Cockroach connoisseurs: effects of contamination on gel bait efficacy and consumption by German cockroaches (Blattodea: Ectobiidae) under laboratory conditions

Baits are one of the most effective German cockroach (Blattella germanica L.) control methods. However, despite their efficacy, the nature of their application causes them to be prone to contamination with a number of potential chemicals. This contamination, either by other insecticides or commonly used cleaning products, is therefore touted as a reason for bait failure. To address this concern, this study evaluated the efficacy and consumption of 2 cockroach gel baits (Advion, Maxforce FC Magnum) after contamination with a variety of insecticides and cleaning products. Contamination of baits did not affect efficacy, with only those baits treated with DEET, the botanical insecticide Ecoraider (Maxforce FC Magnum only), and the pyrethrin flushing agent PT 565 Plus XLO (Maxforce FC Magnum only) showing a significant increase in survivorship and with most contaminated baits exceeding 90% mortality within 7 days. Consumption of contaminated baits was more varied, but similar to mortality, significantly reduced consumption was only observed for baits treated with DEET, Ecoraider (Maxforce FC Magnum only), and PT 565 Plus XLO (Maxforce FC Magnum only). These findings show that German cockroaches will readily accept contaminated baits under laboratory conditions and suggest that contamination of cockroach gel baits is not likely the primary cause of product failure.