Horizontal Transfer Of A Novel Isocycloseram Bait On German Cockroaches (Blattodea: Ectobiidae)

We examined the horizontal transfer potential of a 0.1% isocycloseram gel bait formulation on a susceptible strain of German cockroaches (UCR) in comparison with commercial baits available in the United States containing 0.6% indoxacarb, 0.05% fipronil, 0.5% dinotefuran, or 0.5% clothianidin + 0.5% pyriproxyfen. To examine coprophagy and emetophagy, adult male cockroaches were provided access to bait in a choice test with dog food as the alternative food source, which killed 85–100% of cockroaches within 24 h. The bait and carcasses were removed, and new groups of adult males were transferred to the arenas containing excretions from previous males. The secondary exposure killed 93–100% of cockroaches within 7 d (mean survival time 1.6 d for 1% isocycloseram; other baits 1.0–3.5 d). To examine the effect of necrophagy, adult males were exposed to bait for 24 h, which killed 92.5–97.5% of cockroaches across all baits. The dead adult males were transferred to clean arenas with 30 first and second instars with access to dog food. Nymphs exposed to isocycloseram-killed males experienced 99.2% mortality within 14 d, while mortality with other baits was 15.3–96.7%.