Aluminum phosphide (ALP) is used extensively for burrowing mammal control. However, recent changes have been made to the ALP label which could substantially limit its utility for burrowing mammal control in the future. As such, I developed surveys to help quantify the impact that these changes are likely to have on ALP usage and vertebrate Integrated Pest Management in California. These survey findings were compared to information gathered from the California Department of Pesticide Regulation’s Pesticide Use Report for 2010 to relate the survey findings to the broader spectrum of users throughout California. I found that 49,005 lbs of active ingredient (AI) of ALP was used for burrowing mammal control in 2010, with most applications occurring in residential areas, applied primarily by licensed Pest Control Operators who specialize in vertebrate IPM. Most applications were applied to control pocket gophers, while ground squirrel and mole burrow systems were also treated. Collectively, new buffer and posting restrictions resulted in expected losses of 70% and 26% of agricultural applications of ALP for pocket gophers and ground squirrels, respectively. The impact of restrictions in residential areas may be even more extreme, with estimated reductions in ALP applications ranging from 70-98%. Alternative control methods were typically considered less efficacious than ALP. Furthermore, 13-34% of respondents indicated that they would no longer control these pests in areas where they could not use ALP. Insufficient or ineffective management programs targeted at these pests could result in increased economic damage, greater human health and safety concerns, and increased environmental degradation. Even though ALP has a safe track record in California, ALP users were willing to obtain greater training on its safe use while adhering to a 67% increase in the previous 15-foot buffer restriction, if it meant relaxing some of the current restrictions. Because of the extreme importance of burrowing mammal control, combined with the high efficacy and safe track record of ALP, perhaps these or alternative mitigation steps should be considered to ensure the safe and effective use of ALP. Otherwise, it is quite possible that the estimated 85% reduction in future ALP applications for burrowing mammal control could result in far greater negative consequences than the benefits gained from the new regulations.
