged in the access of chemical products to control these insects. The present study aims to control human harmful insects with pesticidal plants based on ethnobotanical knowledge of Burundians. A survey on pesticidal plants was carried out using a questionnaire on 250 participants in Gitega province, Central Burundi. The consensus index (CIs) was used to analyse the credibility of the information collected. Seventy five percent of participants recognized at least one pesticidal plant. The present study reveals 69 plant species divided into 35 families. The Asteraceae (8 species) and Euphorbiaceae (6 species) families were the most represented. Of all the plant species recorded, the most exploited part is the leaf (47% of species) and 50% of species are used without prior preparation, while 22% are roasted before use or administration. The local application is most used (for 46% of species). The most cited species are Tetradenia urticifolia (ICs: 0.60), Euphorbia tirucalli L (ICs: 0.10) and Tagetes minuta L (ICs: 0.06) repelling fire ants, Solanum incanum (ICs: 0.60) and Gymnanthemum amygdalinum (ICs: 0.12) treating the flea-bites. The present study showed a large number of pesticidal plants, some of them having a considerable potential in the control and treatment of these insects and their bites. The preferred use of the leaves leads to a promising valorisation with less impact on sustainable conservation of the reported plant species. The present study revealed the importance of pesticidal plants knowledge with an emphasis on plants against flea-bites and fire ants (31 and 23 species respectively). The results suggest that there is need for phytochemical studies aimed at the production of effective and affordable plant-based pesticides.