Evaluation of Five Medicinal Plant Extracts onAphis craccivora(Hemiptera: Aphididae) and Its Predator,Chrysoperla carnea(Neuroptera: Chrysopidae) under Laboratory Conditions

Botanical insecticides that degrade rapidly are safer than persistent synthetic chemical insecticides, less harmful to the environment, decrease production costs and are not likely to cause insecticide resistance among pests. This study aimed to evaluate the effect of five different botanical extracts on the bean aphid,Aphis craccivoraand the 2nd larval instar of the green lacewing,Chrysoperla carneaunder laboratory conditions. Also, the flavonoids in the methanolic extracts of these tested plants were detected using HPLC analysis. The data from the HPLC analysis indicated that the tested plants differed in their flavonoid components. The total flavonoids were 869.4, 1125.6, 721.4, 1667.8 and 2025.9 mg/kg inPsiadia penninervia,Salvia officinalis,Ochradenus baccatus,Pulicaria crispaandEuryops arabicus, respectively. Moreover, there were many variations among these plants in the amount of each compound. The lethal concentration (LC50) value ofP. penninerviaextract on aphids was the lowest among all of the plants (128.546 mu g/mL) followed byO. baccatus(626.461 mu g/mL). Also, the LC(50)value ofP. penninerviaextract on the 2nd larval instar ofC. carnea(232.095 mu g/mL) was significantly lower than those of all other four plant species extracts, while the other four plants did not show significant differences among them according to relative median potency analyses. Accordingly,O. baccatusextract had a strong effect on aphids and was safest for the predator. This finding suggests thatO. baccatuscould be exploited and further developed as an effective plant extract-based insecticide to be utilized in integrated pest management (IPM) programs againstA. craccivora.