Evaluation of secondary killing effect of Imidacloprid Gel Baits to control Blattella germanica (Linné 1767) (Blattaria: Blattellidae)

Blattella germanica (L.) (Blattodea: Blattellidae) is one of the major household pests worldwide, commonly named German cockroach. Application of gel baits is one of the most efficient management methods. This study investigated the effect of 3 commercially available Imidacloprid gel baits on the palatability of dead cockroaches and, consequently, on the efficacy of secondary killing. German cockroaches killed by the gel baits and others killed by freezing were offered to conspecifics, the numbers of cannibalistic cockroaches and dead cockroaches, as well as weight loss were recorded. Despite the content of Imidacloprid is identical in all the baits, the palatability of the cockroach killed by the gel consumption and used as food was different between the 3 commercial products, with consequences on the secondary killing effect. These results suggest as the bait co-formulants play an important role not only on the palatability of the bait but also in the palatability of the dead cockroaches which are eaten by conspecifics, and therefore, in the result of a pest control application.