Brenner, BL, S Markowitz, M Rivera, H Romero, M Weeks, E Sanchez, E Deych, A Garg, James Godbold, MS Wolff, PJ Landrigan and G Berkowitz. 2003. Integrated pest management in an urban community—a successful partnership for prevention. Environmental Health Perspectives, on line 3 July 2003.

Integrated pest management reduces cockroach infestations effectively, and it does it at equivalent or less economic cost than chemical spraying. That's the conclusion of a research project carried out by Mt Sinai Medical Center and two community health centers in East Harlem, New York. After a 6-month intervention by IPM experts, treated homes had reduced cockroach numbers by over half, whereas homes in a comparison group without IPM treatment saw no decrease in infestations.

What did they do? Brenner et al. carried out an experiment comparing the effectiveness of two different approaches to reducing cockroach infestations, IPM vs. a control group that received no special instructions.

Mothers recruited to the experiment had recently received prenatal health care at one of the participating health centers; upon recruitment they were interviewed using a questionnare about a variety of socioeconomic factors and chemical spraying history in the home.

During the experiment, residents in the control group made their own choices about methods of combat cockroaches, including spraying. Participants in the control group were given a basic "home injury prevention intervention program" that consisted of one-on-one instructions for preventing injuries, avoiding emergencies, selecting a baby-sitter, etc.

In the IPM group, IPM specialists trained residents to use standard tools of integrated pest management: "education and instruction in non-toxic IPM methods by the project health educator; instruction in better housekeeping and sanitation and garbage removal practices; repair services to seal cracks and crevices by a project handyman; fixing plumbing leaks; least toxic supplies including zone monitors, plastic bait stations and gel rather than pesticide sprays; expert advice from pest control experts; and advocacy with building management to introduce safe pest control practices."

Prior to the onset of the interventions, the research team assessed the level of cockroach infestations in each participating home. Levels were then monitored for the duration of the procedure.

What did they find? At the beginning of the study, three quarters of the families in both the IPM and control homes reported cockroach infestations. Approximately 60% of homes in both groups reported pesticide use during the pregnancy that had brought the mothers to the prenatal care units.

The cockroach monitoring stations revealed cockroaches in 80% of the homes of both groups at the onset of the study, with no difference apparent between treatment and control.

Six months later, the homes using IPM had reduced cockroach levels by over half, from 81% to 39% of households. A statistical analysis by the research team indicates this change was highly unlikely to be due to chance (p < 0.0001).

The research team tracked the percentage of cockroach monitoring stations that caught cockroaches over the duration of the experiment. The graph on the right shows a clear decrease over time. By the end of the experiment, over half the homes using IPM the number trapped fell to zero. Blue dots show the median; black bars the inter-quartile range. Adapted from Brenner et al.

In contrast, no significant change was observe in the control group. After 6 months, cockroach infestations had varied from 78% of units monitored to 81%.

The research team estimated the costs of the IPM treatments to be $46 to $69 per unit during the first year,and $24 per year after repairs were made. According to a commercial company involved in cockroach control, conventional treatment by spraying of chemicals would have cost approximately $24-$46, but would not have involved repairs.

What does it mean? Brenner et al. have clearly demonstrated that IPM offers an affordable, effective approach to cockroach control in urban dwellings, one that can be carried out with bringing hazardous insecticides into the home.

Many of the units monitored were in multiple unit dwellings. Skeptics of IPM had argued that this approach would only be viable, if at all, if entire multi-unit buildings cooperated simultaneously. These results show that people living within multi-unit buildings can benefit from IPM practices even if the entire building has not implemented IPM.

The authors note two key ingredients to the success of their program: hands-on training and assigning a building handy man to the variety of small repairs essential to effective IPM.