Toxicity and repellency of novel formulations of 2-undecanone, organic fatty acids, and sodium lauryl sulfate against German cockroaches

Several novel chemical formulations were tested for their insecticidal and repellent activities against the German cockroach, Blattella germanica (L). Single compounds or formulations tested were 2-Undecanone, BioUD®8 (silicone oil with Soy methyl ester (SME) and 8% 2-Undecanone in a H₂O emulsion), BioUD10 (anhydrous; vegetable fatty acids with SME and 10% 2-Undecanone), BioBlock® concentrate (vegetable fatty acids and Sodium lauryl sulfate in a H₂O emulsion), BioBlock with added enzymes (BBE), DEET (N,N-Diethyl-meta-toluamide), and Raid® Max (0.101% Imiprothrin and 0.05% Deltamethrin a.i.). Direct application onto the dorsal surface showed a significantly higher mortality rate for cockroaches treated with 2-Undecanone than for those treated with Raid, while cockroaches treated with BioUD10 and BioBlock showed no significant differences, and cockroaches treated with BioUD8, BBE, or DEET showed significantly lower mortalities. All tested formulations acted slightly faster on males than on females, and older adults were less impacted than younger ones. For the indirect treatments, different doses of each formulation were applied to the bottom of polypropylene cups. Significant dose effects were found for 2-Undecanone and BioBlock, but not for BioUD8. 2-Undecanone killed cockroaches very fast in a short time period at higher doses, while BioBlock took longer to act. For the repellency experiments, half of the bottom of each cup was treated. BioUD8 and BioBlock were not significantly different from DEET, while pure 2-Undecanone lost its repellent activity fast at lower doses.