Larvicidal and Pupicidal Potential of Aframomum melegueta K. Schum Extracts Against Mosquito, Anopheles Species

Abstract

The use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. The use of herbal products is one of the best alternatives for mosquito control. The present study was to screen the larvicidal and pupicidal potential of Afromomum melegueta leaf and seed extracts against larvae and pupae of Anopheles species in the laboratory at ambient temperature of 28±2^oC and relative humidity of 75±5%. The extracts of the plant parts were extracted with methanol and they were prepared at concentrations of 0.1, 0.2, 0.3, 0.4 and 0.5. The larvae and pupae of Anopheles species were exposed to these concentrations of the plant extracts for 24 hours and mortality was recorded. At all levels of concentrations, larval and pupal mortalities of this insect increased with increase in the concentrations irrespective of the type of plant parts extract used. However, seed extract of A. melegueta showed more insecticidal effect on both the larvae and pupae of Anopheles species at rate 0.1% but its effect was not significantly (p>0.05) different from extract of A. melegueta at 0.2%, 0.3%, 0.4% to 0.5% concentrations. It was observed that the larvae of Anopheles species were more susceptible to the extracts of the plant parts tested. All the plant parts extracts used in this work showed high effectiveness to larval and pupal mortalities and could therefore be used to reduce occurrence of malaria incidence. Their adoption might prove to be an effective and eco-friendly herbal insecticides in ensuring maximum safety in any ecological condition.