Comparative efficacy of natural and nano‐sized diatomaceous earth against American cockroach, Periplaneta americana , for sustainable control

Diatomaceous earth (DE) is gaining recognition as a sustainable, eco‐friendly insecticidal agent, but its effectiveness is often limited by particle size and surface features. Nanotechnology may provide a promising way to overcome these limitations. Therefore, this study aimed to compare the insecticidal effects of natural and nano‐sized DE against the American cockroach, Periplaneta americana . Natural DE was transformed into nanoform using the ball milling technique. Adults were exposed to five concentrations of each formulation, and mortality was measured. The lethal concentrations (LC 50 ) were determined, and biochemical, histological and ultrastructural analyses were performed to understand the underlying mechanisms. The results showed that both forms of DE caused significant mortality; however, nano‐sized DE demonstrated notably higher effectiveness, reaching 100% mortality at 72 h and exhibiting lower LC 50 values than the natural form. Biochemical tests revealed that both DE and nano‐sized DE significantly reduced total lipids and total antioxidant capacity, with nano‐sized DE having a stronger effect. In contrast, lipid peroxidation, indicated by malondialdehyde levels, was significantly increased, especially in the nano‐DE group. Ultrastructural examinations revealed marked thickening and disorganization of the endocuticle, partial depletion of lipid‐rich layers and disruption of epidermal cells. Remarkably, nano‐sized DE particles were observed within the cuticular matrix and interacted with lipids, indicating enhanced adhesion and mechanical disruption. In summary, these findings show that nano‐sized formulation significantly boosts the insecticidal effect of DE against P. americana . The study offers valuable insights into how nanotechnology can optimize DE‐based pest control strategies, promoting sustainable and environmentally safe management methods.