Cost-effectiveness of five burrow fumigants for managing black-tailed prairie dogs

We evaluated the cost-effectiveness of two solid form burrow fumigants (aluminum phosphide and gas cartridges) and three pressurized gas–liquid burrow fumigants (methyl bromide, chloropicrin, and a methyl bromide–chloropicrin mixture) for managing black-tailed prairie dogs (Cynomys ludovicianus). Fifty-two variable-sized plots, including 25 treatment and 25 control burrows, were established within 13 prairie dog colonies in central Nebraska during spring 1989. Each group of 25 treatment burrows was fumigated with one of the five fumigants according to label directions or manufacturer recommendations. All five fumigants reduced burrow activity 95–98%, as measured by a plugged burrow technique. No significant differences in efficacy (P=0.453) were detected among the five treatments. Total costs for materials and labor for the aluminum phosphide and gas cartridges, excluding application equipment, were twice ($75.00 to $96.88 ha−1) the cost of the pressurized gas–liquid fumigants ($37.67 to $41.76 ha−1). Costs for the application equipment were considerably higher for the pressurized materials. Each treatment required labor for burrow plugging, which accounted for 50–75% of the total cost. None of the products tested met all requirements of a proposed selection criteria for fumigants.