German Cockroach Pest Management

For example, the traditional approach to controlling German cockroaches includes the application of residual insecticides to infested harborages, usually on a scheduled (monthly) basis. A pest management approach integrates chemical and non-chemical control strategies, and uses monitoring techniques to determine the need for pesticide application - irrespective of a schedule. Pest management methods and materials are not new to professional pest control, but they are rarely brought together in a single program - a pest management program.

There are examples of pest management strategies and successful German cockroach management programs that can provide guidelines for professional pest control operators. Gupta et al. (1973) used organic and inorganic insecticides, and sanitation in a program for urban apartments. Slater et al. (1979) and Robinson and Zungoli (1985) designed and implemented programs for urban apartment buildings. Bertolf et al. (1987) evaluated sanitation in a pest management program. Donahue et al. (1989) reported on insect growth regulators in a cockroach management program. Hedges (1990)reported on cockroach management in restaurants.

The German cockroach management program designed by the Urban Pest Control Research Center for use in Virginia Department of Corrections (DOC) facilities was based primarily on monitoring pest infestations with sticky traps, and using toxic bait stations (Maxforce) to reduce infestations. Residual insecticides were used only when cockroach infestations were large, and only in locations where cockroaches were trapped. The aspects of the program that related to kitchens and food preparation areas will be presented here.

DEPARTMENT OF CORRECTIONS. A German cockroach management program was designed for kitchens in three DOC operations: James River, 300 inmates (kitchen 1); Nottoway, 600 inmates (kitchen 2); and Powhatan, 600 inmates, two kitchens (kitchens 3 and 4). The kitchens contained the usual food preparation machines, ovens, sinks and food-storage areas. The staff was composed primarily of inmates. Meals were served three times a day, every day.

The previous pest control program was provided by the DOC and consisted of monthly residual insecticide applications with a compressed-air sprayer using fan and pin steam nozzles. Applications were directed to baseboards, under tables and to walls behind machines and stoves. Spray applications were usually done during the day and were often followed by ULV treatment (3% pyrethrins) in the evening. The insecticides used in the kitchens during the previous three years included diazinon, chlorpyrifos and propoxur. Pyrethrins were used in ULV applications, and as a flushing agent.

PEST MANAGEMENT PROGRAM. The components of the pest management program were: 1) techniques to monitor the pest population; 2) basic information on the infestation level and distribution of the target pest; 3) information on the target audience; 4) chemical and non-chemical control strategies; 5) training; and 6) evaluation.

Target pest. Although there were American cockroach infestations in some areas, German cockroaches were the most common pest. Infestations were often serious in the inmate dormitory and cell block areas, and the kitchen areas also experienced large infestations. The cockroach infestation level in the kitchens was measured with sticky traps, placed for 24 hours. Before the start of the management program an average of 10 cockroaches per trap were collected from rooms or specific zones in the kitchens; the average number of roaches per trap ranged from six to 18.

Target audience. The kitchen staff was provided printed information on the pest management program before it was implemented. Emphasis was placed on monitoring with sticky traps and the use of toxic bait stations. Kitchen staff and cleaning personnel were instructed not to remove or relocate sticky traps.

Monitoring and action levels. German cockroach infestations in the kitchens were monitored with three to five sticky traps per room (or distinct zones in large rooms) for 24 hours each month. The number of cockroaches trapped in each room or zone were averaged, and that number became an "action threshold" and used to make control decisions. Action thresholds used in the program are shown in Table 1.

A calendar listing the monthly maintenance and sanitation inspection duties assisted the technicians in record keeping and monitoring pest infestations. The number of cockroaches found in the sticky traps, as well as the control strategies implemented, were recorded on the calendar.

CHEMICAL, NON-CHEMICAL STRATEGIS. The non-chemical aspects of the pest management program involved increased emphasis on sanitation. The pest control technicians evaluated and reported (with a standardized form) sanitation problems to kitchen supervisors and administrative personnel. Sanitation problems were reported only for areas that had received control measures and continued to have an unacceptable cockroach infestation. The chemical strategies included the use of a microencapsulated organophosphate insecticide (PT265A-Knoxout), boric acid powder applied to wall voids, and Maxforce bait stations placed throughout the kitchens and adjacent storage rooms. All liquids and dusts were applied to cracks and crevices, and were used only as a supplement to the control provided by the bait stations.

An average of 35 Maxforce bait stations were used in each of the kitchens. The actual number of stations used depended on kitchen size. Stations were used at the rate of approximately one station per 500 square feet. Bait stations were placed In corners near all potential cockroach harborages. Placement of the stations was carefully monitored, and the locations recorded. Stations were replaced on a four-month basis.

