Wildlife Damage Management, Internet Center for


Date of this Version

February 1980


Published in Proceedings of the Fourth Eastern Pine and Meadow Vole Symposium, Hendersonville, NC, February 21-22, 1980, Ross E. Byers, editor. Copyright © 1980 Marshall.


Since the loss of DDT, Vacor (DPL 787) and other acute rodenticides and the serious use restrictions placed upon strychnine and 1080 for field use, it has become quite apparent that control of field rodents, more particular pine and meadow voles, with standard anticoagulants has become a difficult task, and in some instances impossible.

Bell Laboratories, Inc. has chosen to take a very serious look at many of the older compounds and rework and reformulate these compounds into palatable and efficacious finished baits. After 5 years of research and development. Bell Laboratories, Inc. has recently registered, with the Environmental Protection Agency, a new acute single dose bait formulation containing 2% zinc phosphide, namely ZP Rodent Bait AG.

ZP Rodent Bait AG is registered for control of ground squirrels in non-crop areas, prairie dogs in rangeland, rats in sugar cane and meadow and pine voles in apple orchards and non-crop areas.

Prior to the EPA registration of Bell Laboratories' ZP products (tracking powder, commensal rodent bait and ag bait) it was generally believed and accepted that the active Ingredient, zinc phosphide, reacted with the moisture in the atmosphere to release phosphine gas. Based upon field and laboratory studies, it has been determined that zinc phosphide is an extremely stable compound and degradation occurs only when the compound comes in direct contact with dilute acids or by the mechanical factors of weathering (wind and rain) where the compound is physically removed from the base material.