Date of this Version
Broadcast treatments of Volak (Brodifacoum), Rozol (Chlorophacinone), ZP Rodent Bait AG, and Ramik-Brown (Diphacinone) gave excellent to good control of voles in decreasing order of effectiveness. A saccharin formulation of Ramik-Brown or doubling the concentration of diphacinone to 0.01% did not result in any additional control over the current formulation. Hand placement of ZP Rodent Bait AG at 1 to 3 lbs/A gave excellent control of voles. Place packs of ZP Rodent Bait AG were not opened at all sites, however, residual activity from apple activity data indicated that this product gave excellent control. Additional field and laboratory evaluations were suggested.
Low broadcast rates of Rozol at 9 lbs/A did not give adequate control of pine and meadow voles. The FMC Zinc Phosphide corn and oat formulation did not perform well even when compared to even lower rates of ZP Rodent Bait AG in broadcast trials.
The caching response of pine and meadow voles were found to differ markedly in one field experiment. Over 60% of the sites visited by pine voles had over 25 grams of blank pellets removed in a 24 hour period. Less than 2% of the meadow vole sites had 25 g removed in the same period of time.