Training. The Department of corrections pest control personnel were provided classroom-style training and resource/training manuals. The training program included a total of nine days of lectures, on-the-job training and a written test. The training manuals (75 pages) presented basic concepts of pest management and procedures for monitoring and control. Additional resources available to technicians included the book Scientific Guide to Pest Control Operations (Bennett, Corrigan and Owens 1988, Harvest Publishing Co.), and a subscription to the bi-monthly newsletter, "Techletter." Manuals (20 pages) were also provided to the food-handling staff and administrators to acquaint them with the overall management program, and the sanitation reports and treatment records technicians would prepare and maintain.

Evaluation. Evaluation of this program involved recording 1) the reduction of cockroach infestations, 2) reduction of pesticides used and 3) the cost effectiveness of the program. Through the use of consistent monitoring techniques and number of cockroaches collected in the sticky traps each month provided a measure of the program’s effectiveness. The monthly records of the sticky trap catches, and documentation of the amount of insecticide applied to each kitchen made evaluation of the program simple. The cost effectiveness of the management program, based on the amount of technician time, and comparing the amount of insecticides used with and without the management program, also provided valuable information.

PROGRAM RESULTS. The dramatic measure of the success of the program was the percentage reduction of the German cockroach infestations in the kitchens. The average reduction for the first month of the management program was 65 percent. However, by the fourth month 94 percent reduction was achieved, and in the sixth and seventh months cockroach reduction continued to improve. The number of cockroaches trapped in the kitchens after approximately one year of the pest management program (June 1990) was dramatically lower than the number trapped before the program stared (June 1989).

Materials and work hours. The cost of technician work hours, and insecticides (liquid sprays and bait stations) and sticky traps used with and without the pest management program was compared. Records for three years preceding the management program indicated that the average yearly cost per kitchen of pest control materials was $76, and the cost of technician work hours was $105. Pest management program materials averaged $157, and the work hours averaged $116 per kitchen. The actual number of hours required to treat kitchens with both programs was nearly equal. For example, the average time to treat the James River kitchen was 1 hour and 20 minutes, and the average time to treat the same kitchen with the pest management program was 1 hour and 35 minutes. The use of sticky traps and time spent in placing and picking up and counting the roaches on the sticky traps contributed to the increase in time spent by the technician. Sticky traps were the most significant addition to the costs of the pest management program. In the pest management program there was a 99 percent reduction in insecticide sprays and dusts applied to each kitchen, and a 97 percent reduction in overall pesticide use. The decreasing cockroach population and the use of less expensive sticky traps would probably reduce the cost of the pest management program.

Monitoring pest infestation levels is an important part of cockroach pest management. The decision to apply (or not apply) additional insecticides in the environment would be based on the presence of the target pest. The costs associated with monitoring are unavoidable, sticky traps or some method of measuring the presence of the target pest is essential. The benefits of monitoring include the selective use of insecticides, and an indication of the program’s effectiveness. The reduced costs associated with the use of less insecticides to control infestations are measurable in dollars.

CONCLUSIONS. The German cockroach management program designed and used in several Virginia Department of Corrections facilities was successful. After seven months the management program significantly reduced the number of German cockroaches in the kitchens, and also reduced the amount and frequency of insecticide applications below what existed before the program. This pest management program was based primarily on monitoring cockroaches with sticky traps, and the use of toxic bait stations to control infestations. Liquid sprays and dusts were used to supplement the bait stations. Residual insecticides were used only when infestations were large, and only in specific areas. Other aspects of the program included technician training sessions and resource manuals, in addition to an evaluation procedure.

William H. Robinson is with the Urban Pest Control Research Center at Virginia Tech, Blacksburg, Va. Eric Snell, a former graduate student at Virginia Tech, is currently with Western Pest control, Leesburg, Va. To learn more about their research, contact: Urban Pest Control Research Center, Virginia Tech, Blacksburg, Va. 24061.

REFERENCES

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Donahue, W.A., D.N. VanGundy, W.C. Satterfield, L.G. Coghlan. 1989. Solving a tough problem. Pest

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Gupta, A.P., Y.T. Das, J.R. Trout, W.R. Giscora, D.S. Adam, and G.J. Brordash. 1973. Effectiveness of

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Hedges, S.A. 1990. Roach control in restaurants. Pest Control Technology 18(7):50-55.

Robinson,W. and P. Zungoli. 1985. Integrated control program for German cockroaches in multiple-unit

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Slater, A.J., L. McIntosh, R.B. Coleman and M.J. Hurburt, 1979. German cockroach management in

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