Evaluation of a newly modified eight-chamber-olfactometer for attracting German cockroaches Blattella germanica (Dictyoptera: Blattellidae)

Attractive Toxic Bait (ATB) is a low risk practical method to cockroach control. This study aimed to evaluate efficacy of a newly modified eight-chamber-olfactometer for attractiveness experiments. Different stages of German cockroaches were exposed to carbohydrate-rich and protein-rich foods and their attractions were tested both at ambient conditions and in the modified olfactometer. In the latter method, cockroaches were released into the main chamber of olfactometer and their attraction to food compounds placed in test chambers were recorded as the number of captured cockroaches in test chambers. The direct attractiveness test was performed in plastic pans. Repellency of fipronil insecticide was performed with prepared bait powder using olfactometer. Data were subjected to analysis of variance with Tukey’s Test,P ≤ 0.05. Different notes should be considered when using introduced olfactometer like precision when opening the test chambers valves, the fan speed, placement of cardboard shelter in both test and main chambers, and initial starvation of cockroaches. Roasted peanut, banana and biscuits powder were the most attractive foods for cockroaches. The females significantly preferred roasted peanut and the males significantly preferred banana and roasted peanut. These results were similar to the results of direct attracted cockroaches. The cockroaches have repellency to fipronil but attractiveness of bait with 0.01% concentration was significantly higher than cockroach diet. Generally, three factors should be considered in formulation of ATB like un-repellency of the a.i, attractiveness of bait compositions, and palatability of bait texture. The olfactometer introduced in this study could be used by researchers to study cockroach behaviors.