Oral toxicity of various crude extracts against nymph and adult stages of American cockroach, (Dictyoptera: Blattodea).

exhibits insecticidal resistance against various pests and insect vectors. However, insecticidal activity of roots has not been tested for some insect vectors, including the American cockroach, . The synanthropic insect is a reservoir of pathogenic and non-pathogenic microorganisms and a cause of infectious diseases and cockroach allergy. This important vector transmits microorganisms to animals and humans to cause vector-borne diseases. This research involved detection of the nymphicidal and adulticidal activities of root extracts against through oral administration. The effects of hexane, dichloromethane, ethanol, and water crude extracts were tested on final instar nymphs and adult . After ingested bait containing hexane and dichloromethane crude extracts, signs of toxicity occurred, such as hind leg shaking, whole-body tremor, immobility, abdomen swelling, and death. At 48 h, the nymphs and adult that ingested dichloromethane crude extract-containing bait showed corrected mortality of 65%-100% and 20%-100%, respectively. Whereas none of the nymphs and adult that ingested the water crude extract-containing bait died (0% corrected mortality). When we dissected alimentary canals of the dead that had ingested dichloromethane and hexane crude extract-containing baits, the foreguts were found to be swollen. TLC analysis showed the dichloromethane and hexane crude extracts contained the alkaloid didehydrostemofoline and unknown fluorescent substances. Phytochemicals from crude extracts were detected in extracts of dissected alimentary canals using thin-layer chromatography, and didehydrostemofoline alkaloid and unknown fluorescent substances were found in cockroaches that ingested dichloromethane- and hexane-containing baits. The cause of death of may be attributed to alkaloids and synergistic effects of other substances in root extract. Mechanisms of action might include several pathways involved in nervous system function. Thus, dichloromethane and hexane crude extracts can be developed as alternative active ingredients in a natural insecticide for cockroach control.