Populations of invasive wild pigs (Sus scrofa) are increasing in many regions of the world, in particular the United States and Australia. Invasive wild pigs cause extensive damage to ecological resources and agriculture. Development and registration of a safe and humane toxic bait offers a practical and cost‐effective tool to control invasive species. Currently, no toxicants are approved for use on invasive wild pigs in the United States and those approved in Australia are under scrutiny because of concerns regarding humaneness and effects on nontarget species. We tested a newly formulated bait containing the micro‐encapsulated active ingredient, sodium nitrite (HOGGONE®; Animal Control Technologies Australia P/L, Victoria, Australia), that is considered humane and safer for nontarget species because it does not bioaccumulate. We examined palatability, lethality, and stability of the bait (i.e., fresh compared to 8‐month‐old bait) on groups of captive invasive wild pigs. We found HOGGONE® was a preferred food item, averaging 475 g of toxic bait consumed per animal during the first night offered. Consumption of HOGGONE® resulted in 95% mortality (53 of 56) in the treatment groups across 2 treatment nights. Most mortalities (98%) occurred during the first night the toxic bait was offered. Camera evidence suggested that deaths occurred within 3 hr post‐offering. The toxic bait was stable and effective up to 8 months post manufacture. Our results support current applications to register HOGGONE® for reducing damage from invasive wild pigs in the United States and Australia. Further research is required to evaluate HOGGONE® on free‐ranging invasive wild pigs using bait stations that exclude nontarget species. © 2017 The Wildlife Society.

Invasive feral swine (Sus scrofa) cause extensive damage to agricultural and wildlife resources throughout the United States. Development of sodium nitrite as a new, orally delivered toxicant is underway to provide an additional tool to curtail growth and expansion of feral swine populations. A micro-encapsulation coating around sodium nitrite is used to minimize detection by feral swine and maximize stability for the reactive molecule. To maximize uptake of this toxicant by feral swine, development a bait matrix is needed to 1) protect the micro-encapsulation coating so that sodium nitrite remains undetectable to feral swine, 2) achieve a high degree of acceptance by feral swine, and 3) be minimally appealing to non-target species. With these purposes, a field evaluation at 88 sites in south-central Texas was conducted using remote cameras to evaluate preferences by feral swine for several oil-based bait matrices including uncolored peanut paste, black-colored peanut paste, and peanut-based slurry mixed onto whole-kernel corn. These placebo baits were compared to a reference food, whole-kernel corn, known to be readily taken by feral swine (i.e., control). The amount of bait consumed by feral swine was also estimated using remote cameras and grid boards at 5 additional sites. On initial exposure, feral swine showed reduced visitations to the uncolored peanut paste and peanut slurry treatments. This reduced visitation subsided by the end of the treatment period, suggesting that feral swine needed time to accept these bait types. The black-colored peanut paste was visited equally to the control throughout the study, and enough of this matrix was consumed to deliver lethal doses of micro-encapsulated sodium nitrite to most feral swine during 1–2 feeding events. None of the treatment matrices reduced visitations by nontarget species, but feral swine dominated visitations for all matrices. It was concluded that black-colored peanut paste achieved satisfactory preference and consumption by feral swine, and no discernable preference by non-target species, compared to the other treatments.

Registration is a necessarily sophisticated evaluation process applied to vertebrate pesticide products. Although conducted to minimise any potential impacts upon public health, the environment and food production, the allencompassing process of registration can stifle innovation. Vertebrate pesticides are rarely used to control pest animals in food crops. In contrast to agrochemicals, relatively small amounts of vertebrate pesticides are used (50.1%), usually in solid or paste baits, and generally by discrete application methods rather than by broad-scale spray applications. We present a hierarchy or sliding scale of typical data requirements relative to application techniques, to help clarify an evolving science-based approach which focuses on requiring data to address key scientific questions while allowing waivers where additional data have minor value. Such an approach will facilitate the development and delivery of increasingly humane, species-targeted, low residue pesticides in the New World, along with the phasing out of less desirable chemicals that continue to be used due to a lack of alternatives.

Data from this study suggest no risks of secondary poisoning for non-target species (including humans) that consume muscle, liver, or eyes of invasive wild pigs poisoned with a MESN toxic bait. More species-specific testing for scavengers that consume digestive tract tissues and undigested bait is needed to reduce uncertainty about these potential risks. © 2017 Society of Chemical Industry.

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