Cost and effectiveness of community-wide integrated pest management for German cockroach, cockroach allergen, and insecticide use reduction in low-income housing.

Many low-income housing units in the United States continue to have chronic German cockroach, Blattella germanica (L.), infestations and high prevalence of cockroach allergens despite the availability of highly effective cockroach control products. Several studies have demonstrated the greater effectiveness of integrated pest management (IPM) compared with routine chemical interventions in apartment buildings and the benefit of cockroach allergen reduction using IPM. Yet, there has been little information on the cost and benefit of community-wide cockroach IPM, which is critical for voluntary adoption of IPM programs. We evaluated a community-wide IPM program in two low-income apartment complexes in Gary, IN. The program included education of staff and residents, monthly monitoring, and nonchemical (laying sticky traps) and chemical treatment based on monitoring results. One complex of 191 apartments was treated with cockroach gel bait, boric acid dust, and sticky traps by state licensed entomologists from Purdue University (E-IPM group). The other complex of 251 apartments was treated by pest management professionals (PMPs) from a contractor (C-IPM group) following the same protocol as the E-IPM group. Purdue University researchers trained Gary Housing Authority (GHA) staff on cockroach biology and management and cockroach allergen reduction techniques. GHA staff educated all residents in the two complexes on cockroach control and allergen reduction through printed materials, demonstrations, or both. Purdue University entomologists conducted the initial and monthly monitoring in both complexes (laying six sticky traps per apartment and retrieving them the next day) with the assistance from GHA to evaluate program effectiveness, guide insecticide applications, and identify apartments with poor sanitation conditions. Dust samples were collected from kitchen floors of 72 cockroach-infested apartments at the beginning, and again at 6 and 12 mo to evaluate changes in cockroach allergen Bla g 1 concentration. E-IPM resulted in significantly faster cockroach trap count reduction than C-IPM. At 12 mo, the number of cockroach-infested apartments decreased by 74% in both treatment groups. Geometric mean cockroach trap counts decreased from 99.7 at baseline to 0.4 (99.6% reduction) by E-IPM and from 76.0 at baseline to 1.3 (98.3% reduction) by C-IPM. From the first quarter to the fourth quarter, cockroach bait use decreased by 88.5 and 92.7% for E-IPM and C-IPM group, respectively. From month 0 to month 12, geometric mean Bla g 1 concentrations decreased from 27.8 to 2.2 U per gram of dust (U/g) in the E-IPM group and from 5.8 to 2.4 U/g in the C-IPM group. Assuming salary rates at $60/h for PMPs and $19/h for housing authority staff, the mean monthly cockroach management (material and labor expenses) cost was $7.5 USD/apartment for both groups excluding education cost. The cost for subsequent years service is expected to be lower due to reduced cockroach infestations. The effectiveness of both IPM programs was affected by the lack of assistance from housing authority with periodic inspections of the apartments, lack of proper maintenance of the properties, and inadequate cooperation from residents.