A newly modified eight-chamber-olfactometer for evaluation of attraction behavior of German cockroach (Blattella germanica)

Background: The German cockroach Blattella germanica (L.) is the most common domestic pests. Many efforts have been undertaken to find the least toxic formulations to control cockroaches. In this regard, the highly effective method, Attractive Toxic Bait (ATB), has created a revolution. Three main characteristics of ATB formulations include non-repellency of active ingredients, attractiveness of baits compositions and palatability of baits textures.Objectives: The aims of this study were to design a new eight-chamber-olfactometer to be used to test the repellency of Fipronil insecticide against the pest.Materials and Methods: The colony of German cockroaches was established and reared in the Entomology Laboratory of Yazd Science and Technology Park at 28±5ºC, 50±5% RH and 12:12 L:D. A new eight-chamber apparatus was constructed from polystyrene and Plexiglas materials so that to contain a main release chamber and eight small compartments as test chambers. The repellency of four logarithmic concentrations of fipronil including 0.01%, 0.02%, 0.04% and 0.08% was tested as prepared powder baits using the olfactometer. The tests were performed by putting 4 bait concentrations, a positive control (bait without insecticide), a negative control (chambers without any bait) and cockroach diet into test chambers. Data were subjected to analysis of variance with Tukey’s Test, P≤0.05. Care was taken when opening the test chambers valves, controlling the fan speed, placement of cardboard shelter in both test and main chambers, and observing an initial starvation of cockroaches.Results: The cockroaches showed repellency to fipronil at different concentrations. However, attractiveness of the bait mixed with 0.01% fipronil was significantly higher than cockroach diet. This means bait with 0.01% Fipronil could be as attractive as the remains of food compounds in the field conditions.Conclusion: The attractiveness of commercial toxic bait can affect its efficiency for controlling of German cockroach. Fipronil as a highly effective insecticide used in Goliath® and Maxforce® baits, can kill German cockroaches in Nano-gram quantities. We are introducing a new apparatus that it is suitable to determine attractiveness of various compounds like foods, insecticides and commercial baits and other cockroach behaviors without using camera or any video check system

کلیدواژه ها:

German Cockroach ، Olfactometer ، Fipronil ، Repellency