HOUSEHOLD AND STRUCTURAL INSECTS Cost and Efficacy Comparison of Integrated Pest Management Strategies with Monthly Spray Insecticide Applications for German Cockroach (Dictyoptera: Blattellidae) Control in Public Housing

The long-term costs and efÞcacy of two treatment methodologies for German cockroach, Blattella germanica (L.), control were compared in the public housing environment. The “traditional” treatment forGermancockroaches consistedofmonthlybaseboard andcrack andcrevice treatment (TBCC) by using spray and dust formulation insecticides. The integrated pestmanagement treatment (IPM) involved initial vacuuming of apartments followed by monthly or quarterly applications of baits and insect growth regulator (IGR) devices. Cockroach populations in the IPM treatment were also monitored with sticky traps. Technician time and the amount of product applied were used to measure cost in both treatments. Twenty-four hour sticky trap catch was used as an indicator of treatment efÞcacy. The cost of the IPM treatment was found to be signiÞcantly greater than the traditional treatment, particularly at the initiation of the test. In the Þrst month (clean-out), the average cost per apartment unit was $14.60, whereas the average cost of a TBCC unit was $2.75. In the secondmonthof treatment, the average cost of IPMwas still signiÞcantly greater than theTBCC cost. However, after month 4 the cost of the two treatments was no longer signiÞcantly different because many of the IPM apartments were moved to a quarterly treatment schedule. To evaluate the long-termcostsof the two treatmentsover theentireyear, technician timeandproductquantitieswere averaged over all units treated within the 12-mo test period (total 600 U per treatment). The average per unit cost of the IPM treatment was ($4.06). The average IPM cost was signiÞcantly greater than that of the TBCC treatment at $1.50 per unit. Although the TBCCwas signiÞcantly less expensive than the IPM treatment, it was also less effective. Trap catch data indicated that the TBCC treatment had little, if any, effect on the cockroach populations over the course of the year. Cockroach populations in the TBCC treatment remained steady for the Þrst 5mo of the test and then had a threefold increase during the summer. Cockroach populations in the IPM treatment were signiÞcantly reduced from an average of 24.7 cockroaches per unit before treatment to an average 3.9 cockroaches per unit inmonth 4. The suppressed cockroach populations ( 5 per unit) in the IPM treatment remained constant for the remaining 8 mo of the test.