Synergists action of piperonyl butoxide and S,S,S-tributyl phosphorotrithioate on toxicity of carbamate insecticides against Blattella germanica

Objective: To determine the synergists action of piperonyl butoxide(PBO) and S,S,Stributyl phosphorotrithioate(DEF) on toxicity of carbamate insecticides against Blattella germanica in Tehran city.Methods: In the current study, German cockroach strains were collected from several hospitals and dormitories in Tehran.At the beginning, different concentrations of bendiocarb and carbaryl(insecticides belong to carbamate group) were determined by surface contact on a susceptible strain.Then, the level of susceptibility and type of resistance mechanisms in the collected strains from contaminated sites to the aforementioned insecticides were studied by using PBO and DEF synergists with different insecticide ratios to synergist(1:0, 1:1, 1:2, 1:3).Results: The DEF synergist along with bendiocarb and carbaryl completely eliminated the resistance in all strains but PBO did not completely eliminate the resistance in the strains of Mofid, Alvand, Valiasr hospitals and Shariati dormitory.Generally, the impact of DEF was observed in the removing resistance more than PBO.Conclusions: In most of these strains, resistance to bendiocarb and carbaryl is completely eliminated by DEF, showing a very high role of estraze enzymes in resistance to bendiocarb and carbaryl.But in most strains PBO does not remove the resistance because other mechanisms, such as reduced cuticle penetration and insensitivity to the acetylcholine esterase enzyme, may be involved.

Wild chive oil is an extremely effective larvicide against malaria mosquito vector Anopheles stephensi

Objective: To assess the chemical composition and mosquito larvicidal potentials of essential oil of wild chive(Allium schoenoprasum L.) against Anopheles stephensi.Methods: In the search for an environmentally safer alternative mosquitoes control, the larvicidal efficacy of essential oil obtained from the leaves of Allium schoenoprasum L. against Anopheles stephensi was determined. The composition of chive essential oil was analyzed by gas chromatography–mass spectrometry. Results: In toxicity assays, the essential oil demonstrated substantial larvicidal activity against larvae of Anopheles stephensi with LC_(50) and LC_(90) values of 2.60, and 7.31 ppm after 24 h of exposure, respectively. Gas chromatography–mass spectrometry analysis of chive essential oil identified 35 components representing more than 97.31% of the total essential oil. The main constituents were sulfur compounds, including diallyl trisulfide(13.72%), 2-ethyl[1,3]dithiane(8.93%), allyl methyl trisulfide(8.77%), and trimethylene trisulfide(6.64%), respectively. Conclusions: This study demonstrated that wild chive essential oil has a rich source of eco-friendly bioactive compounds for use as a mosquito larvicide. The main reason for its extraordinary properties may be related to the high percentage of sulfur compounds.

Diversity of Phlebotomine sand flies(Diptera: Psychodidae) in mountainous and plain areas of an endemic focus of anthroponotic cutaneous leishmaniasis in Iran

Objective: To determine the diversity of sand flies in different biotopes of mountainous and plain areas of Bam County as the most infected focus of anthroponotic cutaneous leishmaniasis in southeast Iran, and synanthropic index of Phlebotomus sergenti Parrot, and Phlebotomus papatasi Scopoli as the main vectors of cutaneous leishmaniasis in Iran.Methods: Sand flies were captured once a month using sticky traps in domestic, peri-domestic, agricultural, and sylvatic biotopes in the plain and mountainous areas. Alpha diversity indices, including richness, evenness, Shannon-Wiener;beta diversity indices(Jaccard’s and Sorensen’s similarity indices) and synanthropic index were calculated. Results: A total of 2 664 specimens of 9 sand fly species were collected from mountainous(47%) and plain(53%) areas. Species richness, species evenness, and Shannon-Wiener indices were obtained as 9, 0.637, and 1.399, respectively in the mountainous area. Phlebotomus sergenti and Phlebotomus papatasi were constant species with the synanthropic index of-18.463 and-29.412, respectively. In addition, species richness, species evenness, and Shannon-Wiener indices were 4, 0.690, and 0.956, respectively in the plain area. Phlebotomus sergenti and Phlebotomus papatasi were dominant species with the synanthropic index of +9.695 and +36.207, respectively. Similarity indices were low among different biotopes of plain and mountainous areas.Conclusions: A basic knowledge about the diversity of sand flies in various biotopes is essential to design sound control programs. Biodiversity and synanthropic indices of sand flies are different in plain and mountainous areas due to the difference in biotic and abiotic factors between the two areas.