CONSIDERATIONS FOR INTEGRATED PEST MANAGEMENT AT ZOOS

Key pest management issues at zoos are rat and mice control, insect (primarily cockroach) control, nontarget concerns, and identification of nonchemical alternatives. A zoo poses unique problems because it is necessary to control pests without harming exhibit specimens. Both the primary toxicity of the materials used as well as relay toxicity should be considered (e.g., zoo animals consuming insects and dead rodents contaminated with pesticide). Because of these risks, trapping is preferred over baiting for removal of vertebrate pests, unless there is severe rodent overpopulation (Spelman, 1999). Fogging and fumigation should be strictly controlled, and only certified, experienced applicators should be used. A pest management program should be the responsibility of senior management personnel (limited to a very few people) who are knowledgeable about pest management principles. Each aspect of the program should be reviewed prior to implementation, and chemical storage, inventories, safety procedures, application techniques, and legal aspects (e.g., adherence to Environmental Protection Agency pesticide and state or local rules and requirements for certified applicators, restricted use pesticides, use concentrations) should be fully discussed before the pest management department conducts an application.

Personnel directly responsible for the pest management program should be knowledgeable in all areas of pest management operations and should regularly attend continuing education in professional pest management. The input of management, curator staff, safety department, exhibit personnel, keepers, and the sanitation department is essential for a successful pest management program.

A successful IPM program at a zoo includes several steps to control, reduce, or eliminate pests (Spelman, 1999). These may include inspection, exclusion and habitat management, sanitation, trapping, baiting, repellents, and other methods. As a preventive measure routine inspection of animal facilities may identify a pest problem before developing into an infestation. Physical barriers (e.g., fencing, netting, and roofing) provide a first line of defense against pest infestation (Spelman, 1999). Habitat management is intended to reduce the attractiveness of an animal enclosure to the pest.

Sanitation and proper storage and removal of solid waste (bedding, feed, enrichment items, dirt, and debris) are important steps in pest management (AAZV, 1999). Appropriate food storage bins that are well sealed will reduce potential pest problems. Cleaning and disinfecting food and water containers should occur routinely (AAZV, 1999). Public areas (e.g., walkways, concession areas) should be cleaned regularly, and the public should be discouraged from feeding animals (Spelman, 1999). The Animal Welfare Act (7 U.S.C. s/s 2131 et seq.) contains specific sanitization regulations for certain animals in captivity (e.g., indoor primary enclosures for nonhuman primates must be sanitized at least once every two weeks).

Physical (trapping), chemical (baiting, repellents, and fumigation), and biological controls (predators, contraceptive vaccines, species-specific disease) may need to be used for more severe pest infestations. Trapping of pests reduces the risk of relay and nontarget toxicity that may occur in zoos, and it is preferred except in the cases of severe rodent infestation (Spelman, 1999). Biological controls may be used in very specific situations when carefully monitored (e.g., an oral contraceptive agent [viral vectored immunocontraception] may prove effective for the control of feral rabbits and red fox (Holland and Robinson, 1995) although there is currently no biological control for rodent infestations).

Chemical use should be considered a last resource for pest management because of the aforementioned toxicity concerns; indeed, intoxication from chemical use in zoos has been reported many times. Pesticide use at zoos is a concern because of potential impacts on animal health. At the National Zoo two red pandas died as a result of ingesting aluminum phosphide placed in the animal enclosure to control a rodent infestation (see Box 4-1) (Enquist and Montali, 2003). Second-generation anticoagulant rodenticides have been associated with toxicity and in some circumstances death in several bird species: white-winged wood duck (James et al., 1998); turkey vultures, kookaburra, von der Decken's hornbill, and crested wood partridge (Borst and Counotte, 2002). Additional specific chemical toxicities in wildlife have been reviewed thoroughly (Fowler, 1978; Plumlee, 1997).

BOX 4-1

Lack of Procedures Jeopardizes Animal Welfare: Red Panda (Accession #113194 and #111967) Deaths. Prior to the panda deaths the National Zoo was experiencing a growing rat problem. An outside contractor was hired, but proper procedures were not in place (more...)

PEST MANAGEMENT AT THE NATIONAL ZOO

On January 10, 2003, when two red pandas consumed restricted-use fumigant tablets and later died, pest management was the responsibility of the safety manager. Although a contractor applied the fumigant, the application was carried out under the direction of an onsite zoo employee (a certified pesticide applicator located in the Office of Safety) who manages some pest management programs. At the National Zoo at that time the certified pesticide applicator was responsible for in-house chemical applications and baits targeted for insects, as opposed to large treatments such as rat fumigation. To become a certified pesticide applicator, an individual must complete training and pass an examination administered by the state or local authority that enforces Environmental Protection Agency regulations for pesticides (Federal Insecticide, Fungicide, Rodenticide Act; 7 U.S.C. s/s 136 et seq. as amended). This certification allows the person to purchase and apply restricted-use pesticides and is typically a benchmark for training.

