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Botany, New Zealand

Eason C.T.,Cawthron Institute | Eason C.T.,Lincoln University at Christchurch | Miller A.,Lincoln University at Christchurch | Miller A.,University of British Columbia | And 2 more authors.
New Zealand Journal of Ecology

Para-aminopropiophenone (PAPP) paste was approved as a stoat control agent in New Zealand by the Environmental Protection Authority in August 2011 and for feral cat control in November 2011. PAPP was originally researched in Europe and the USA as treatment for cyanide and radiation poisoning. Over the last 10 years, our research has focused on several factors, including determining its toxicity to predators, field effectiveness for controlling stoats and feral cats, animal welfare profile, toxicology, ecotoxicology, and understanding and reducing non-target risks. PAPP has been developed specifically for the control of stoats and feral cats because of the special sensitivity displayed by these species. Its toxicity is mediated by the induction of methaemoglobinaemia (the ferric state of haemoglobin). Normally, methaemoglobin levels in the blood are below 1%. Levels of methaemoglobin in the blood above 70% are usually fatal, creating a lethal deficit of oxygen in cardiac muscle and the brain. In stoats and feral cats, death after a lethal dose usually occurs within 2 h after eating bait, with clinical signs first appearing in 10 to 20 min for stoats and at around 35 min for cats. Animals become lethargic and sleepy before they die, hence PAPP is relatively humane. A simple antidote exists, namely methylene blue. Further, birds display a lack of toxicity to PAPP when compared with other vertebrate pesticides. A paste containing 40% PAPP has been developed for use in meat baits in New Zealand. A toxic dose for stoats and feral cats is achieved when pea-sized amounts of paste are delivered in 10-20 g meat baits. When meat baits containing PAPP are applied in bait stations in field settings, stoat and feral cat numbers can be rapidly reduced. However, there has been limited practical experience with PAPP to date, especially when compared with alternative tools such as traps or sodium monofluoroacetate (1080) baits. Additional practical experience should enable the effective use of PAPP as a tool to help protect native species from introduced predators. In the future, PAPP will be developed in long-life bait and in a resetting toxin delivery system. © New Zealand Ecological Society. Source

Jay-Smith M.,University of Auckland | Murphy E.C.,Lincoln University at Christchurch | Shapiro L.,Lincoln University at Christchurch | Shapiro L.,Connovation Ltd | And 4 more authors.

Norbormide [5-(α-hydroxy-α-2-pyridylbenzyl)-7-(α-2-pyridylbenzylidene)-5-norbornene-2,3-dicarboximide] (NRB, . 1), an existing but infrequently used rodenticide, is known to be uniquely toxic to rats but relatively harmless to other rodents/mammals. However, as an acute vasoactive, NRB has a rapid onset of action which makes it relatively unpalatable to rats, often leading to sub-lethal uptake/accompanying bait shyness. It is recognized that the pharmacological profile of NRB is highly sensitive to its stereoisomeric composition, yet no comprehensive endeavor has been made to impart any stereochemical control in its manufacture. The effect of temperature/concentration/reaction solvent/Lewis acid on the Diels-Alder synthesis of NRB is investigated. An attempted stereoselective synthesis of key NRB precursor 2-fulvenylmethanol . 4 is also described. Palatability/efficacy data in rats is reported for novel NRB batches . 1a-1e. Disappointingly, given the level of stereocontrol now available in the synthesis of NRB as a result of this research, no clear relationship between stereoisomeric composition and palatability was observed. © 2016 Elsevier Ltd. Source

Eason C.T.,Lincoln University at Christchurch | Eason C.T.,Connovation Ltd | Shapiro L.,Connovation Ltd | Hix S.,Connovation Ltd | And 5 more authors.
Wildlife Research

