Because zinc phosphide is poisonous to all animals, store it away from humans and pets. Wear rubber gloves to avoid contact with the chemical. Take extra care to avoid breathing zinc phosphide dust. When poison grain baits are applied according to directions, they usually result in an 80 to 90 percent reduction in prairie dog numbers. Unsuccessful control generally is due to the presence of green grass or failure to prebait.
Fumigants Use fumigants when additional control is required.
Aluminum phosphide and gas cartridges are legal for use in Colorado. Trade names for aluminum phosphide include Phostoxin, Gastoxin and Fumitoxin. Aluminum phosphide is classified as a restricted use pesticide and gas cartridges are classified for general use. Fumigants are most effective when used in moist soils in early spring. Product labels vary among manufacturers and with time.