In this study, the researchers were interested in identifying effective, relatively inexpensive, readily available attractants for German cockroaches. As you know, sticky traps are the workhorse of IPM and are widely used across the industry to monitor many different urban pests in a wide range of accounts. Unfortunately, sticky traps without an attractant/lure/bait only catch cockroaches when the pests happen to wander onto the trap and become stuck. Of course, trap placement can maximize the probability of cockroach encounters, but catch rates are still dependent on chance. There are commercial lures available, but the authors were looking for cost-conscious alternatives that really worked.
One of the classic cockroach attractants that you will find in the old school textbooks is the use of stale beer and bread, placed inside a mason jar as a cockroach trap. With the prospects of learning about the hijinks that ensued at the Rutgers Urban Entomology lab while testing beers on cockroaches, I eagerly dug into this paper. But to my dismay, the researchers did not test beer styles as attractants. They did test 18 different attractants – including things like fish, blueberry, sugar cookie and root beer oils, synthetic German cockroach pheromones, peanut butter, and cumin seed oil. (Learn more about some undergraduate research at Texas A&M on cockroach beer preferences here.)
Curiosity got the best of me and I followed a rabbit trail to learn the source of their oil supplier. It turns out that you can find fragrance oils for more than 140 different smells on the manufacturer’s website – things like: baby powder, birthday cake and churros. In fact, in the description for bacon extract oil it stated that it could be used as cologne. But I digress.
Essentially, what they did at Rutgers was place 500 cockroaches into an experimental arena, introduced 4 sticky traps into each, and after 2 days compared the number of cockroaches caught on the traps containing attractants with those that didn’t. The attractants were placed cotton wicks that were placed inside a centrifuge micro tube (1.5 mL). They also performed head-to-head tests between attractants.
Here’s what they learned: Sticky traps containing apple oil, blueberry oil, orange oil (or their combinations), fish oil, peanut butter, commercial roach lure tablets or bacon extract had significantly higher catch rates than an un-baited traps.
Now, understand that these are laboratory results (with no competing food sources) so the researchers put the most promising attractants to the test in the field inside affordable housing apartments in Jersey City and Linden, NJ. They learned that on average, the combination of apple + blueberry oil, and the commercial roach lure tablet increased trap catch in infested apartments by 103% and bacon extract increased catch rates by 92%.
They did state that more research needs to be performed to determined accurate and reliable delivery methods for the attractants, but the bottom line is this: if you want to increase German cockroach catch rates in sticky traps – use commercially available roach lure tablets or combinations of apple + blueberry oil. Those perform best. But if you want to catch me in a sticky trap, try the bacon.
Jim Fredericks, PhD, BCE
Salehe Abbar, Changlu Wang, Laboratory and Field Evaluations of Food-Based Attractants for Monitoring German Cockroaches, Journal of Economic Entomology, Volume 114, Issue 4, August 2021, Pages 1758–1763, https://doi.org/10.1093/jee/toab080