After the red panda deaths the National Zoo transferred responsibility for the Pest Management Program to the Pathology Department. An Integrated Pest Management (IPM) committee has been formed to address the animal and insect pest problem at the zoo. Since February 28, 2003, the IPM committee has conducted routine inspections of the zoo to identify areas that require pest management attention (NZP, Integrated Pest Management Team Review, September 22, 2003). Additionally, the National Zoo began the process of establishing a comprehensive program to address the widespread pest problem (NZP, General Memorandum Draft, September, 2003), including creation of a pesticide program manager position, which was subsequently filled by an entomologist with IPM experience.

Since the red panda deaths, a number of actions have been taken to address issues associated with both vertebrate and insect pests at the zoo (NZP, Integrated Pest Management Team Review, September22, 2003):

• Suspension of fumigation as a primary rat control technique.
• Recovery of numerous poison bait boxes formerly used throughout the Rock Creek Park facility.
• Assessment with recommendations for infrastructural pest exclusion procedures in many of the animal unit facilities.
• Incorporation of trash receptacles with water-shedding covers at secondary holding sites.
• Introduction of animal food containers designed to exclude insects.
• Rat activity assessment and trapping in major harborage sites.
• Major roach reduction in a high-profile exhibit and holding areas with minimal pesticide application.
• Implementation of improved animal food management and feeding times, and redesign of some outside exhibits to reduce vermin attraction.
• Trash management coordination of daily pickup and removal of trash by FONZ and National Zoo personnel during peak visitor activity.
• Mosquito, wasp, and yellow-jacket trapping and control, and elimination of mosquito breeding sites.
• Educational sessions and reports on IPM activities to National Zoo and Smithsonian personnel.

Despite these efforts, housekeeping and site conditions are still poor in numerous areas throughout the zoo, both in public and in nonpublic areas. Unsecured refuse (garbage in bags outside cans) and litter were observed throughout the zoo complex. There is a lack of housekeeping and janitorial staff in public areas. Rodents (rats/mice) were present in animal exhibition areas and were observed crossing public walkways in daylight, which is significant because these pests are generally nocturnal. A Recent USDA inspection (USDA, 2004b) noted numerous mice were observed inside primate exhibit areas.

STRENGTHS AND WEAKNESSES IN PEST MANAGEMENT AT THE NATIONAL ZOO

Prompt and appropriate actions were taken after the deaths of the red pandas to address contributing factors. These actions included reassignment of pest management responsibilities, cancellation of the existing pest management contract, suspension of rat fumigation programs, formation of an IPM committee and draft of an IPM plan, and creation of a professional pest control manager position (NZP, Integrated Pest Management Team Review, September 22, 2003; NZP, General Memorandum Draft, September, 2003). However, emphasis on pest management should continue to address the existing pest problem fully. Site observations indicate that considerable work is necessary to ensure animal health and the aesthetic quality of the zoo (USDA, 2003). A comprehensive IPM plan for pest management needs to be finalized and should

• establish clear goals and objectives, (e.g., bring current populations of pests down to acceptable levels and maintain those levels using modern IPM techniques incorporating routine management of sanitation, janitoring, trapping, treatment, and inspection.
• incorporate the input of management, curatorial staff, exhibit personnel, sanitation, facilities, and safety personnel.
• be under the leadership and direction of a pest management expert and the auspices of the pest management department (other departments should not be allowed to alter or supplement the program).
• consider consolidating the nutrition department so that food stock is in a central location.
• include continued training, certification maintenance, and professional development for pest control managers.
• involve continuous reassessment and improvement.

Success in pest management has been achieved at other zoos with a comprehensive IPM plan (Collins and Powell, 1996). With the widespread rodent problem the National Zoo may initially need to use chemical controls to reduce rodent populations to levels that can be managed by nonchemical methods. Care should be exercised to select the most suitable products or chemicals to minimize the hazards to nontarget animals. Ensuring that accidental poisoning does not occur in the animal collection is a significant challenge. The Philadelphia Zoo has successfully used hydrogen phosphide pellets and anticoagulants (bromadiolone) to control rat populations, but anticoagulants (particularly brodifacoum) should not be used near bird collections because of its high toxicity (AAZV, 1999). Other zoos have used expertise from the USDA-APHIS Wildlife Service Program for pest management.