Author ORCID Identifier

Date Available


Year of Publication


Degree Name

Master of Science (MS)

Document Type

Master's Thesis


Agriculture, Food and Environment



First Advisor

Dr. Zachary DeVries


Cockroach baits are one of the most effective tools used for German cockroach (Blattella germanica L.) control. This is due in part to the number of cockroach baits on the market with various matrix compositions and active ingredients, aiding in the control of resistant (physiologically and behaviorally) cockroach populations through bait rotation. However, it remains unclear how cockroach gel baits perform over time and under different environmental conditions. Therefore, we aged six cockroach gel baits for varying times (24 hours, one month, three months, six months) and at three relative humidities (15%, 40%, and 80%), and tested their performance (consumption and efficacy) against fresh baits. German cockroaches consumed various quantities of bait depending upon both bait product and age, with significant declines in aged bait consumption compared to fresh bait consumption for most products tested. However, all baits aged for over 24 hours caused greater than 93% mortality in all Blattella germanica (L.) populations. Low relative humidity (15%) did not significantly affect bait consumption or efficacy compared to standard relative humidity (40%), but high humidity (80%) resulted in excessive mold growth (Mucoraceae) in all trials, preventing testing of aged baits at high humidity. Our findings show that cockroach gel baits remain palatable and effective up to six months after application at 40% and 15% relative humidity. Secondly, we investigated the affect bait placement has on bait performance by applying cockroach gel baits (Maxforce FC Magnum gel bait and Advion Cockroach gel bait) onto glue traps and placed them at various distance (30 cm and 8 cm) from the harborage and arena walls in still air semi-field like arenas, to test their detectability on a field population of B. Germanica (L.). Laboratory results found that German cockroaches couldn’t detect bait when placed at 8 cm or farther from the harborage and arena walls. However, when investigating the impact of starvation with water deprivation and population crowding on bait detection, we discovered they resulted in significantly greater trap catch than the previous experiments. These results indicate that bait encounters are driven by foraging, not attraction.

Digital Object Identifier (DOI)

Funding Information

This study was supported by the Pest Management Foundation from 2020 to 2022, the U.S. Department of Housing and Urban Development Healthy Homes Program (KYHHU0061-20) from 2021 to 2023, and by the University of Kentucky College of Agriculture, Food and Environment Diversity Research and Teaching Fellowship from 2021 to 2023.