Sodium monofluoroacetate and alternative toxins for possum control

Abstract

Sodium monofluoroacetate (1080) is still an essential tool for possum control. We have reassessed the fate of this compound in the environment, and found no evidence of water contamination after large-scale possum control operations. The toxin is biodegradable in all living systems and will not accumulate in the food chain. Nevertheless, overreliance on a single toxin for a particular pest, such as 1080 for possum control, is unwise, and we are evaluating alternatives. Possums are susceptible to some non-anticoagulant toxins, including gliftor, cholecalciferol, calciferol, and alpha-chloralose. Of the anticoagulant toxins, brodifacoum is more effective than pindone. Integrated pen and field trials will determine the most cost-effective alternatives to 1080 for use in bait stations and for aerial application. Any alternative toxin will need to be subjected to the same scrutiny as 1080 for its environmental fate and impact on non-target species.

Review of the toxicity and impacts of brodifacoum on non‐target wildlife in New Zealand

“…Second-generation compounds such as brodifacoum induce death in most species after only a single dose (Eason et al 1994). The toxicity of brodifacoum varies both in mammals (Table 1, included for comparative purposes) and birds (Table 2).…”

“…comm.) and brushtail possums (Trichosurus vulpecula) (Brown 1993;Eason et al 1993). Two types of brodifacoum baits are used in New Zealand: a 15 g cereal-based wax block containing 50 ppm brodifacoum (Talon® 50WB), and a 2 g cereal-based pellet containing 20 ppm brodifacoum (Talon® 20P and Talon® Possum Bait).…”

The biochemical toxicology of 1,3-difluoro-2-propanol, the major ingredient of the pesticide Gliftor: The potential of 4-methylpyrazole as an antidote

“…It is reported to be palatable, effective against rodents (LD 50 for the rat 45.6 mg per kg body weight) (21) and brush-tailed possums (22,23), and has minimal environmental persistence (24). Apart from the observation that toxic doses of gliftor precipitate signs of poisoning similar to those seen in 1080 intoxication (cold extremities, ventricular fibrillation, and convulsions) (25) and a report that the administration of gliftor to rats decreases hepatic concentrations of S-adenosylmethionine and S-adenosylhomocysteine (26), the metabolic fate and mode of toxic action of the pesticide are largely unknown.…”

Secondary poisoning risks from 1080-poisoned carcasses and risk of trophic transfer—a review

“…To a large extent, non-target species will be protected by their ability to detoxify 1080, although the biochemical basis for tolerance and species variation is not clear (Twigg et al 1988;Twigg 1994). Food web transfer will be limited, as with each trophic level increase, the amount of 1080 present will be reduced given it does not readily bioaccumulate (Rammell 1993;Eason et al 1994c). This is in contrast to biomagnification risks seen from other anticoagulant pesticides .…”

“…A clear example of this risk is the elimination half-life of 1080 and brodifacoum in possum plasma*9 hours for 1080 (Eason et al 1994c) versus approximately 8 days for brodifacoum* and even longer for brodifacoum in possum liver (252 days; Eason et al 1996). A number of examples of contamination in wildlife and detrimental impacts on non-target populations from secondary and tertiary poisoning by brodifacoum exist (e.g.…”