III CHANGES IN RESISTANCE LEVELS IN POPULATION OF GERMAN COCKROACH BLATELLA GERMANICA (L.) WITHOUT PRESSURE TO SELECT INSECTICIDES FOR MORE THAN TEN YEARS

• Main Author: Van Dini, Putik
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/65971
• Institution: Institut Teknologi Bandung

The German cockroach, Blatella germanica L (Dictyoptera: Blattelidae), is an insect that is often considered a residential pest. It is usually controlled by using insecticides. However, the repeated use of insecticides has led to the emergence of resistance. The existence of such resistance can result in the use of insecticides being ineffective. This study was conducted to study whether several German cockroach strains that had previously been reported to be resistant in 2011 and 2013 were then maintained in the laboratory for more than ten years without insecticide selection pressure experiencing changes in resistance levels. Therefore, a topical bioassay was carried out to measure the resistance levels of deltamethrin, propoxur, fipronil, and permethrin. In general, the results showed the resistance level of the German cockroach, Blatella germanica which was initially resistant to several insecticides. After being reared for more than ten years in the laboratory without any insecticide treatment, the resistance level decreased significantly; even some became susceptible strains. For example, the MDN2 strain, was initially classified as extremely resistant to deltamethrin (RR50: 1072, changed to a susceptible one (RR50: 1 ). The same with the ACH2 strain, which initially had a high resistance to propoxur (RR50: 48.64), and fipronil (RR50: 12.21) became susceptible. The decrease in the resistance levels was possible due to a reduction in the frequency of resistant genes and the high fitness cost of resistant German cockroaches.