In vitro Assessment of the Insecticidal Activity of Nerium oleander Extract against German Cockroaches (Blattella germanica)

Abstract

Background: German cockroaches are the most common cockroach species in the world. Although German cockroach infestations occur in many human-inhabited spaces, they are most commonly associated with restaurants, food processing facilities, hotels, nursing homes. It’s also carried viruses, protozoa and infectious bacteria on the outside and inside of body surfaces and play a role in causing dizziness, asthma and nausea reactions in people. So, Blattella germanica is considered as an important medical and economic. Methods: This study aimed to evaluate the efficacy of Nerium oleander extract against cockroaches and inhibition hatching eggs in vitro using a dipping method test. Two graduated concentrations of extract (50 and 100 mg/ml) were tested at different periods and changes over time in the viability of cockroaches were registered for (1 and 2 hours) and in relation to Inhibition hatching eggs after 30 days. Distilled water and cypermethrin (0.1%) were used as negative and positive control, respectively. A chemical assay was performed by FT-IR to investigate the presence of several anticipated active chemical compounds in Nerium oleander leaf extract. Result: The analysis of phytochemicals by FT-IR for alcoholic extracts of Nerium oleander extracts revealed the presence of 12 effective chemical ingredients such as carbohydrates, alkaloids, flavonoids, glycosides and tannins. The results showed that the extract had high efficacy in killing Cockroaches that were exposed to a high concentration of extract (100 mg/mL), the mortality rate was (90 and 100%), compared to the (cypermethrin 0.1%), the mortality rate was (70 and 100%) during the periods (1 and 2 hr) respectively. While the eggs cockroaches that were exposed to concentration of extract (100 mg/mL) and positive control (cypermethrin 0.1%) the hatching rate was (60 and 60%) after 30 days period respectively. While the negative control (without treated) was the hatching eggs cockroaches rate is (100%) during that period.