The tropical zones of Latin America are sources of a great faunal richness. A significant number of mammals are associated with damage to the agricultural and livestock industries of Colombia. Some studies have indicated that rodents cause serious economic and social damage in the agricultural, livestock, and stored product sectors of the Colombian economy. Evaluations of this damage have been based on three criteria: 1) the characteristics of the damage; 2) the species of rodent involved; and 3) the loss of production at harvest. Cereals and oil-producing crops are most affected as standing crops; in the livestock area, poultry and pork production are most affected; many agricultural products, especially grains, are attacked by rodents during the post-harvest stage. The level of economic loss caused by rodents can range from about 4% to about 50% depending on the crop, the season, and the species of rodent involved in the damage. Social damages are characterized by the transmission of illnesses such as salmonellosis and leptospirosis via contaminated foods or grains. Six species of rodents of the families Cricetidae and Muridae are most commonly associated with these problems in Colombia.

The 1988 Amendments to the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) accelerated the reregistration schedule for pesticide products registered with the Environmental Protection Agency (EPA) prior to 1984. The compound 3-chloro-p-toluidine hydrochloride (DRC-1339), an avicide registered to control 14 pest bird species, was included on Pesticide List B published by EPA. For the reregistration of DRC-1339, 44 studies were required− 22 product chemistry, 7 wildlife/aquatic hazards, 8 human/domestic animal hazards, 5 environmental fate, and 2 residue chemistry studies. In 5 acute human-health-hazards studies, DRC-1339 was found to: (1) have an oral LD50 of 330 (272-401) mg/kg in rats, (2) have a dermal LD50 of >2.0 g/kg in rabbits, (3) cause corrosive effects to the eyes of rabbits, (4) cause corrosive effects to the skin of rabbits, and (5) induce dermal sensitization in guinea pigs. Results support the current precautionary statements on the "use labels" warning of harmful ingestion, inhalation, dermal absorption and eye irritation effects to users of the active ingredient.

Public and governmental concerns about the health, safety, and environmental impacts of pesticides have led to increased regulatory requirements to determine the hazards and risks associated with their manufacture, distribution, and use. Vertebrate pesticides are regulated by the U.S. Environmental Protection Agency (EPA) under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as amended. Much of the data required for registration of these pesticides will be generated by commercial testing laboratories under contract to the product registrants or sponsors. In this paper, we address aspects of the contract research process including: 1) an overview of FIFRA requirements, 2) the nature of the contract research process, 3) guidelines for setting up and administering a contract for this type of work, and 4) several case studies to illustrate some of the "pitfalls" that may be encountered. The information presented is based on the collective experience of the authors' involvement with 49 contracted studies over a three-year period.

In laboratory tests with adult coyotes (Canis latrans) a pyrotechnic fumigant containing two active ingredients, sodium nitrate and charcoal, was found to be just as effective as the U.S. Fish and Wildlife Service Gas Cartridge that contains six active and two inactive ingredients. The two-ingredient cartridge produces high concentrations of carbon monoxide. Field tests with cartridges containing 240 g of 65% sodium nitrate and 35% charcoal produced a 96% mortality rate in coyote pups. A cartridge containing 65 g of 65% sodium nitrate and 35% charcoal was effective in both laboratory and field tests on wild Norway rats (Rattus norvegicus). In field tests conducted at a rat-infested cattle feedlot, there was a 77% average (35% to 95% range) reduction in numbers of reopened burrows after fumigation as compared to pretreatment figures. Sodium nitrate and charcoal are not dangerous chemicals. The acute oral LD50 for both sodium nitrate and charcoal is greater than 3,000 mg/kg in rats, and there was no potentiation when given in combination at 3,000 mg/kg. No signs of secondary toxicity were observed in bobcats (Lynx rufus) fed rats killed by fumes from burning sodium nitrate and charcoal. Since gas cartridges are used underground, potential hazards to humans and the environment are nil. When the cartridges are used properly, they are effective devices for controlling vertebrate pests such as coyotes and rats.