Behavioral Responses Of The German Cockroach, Blattella Germanica (L.) (Dictyoptera: Blattellidae) Towards Toxic Baits
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Date
2009-11
Authors
Quah, Lay Tyng
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
This study focuses on the comparative performance of selected insecticide gel baits and the association between the feeding behaviour of German cockroaches, Blattella germanica (L.), and the toxicity of the baits. An arena test was conducted to evaluate the effectiveness of gel baits on three life stages of the German cockroach: adult males, adult females, and intermediate nymphs. A total of five commercial gel baits were tested and their effectiveness was evaluated by comparing their LT50 and LT95 values. The sequence of effectiveness of the baits from the least to greatest LT50 value (p = 0.05) was: fipronil = indoxacarb > imidacloprid > abamectin > hydramethylnon. However, the LT95 values were slightly different: fipronil = indoxacarb > abamectin > hydromethylnon > imidacloprid. In addition, nymphs were less vulnerable than adults. In terms of secondary transmission, the performance of the five gel baits were absolutely affected by the presence of an alternative food (p = 0.05) because the LT50 and LT95 value without an alternative food were significantly lower (p < 0.05) than when an alternative food source was present along with the carcasses.. Further studies were conducted using fipronil and indoxacarb gel baits. The feeding response of adult males, adult non-gravid females, gravid females, late nymphs, intermediate nymphs, and early nymphs were studied. The two types of bait did not differ significantly (p > 0.05) in terms of feeding frequency and the amount of time that German cockroaches spent on the baits. The time taken for cockroaches to approach the gel bait and the time required for them to die after consuming the gel bait were also evaluated in this study. The initial response of the cockroaches to the baits and the killing effect of the baits were significantly (p < 0.05) affected by the association of the three main factors: types of gel bait, the number of baits placed, and differences in starvation level. When greater numbers of baits were used, German cockroaches were more likely to approach it (p < 0.05). German cockroaches reacted rapidly towards Maxforce Select® gel bait = Maxforce FC® gel bait > Avert® gel bait = Infiniti® gel bait = Advion® gel bait. In addition, the killing effects (i.e., time required to cause death) of these five insecticide gel baits from most effective to least effective were: Maxforce Select® (230.76 ± 3.57 minutes) < Advion® (323.21 ± 4.00 minutes) < Maxforce FC® (479.65 ± 9.25 minutes) < Avert® (540.39 ± 7.11 minutes) < Infinit® (2084.73 ± 23.71 minutes). An increase in the level of starvation of the German cockroach, fastened the time taken for cockroaches to access the baits (p < 0.05) and also enhanced its killing effect on German cockroaches (p < 0.05).
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Keywords
Insecticide gel baits and the association , between the feeding behaviour of German cockroaches