Insecticidal activity of crude extracts of four plants and their Ag Nano liquids against Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

Abstract

A good quantity of global agricultural production is being devastated due to insect pests which need serious attention by the agricultural scientists and policy makers. The sole dependence on agrochemicals has increased over the past decades. However, adoption of botanical insecticides is gaining momentum as an ecofriendly alternative to the hazardous chemical pesticides. Applications of bionanoparticles are highly effective and may limit the risk of synthetic pesticide usage. Leaf dip and topical application toxicity bioassay were carried out to investigate the biological effects of aqueous leave extracts of Annona squamosa, Justicia adathoda, Ipomea carnea and Pongamia glabura at different concentrations (1.25, 2.5, 5 and 10%) against first, second, third nymphal instars and adult of Phenacoccus solenopsis (Hemiptera: Pseudococcidae). The result suggest that the aqueous leaf extract of P. glabura (LC50 = 9.673%) showed more impact after 144 hrs of exposure followed by J. adathoda, I.carnea and A. squamosa in leaf dip toxicity bioassay. In the topical application, P. glabura (LC50 = 1.042%) recorded the highest insecticidal activity followed by other three tested plants. The AgNP’s of P. glabura-AgNP’s showed highest impacts (LC50 = 4.750%) than other three tested nanoparticles i.e., I.carnea-AgNP’s, J. adathoda-AgNP’s, A. squamosa-AgNP’s in addition to Vijay neem, respectively. From these experiments, it is evident that the P. glabura-AgNP’s and J.adathoda-AgNP’s possess more insecticidal activity and hence these products could be used for P. solenopsis management.