Deltamethrin-resistant German Cockroaches Are Less Sensitive to the Insect Repellents DEET and IR3535 than Non-resistant Individuals

MENGONI, SOFIA; RAUL ALZOGARAY

JOURNAL OF ECONOMIC ENTOMOLOGY

ENTOMOLOGICAL SOC AMER

Lugar: Lanham; Año: 2017 vol. 111 p. 836 - 843

0022-0493

The German cockroach, Blattella germanica (L.)  (Blattodea: Blattellidae), is a serious worldwide pest with a considerable economical and sanitary impact. It is mainly controlled by the application of synthetic insecticides, butrepeated use of these substances has promoted the appearance of resistance in cockroach populations throughout the world. The aim of this study was to compare the behavior of deltamethrin-susceptible (CIPEIN colony) anddeltamethrin-resistant (JUBA and VGBA colonies) first instar nymphs exposed to the repellents N,N-diethyl-3- methylbenzamide (DEET) and ethyl 3 [acetyl(butyl)amino]propanoate (IR3535). Firstly, the behavior of the nymphswas assessed in an experimental arena in the absence of repellents. The parameters Distance Traveled, Velocity, Mobility Time, and Time Spent (in each half of the arena) were quantified using an image analyser, and showedthat the behavior elicited by the three colonies was similar. After this, the behavior of the nymphs was quantified in an arena, half of which had been treated with repellent. The repellency of DEET increased as a linear function oflog concentration for the three colonies. DEET elicited repellency as from a concentration of 97.49 µg/cm2 for the CIPEIN and JUBA colonies and 194.98 µg/cm2for the VGBA colony. The repellency of IR3535 was weaker and started at a concentration of 389.96 µg/cm2 for the CIPEIN colony, 779.92 μg/cm2 for JUBA, and 1559.84 μg/cm2 for VGBA. Finally, nymphs were exposed to 3:1, 1:1, and 1:3 DEET:IR3535 mixtures, and a synergistic effect was observed only in the CIPEIN colony.