Eco-friendly Control of Urban Pests: Effects of Piper nigrum-Based Silver Nanoparticles on the Biology and Histology of the American Cockroach (Periplaneta americana)

Periplaneta americana is associated with public health hazard and economic burdens. This research evaluates the potential of black pepper, Piper nigrum, as a natural control agent on American cockroaches by assessing the repellent and toxic effects of its aqueous fruit extract and eco-friendly silver nanoparticles. Experimental setup for toxicity evaluation, which included control groups along with those tested with, black pepper extract and silver nanoparticles, each of which was sprayed for treating them to a 10 sec across spray application with a range of concentrations of 20, 40, 60, 80, and 100 ml/L. Findings revealed that the LC50 value of black pepper-based silver nanobioparticles from black pepper extract was lower in male cockroaches (41.82%) than females (51.88%) after spraying. Moreover, both agents elicited biochemical changes, especially increasing levels of lipase and protease, while reducing total protein and amylase content in the midgut. On the other hand, microscopic examination of the midgut showed notable changes, in males, the circular and longitudinal muscles were missing, and columnar cells displayed signs of erosion and morphological changes. In females, partial tissues exhibited regenerative nidi combined with condensed chromatin material. It can be concluded that silver nanoparticles had notably higher toxicity as compared to the aqueous extract, especially in male cockroaches. Furthermore, the biochemical and histological alterations further confirmed the disruptive impacts of these agents on cockroach physiology and raised the possibility of P. nigrum derived compounds that may be useful for sustainable mitigating P. americana invasions.