Context. Control of mammals is a controversial area and ecological and ethical justification is needed, with consideration of animal welfare being increasingly important. Australia and New Zealand are facing resistance to the continued use of sodium fluoroacetate (1080) because of its questionable humaneness, relative to cyanide, as well as other non-intended impacts. Wallabies are sometimes deemed unwanted pests requiring control in both Tasmania and New Zealand. We consider there is an ethical obligation to find humane tools and alternatives to 1080 for wallaby control. Aims. Two studies on captive animals were undertaken to assess the effectiveness and humaneness of Feratox cyanide pellets for culling Dama wallabies (Macropus eugenii) and Bennett's wallabies (Macropus rufogriseus). Methods. Cyanide pellets were presented in palatable non-toxic bait to 20 Dama and 24 Bennett's wallabies individually housed in spacious pens. Following ingestion of the toxic pellets by the wallabies, the effects of cyanide on these animals were closely observed. Key results. In all, 18 of 20 Dama wallabies presented with a pellet died. The mean time from cracking a cyanide pellet to unconsciousness was 7.7min, and 13.5min to death. In the separate trial of 24 Bennett's wallabies, 23 of those cracked at least one Feratox pellet in their mouth and died. The mean time from cracking a pellet to unconsciousness was 14min, and the time to death was 22min. In both studies, cyanide induced toxicosis and death occurred rapidly. The onset of symptoms and effects were similar to those previously reported in possums following ingestion of cyanide. Conclusions. Feratox has a short interval from onset of symptoms to unconsciousness in wallabies, with few undesirable signs from the welfare perspective. Implications. Public support is one of several factors influencing the choice of toxins. Toxin use for pest control will be sustained only if the control tools used are humane. On that basis, cyanide offers a preferred alternative to other vertebrate toxins, including 1080, for the control of wallabies. © CSIRO 2010. Source

Eason C.T.,Lincoln University at Christchurch | Eason C.T.,Connovation Ltd | Hix S.,Connovation Ltd | Macmorran D.B.,Connovation Ltd
Integrative Zoology

The endemic fauna of New Zealand evolved in the absence of mammalian predators and their introduction has been responsible for many extinctions and declines. Introduced species including possums (Trichosurus vulpecula Kerr), ship rats (Rattus rattus L.) and stoats (Mustela erminea L.) are targeted to protect native birds. Control methodologies currently rely largely on labor-intensive trapping or the use of increasingly unpopular poisons, or poisons that are linked with low welfare standards. Hence, the development of safer humane predator toxins and delivery systems is highly desirable. Para-aminopropiophenone (PAPP) is being developed as a toxin for feral cats (Felis catus L.) and stoats. Carnivores appear to be much more susceptible to PAPP than birds, so it potentially has high target specificity, at least in New Zealand. Pen trials with 20 feral cats and 15 stoats have been undertaken using meat baits containing a proprietary formulation of PAPP. A PAPP dose of 20-34 mg kg -1 was lethal for feral cats and 37-95 mg kg -1 was lethal for stoats. Our assessments suggest that PAPP, for the control of feral cats and stoats, is a humane and effective toxin. PAPP causes methaemoglobinaemia, resulting in central nervous system anoxia, lethargy and death. © 2010 ISZS, Blackwell Publishing and IOZ/CAS. Source

Shapiro L.,Connovation Ltd | Shapiro L.,Lincoln University at Christchurch | MacMorran D.,Connovation Ltd | Ross J.,Lincoln University at Christchurch | And 2 more authors.
New Zealand Journal of Ecology

In New Zealand we need to develop new control tools for the overabundant brushtail possum, which is an agricultural and environmental pest. In this study we evaluated the performance of a new microencapsulated zinc phosphide (MZP) paste (1.5% w/w nominal conc.) in a captive study and at six North Island field sites. In the captive study 14 out of 16 possums fed MZP paste bait died (87.5% kill ± 8.3% SE) with death occurring on average 165.4 minutes (± 5.5 SE) after first eating the bait. At all field sites relative possum abundance was estimated using a residual trap catch index, and contractors were able to choose their preferred ground-control technique. Pre-feeding non-toxic paste (using 200–320 g/ha) was carried out over 2 weeks with at least one topup after 7 days. Toxic bait was then deployed using the same baiting regime, and the average decline in possum abundance at the field sites was 82.2% (± 3.2% SE). This trial demonstrates that experienced contractors can get good kills using MZP and a refinement of best practice techniques could further improve control efficacy. © New Zealand Ecological Society. Source

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