Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/10/1997
Publication Date: N/A
Citation: Interpretive Summary: Cockroaches can cause serious allergies to humans, and have the potential to spread germs and filth to the surfaces they contact. Scientists from the Agricultural Research Service's Center for Medical, Agricultural, and Veterinary Entomology, and Colgate-Palmolive's Corporate Technology Center (Household Surface Care R& D) have developed spatial analysis techniques as an important step to developing reduced-risk products for managing cockroach infestations. In studies conducted at ARS facilities in Gainesville, FL, they demonstrated that an Ajax cleaner with repellent prevented 92-96% of German cockroach populations from reinfesting previously infested areas for the duration of the 4-week studies. Spatial analysis techniques also were used to measure the area of infestation, and the area subsequently afforded protection by the repellent. These techniques will be useful to scientists in measuring risks associated with pests, and in determining practical expectations for using repellents to prevent infestations in homes and to safeguard critical areas from cockroach contamination. Expected benefits from continued cooperative research include cleaners and other products that reduce likelihood of cockroach infestation without the use of traditional insecticides.
Technical Abstract: Spatial statistical analysis (kriging) was used to compare and quantify the distribution of German cockroaches among harborages before and after application of a repellent solution to areas encompassing at least 85% of the cumulative distribution. Trials consisted of 16 yellow-laminated Plexiglas harborages in 1.2 x1.2 m arenas, and concurrent studies involving 49 harborages in a 6 x 8 m room. Results in arena and room trials were similar. In rooms under 12L:12D or continuous lighting conditions, harborages cumulatively encompassing 89-95% of the population (18 or 19 of 49 harborages) were treated with 0.63 g of an aqueous Ajax liquid cleaner formulation containing 2% n-methyl neodecanamide (MNDA) repellent. All other harborages received an equal volume of water. Subsequent spatial analysis revealed a dramatic shift of 96-98% of the reintroduced cockroach populations to non-repellent treated harborages; patterns persisted for the duration of the study (28 d (12:12) and 20 days (continuous)). Spatial analysis was also used to quantify the areas of emigration and immigration resulting from the repellent; 89% of the population was redistributed into 16.7 m2, leaving 11% of the population in the remaining 28.5 m2, with only 2-4% of the population remaining in the 16.1 m2 that originally contained 89% of the cockroach population.