Ethnobotanical study of plants used for traditional control of mosquitoes and other arthropod pests in the Ghibe valley, southwest Ethiopia.

Background: Medicinal plants have been used in the traditional healthcare system of Ethiopia, including controlling human biting mosquitoes. However, documented knowledge on such aspects remains scarce. In this study, plants used in the traditional control of mosquitoes and other arthropod vectors with the local knowledge and method of applications in the Ghibe valley of southwest Ethiopia were documented.

Methods: Semi-structured interviews were used to collect ethnobotanical data between March and October 2024. A total of 361 informants consisting of 77 key informants and 284 general informants were selected using purposive and systematic random sampling methods, respectively, in Enor, Deri Saja Zuria, Misha and Sekoru districts of southwest Ethiopia. Frequency of citation and simple preference ranking were employed to determine the most used insecticidal and insect repellent plants. Relative importance of multipurpose plants was assessed using direct matrix ranking exercises. Independent samples t-test and one-way ANOVA tests were conducted to compare knowledge of informants on insecticidal and insect repellent plants.

Results: A total of 53 plant species were used to control human biting insects. The most cited plant was Allium sativum L., (cited by 89%) followed by Croton macrostachyus Hochst. ex Delile (81%), Olea europaea subsp. cuspidata (Wall.G.Don) Cif. (77%), Coleus abyssinicus (Fresen.) A.J.Paton (69%; n = 361), Calpurnia aurea (Aiton) Benth. (63%), Juniperus procera Hochst. ex Endl. (63%), Echinops kebericho Mesfin (58%), Eucalyptus globulus Labill (56%), Melia azedarach L. (52%) and Phytolacca dodecandra L'Hér. (36%). The results of the current study showed that different informant groups had considerably different level of knowledge on traditional usage of insecticidal and insect repellent plants.

Conclusions: Plant species Eucalyptus globulus, Calpurnia aurea, Phytolacca dodecandra, Echinops kebericho, Croton macrostachyus and Juniperus procera were more frequently cited to be insecticides against human biting arthropods while Melia azedarach L., Olea europaea subsp. cuspidata, Coleus abyssinicus, Croton macrostachyus, Eucalyptus globulus, Lippia abyssinica (Otto & A. Dietr.) Cufod., and Juniperus procera were more frequently reported to be repellents. Some of these plants (Coleus abyssinicus, Croton macrostachyus and Echinops kebericho) have not yet been investigated in depth and thus require scientific evaluation for their efficacy as insecticides and or repellents against malaria-transmitting mosquitoes in Ethiopia.