SummaryThe powder and ethanol extract of Tithonia diversifolia leaves were tested for their efficacy at five different concentrations (0.0%, 0.5%, 1.0%, 1.5% and 2.0%) on bruchid mortality, oviposition and adult emergence of cowpea seed beetle Callosobruchus maculatus at ambient tropical storage conditions of temperature and relative humidity. Results showed that the leaf extract had a higher bioactivity on oviposition, adult emergence and mortality of C. maculatus. The mean number of eggs laid on seeds treated with extract was reduced from 20.7 in the solvent‐treated to 4.7 at 2%Tithonia extract concentration while adult emergence reduced from a mean of 92.2 in the solvent‐treated seeds to 72.2 at 2.0% extract treatment. Mortality was 100% at higher concentrations of 3%, 4% and 5% within 24 h of extract application but at lower concentrations mortality was 73.3% and 93.3% at 1% and 2%, respectively after 24 h. Fourty‐eight hours after application, 100% mortality of adult C. maculatus was obtained at all concentrations. The mean number of eggs laid was reduced from 41.3 in the untreated to 17.3 at 2.0% powder concentration while adult emergence dropped from 98.5% in the control to 74.2% at the highest powder concentration. The powder was effective at higher concentrations and longer exposure time. At 3%, 4% and 5%, 63–75% mortalities occurred within 24 h of application while at 48 h, mortality was 76–98% at 3–5% powder application rates. The results of this study revealed T. diversifolia as a potential candidate for bioinsecticide preparations because of antiovipositional, ovicidal and knockdown properties of its products, which have some volatile components.

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Background: Mosquitoes are known to be notorious for their ability to constitute a nuisance as well as transmit disease-causing organisms (pathogens) to hosts. This study was aimed to determine the species distribution, abundance, and diversity of mosquitoes in Akure South Local Government Area, Ondo State, Nigeria. Results: A total number of 100 sites (20 sites from each location) were randomly sampled in the five locations (Alagbaka, FUTA, Oja-Oba, Ondo road, and Seebi). These larvae were identified to species level using × 20 magnification of a dissecting microscope and identification keys. Thirteen species of mosquitoes including 5 Aedes species, 6 Culex species, and a species of Anopheles and Toxorhynchites belonging to four genera were recorded. The abundance of the four mosquito genera varied significantly (p < 0.05) with Culex having the highest abundance (2151) and Toxorhynchites having the lowest abundance (23). Also, the distribution and abundance of the mosquito species varied significantly (p < 0.05) with Culex andersoni being the most abundant species encountered (709) and Culex striatipes being the least abundant (8). The favorable physico-chemical parameters that favor breeding include pH range of 7.14-7.30, temperature range of 27.3-29°C, electrical conductivity range of 65.6-98.0 μs, and dissolved oxygen range of 2.43-3.84 mg/l. Also, FUTA (1400) and Oja-Oba (994) had higher mosquito abundance than other locations (Alagbaka-124, Seebi-198, and Ondo road-224). Conclusions: The persistent occurrence of Aedes, Culex, and Anopheles species pose a serious epidemiological concern to the inhabitants of Akure South Local Government Area. Therefore, public enlightenment on vector control is of paramount importance.

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