Performance Of Commercial Cockroach Gel Baits Against Field Populations Of The German Cockroach, Blattella Germanica, From Singapore

Insecticide resistance in the German cockroach, Blattella germanica (L.), is a significant challenge affecting pest management professionals worldwide. The use of gel baits against German cockroaches has become a popular option in Asia. However, recently, there were anecdotal reports that the field performance of some cockroach gel baits has declined. In this study, we evaluated the performance of four commercial gel baits containing 0.01% fipronil (Maxforce® FC Professional Insect Control Roach Killer Bait Gel), 2.15% hydramethylnon (Maxforce® Professional Insect Control Roach Killer Bait Gel), 2.15% imidacloprid (Premise® Cockroach Bait), and 0.60% indoxacarb (Advion® Cockroach Gel Bait) against 22 field-collected populations of B. germanica from Singapore, in the presence of food and water for up to 14 d. Results showed that with
exception to the indoxacarb baits (100% mortality against all stages of all strains), all tested baits exhibited varying effectiveness against the insecticide-resistant strains. The efficacy of all baits against adult males was encouraging (fipronil: 77.5 – 100%, hydramethylnon: 92.5 – 100%, imidacloprid: 82.5 – 100%, and indoxacarb: 100%). When tested against the adult females and mid-instars of the field strains, fipronil caused 77.5–100% and 35.0–95.0% mortality, respectively. The hydramethylnon bait’s effectiveness was moderate to high against adult females (42.5–100%) and mid-instars (40.0–97.5%), whereas the imidacloprid bait showed poor to high performance against mid-instars (10.0–82.5%) and moderate to high performance against adult females (52.5–95.0%).