Strategic baiting protocols for rodents in sugarcane : Final report STU033

Abstract

This research was undertaken to investigate the perceived problem of secondary poisoning risk to avian predators associated with the use of rodenticides in the Australian sugar industry. Although a minor component of the rodent integrated pest management strategy and used at relatively low levels, there is widespread public concern that their use can significantly impact raptor populations. At present, only anecdotal evidence of secondary poisoning events occurring in raptor populations are available and these relate to the use of Klerat® (active constituent: brodifacoum), a now de-registered rodenticide. Currently, two rodenticides are available for use in sugarcane crop, the acute toxicant Rattoff® (active constituent: 2.5 % zinc phosphide) and the first generation anticoagulant rodenticide Racumin® (active constituent: 0.037 % coumatetralyl). While laboratory trials indicate that raptors have a high toxic threshold to these rodenticides, trials conducted under laboratory conditions cannot reflect the complex processes which lead to secondary poisoning events that occur in the field. Given this, the objective of this project is to provide an ecologically-based field assessment of the risks that the use of rodenticides pose to avian predators in Australian sugarcane producing areas.