The bait surcharge program: research improves zinc phosphide use for vole control in alfalfa

This paper describes several unexpected benefits of rodenticide-registration research funded by the California Bait Surcharge Program. An enclosure-type study was conducted to determine efficacy of single, pre- and test-bait broadcasts (10 lb./ac.) of 0% and 2% zinc phosphide (Zn3P2, CAS #1314-84-7) steam-rolled-oat (SRO) groats to control voles (Microtus spp.) in alfalfa (Medicago sativa). Unexpected research spinoffs resulted from the use of: 1) eight randomly-located, sieved-dirt plots per enclosure to monitor bait distribution, bait removal, and rodent/avian (non-target) activity; 2) a bait-weathering plot and bait-sample analyses to monitor Zn3P2 biodeterioration; and 3) a C++- language program to derive theoretical benefit-cost ratios associated with Zn3P2-bait broadcast