Susceptibility of Malaysian Tropical Bed Bug Cimex hemipterus F. (Hemiptera: Cimicidae) Populations to Deltamethrin and Propoxur Insecticides - Zulaikha Zahran; Abdul Hafiz Ab Majid (Tropical Life Sciences Research, 2019)
Bed bugs were collected across Peninsular Malaysia to investigate their resistance to two types of insecticide classes, pyrethroid and carbamate. In this study, commercially-available deltamethrin and propoxur were used to test the resistance status of tropical bed bug, Cimex hemipterus in Malaysia. Their resistance status was evaluated using insecticide-impregnated papers, a bioassay method recommended by the World Health Organization (WHO). Ten adult bed bugs in each population were placed inside the tubes with papers impregnated with 0.05% deltamethrin and 0.1% propoxur. At first, the bugs were exposed for 24 h, then, the exposure period was extended to 14 days. The bioassay was performed in triplicates. The highest resistance level was exhibited by the AR population with a lethal time value (LT50) of 466.119 h in the deltamethrin-containing tube. In contrast, propoxur was highly effective against the IP population due to its lethal time value (LT50 = 153.032 h) was the lowest. A significant difference (p < 0.005) was found between insecticide classes and bed bug populations. Mean mortality among AR, SW, HM, PY and PC populations showed a significant difference when exposed to deltamethrin. In conclusion, propoxur showed high efficacy in controlling bed bug populations. However, its efficacy was only at particular places. Meanwhile, a treatment using deltamethrin should be avoided by pest control professionals due to its low efficacy. Pepijat telah dikumpul dari seluruh Semenanjung Malaysia untuk melihat tahap kerintangan terhadap dua kelas racun serangga, piretroid dan karbamat. Dalam kajian ini, deltamethrin dan propoxur yang tersedia secara komersial digunakan untuk menguji status kerintangan pepijat tropika, Cimex hemipterus di Malaysia. Status kerintangan mereka dinilai dengan menggunakan kertas yang diresapi racun serangga, suatu kaedah bioesei yang disyorkan oleh Pertubuhan Kesihatan Sedunia (WHO). Sepuluh pepijat dewasa dalam setiap populasi diletakkan di dalam setiap tiub dengan kertas yang diresapi 0.05% deltamethrin dan 0.1% propoxur. Pada mulanya, pepijat terdedah selama 24 jam, kemudian tempoh pendedahan dilanjutkan hingga 14 hari. Bioesei dilakukan dalam triplikat. Tahap kerintangan tertinggi dipamerkan oleh populasi AR dengan nilai masa maut (LT50) sebanyak 466.119 j di dalam tiub yang mengandungi deltametrin. Sebaliknya, propoxur sangat berkesan terhadap populasi IP (Ipoh) kerana nilai masa maut yang paling rendah, (LT50 = 153.032 j). Perbezaan yang signifikan (p < 0.005) didapati antara kelas racun serangga dan populasi pepijat. Purata kematian di kalangan populasi AR, SW, HM, PY, dan PC menunjukkan perbezaan yang signifikan apabila terdedah kepada deltametrin. Sebagai kesimpulan, propoxur menunjukkan keberkesanan yang tinggi dalam mengawal populasi pepijat. Walau bagaimanapun, keberkesanannya hanya di tempat tertentu. Sementara itu, rawatan menggunakan deltamethrin harus dielakkan oleh profesional kawalan perosak kerana keberkesanannya yang rendah.