Rapid insecticide resistance bioassays for three major urban insects in Taiwan.

BACKGROUND: Taiwan's warm and humid climate and dense population provide a suitable environment for the breeding of pests. The three major urban insects in Taiwan are house flies, cockroaches, and mosquitoes. In cases where a disease outbreak or high pest density necessitates chemical control, selecting the most effective insecticide is crucial. The resistance of pests to the selected environmental insecticide must be rapidly assessed to achieve effective chemical control and reduce environmental pollution. METHODS: In this study, we evaluated the resistance of various pests, namely, house flies (Musca domestica L.), cockroaches (Blattella germanica L. and Periplaneta americana), and mosquitoes (Aedes aegypti and Ae. albopictus) against 10 commonly used insecticides. Rapid insecticide resistance bioassays were performed using discriminating doses or concentrations of the active ingredients of insecticides. RESULTS: Five field strains of M. domestica (L.) are resistant to all 10 commonly used insecticides and exhibit cross- and multiple resistance to four types of pyrethroids and three types of organophosphates, propoxur, fipronil, and imidacloprid. None of the five field strains of P. americana are resistant to any of the tested insecticides, and only one strain of B. germanica (L.) is resistant to permethrin. One strain of Ae. albopictus is resistant to pirimiphos-methyl, whereas five strains of Ae. aegypti exhibit multiple resistance to pyrethroids, organophosphates, and other insecticides. CONCLUSIONS: In the event of a disease outbreak or high pest density, rapid insecticide resistance bioassays may be performed using discriminating doses or concentrations to achieve precise and effective chemical control, reduce environmental pollution, and increase control efficacy.

Modified distributed Bragg reflector for protecting organic light-emitting diode displays against ultraviolet light.

Sunlight/UV (ultraviolet)-induced degradation is still a critical issue for outdoor applications of organic light-emitting diode (OLED) displays. Therefore, effective UV-blocking structures that can prevent OLED displays from sunlight/UV degradation and still keep the OLED panels' display performance is necessary. In this report, modified distributed Bragg reflector (DBR) structures having UV-absorbing dielectric materials and adjusted layer/pair thicknesses were developed to realize effective UV blocking properties (nearly 0% transmittance below 400 nm), constantly high transmittance like glass in the visible range (∼92%) required for display applications, and sharp transition in transmission between the UV and the visible ranges. Furthermore, under the rigorous IEC 60068-2-5 solar test condition, it was verified that the developed modified, UV-blocking DBR can effectively enhance the OLED panel's resistance against UV/solar-induced degradation, effectively reducing voltage shifts of OLED devices after repeated solar test cycles.