Comparative Repellency of Common Essentials Oils and Commercially Available Repellents Against the German Cockroach (Blattella germanica)


  • Francesca Scalise Texas A&M Student
  • Molly Totten
  • Christian Vormohr
  • Elise Woodruff
  • Lacey Restemyer


Blattella germanica (Blattodea: Ectobiidae), the German cockroach, has been known to be attracted to various bacteria-laden surfaces such as feces and garbage, as well as food. The tendency for these cockroaches to transfer bacteria onto the food humans eat present a method of entry for bacteria into the human system, and therefore contribute to overall mechanical disease transmission. B. germanica does not only contribute to disease transmission, but also to a large amount of asthmatic reactions in humans. These negative effects, combined with this species tendency to live inside human dwellings, heightens the need for an effective repellent against them. Since repellents require application within homes, it is essential that it is non-toxic and safe. A current option other than manufactured repellents may be the use of essential oils. In this study, a combination of various commercially-available insect repellents as well as essential oils were assessed in terms of repellency against B. germanica. This assessment was completed through the observation of the amount of time necessary for a B. germanica cockroach to cross over a substance-treated filter paper when attracted by white bread. It was found that, while certain commercially-available repellents proved more effective than some essential oils, essential oils still demonstrated significant repellency and were more repellent than DEET, a commercial repellent with known adverse effects. This provides implications for further development of safer and potentially less expensive repellents, particular in future usage in Integrated Vector Management programs.