Increasing acceptance and efficacy of zinc phosphide rodenticide baits via modification of the carbohydrate profile

Abstract

Toxicant coated grain-based baits are widely used to control rodent pests throughout the world, but where alternative food sources are available, bait acceptance and efficacy are often less than optimal. In an attempt to develop baiting strategies to increase bait acceptance and efficacy of zinc phosphide-coated baits, a sugar-enhanced rolled oat based zinc phosphide bait was evaluated. With pre-baiting, 100 and 60% mortality was achieved for California and Belding's ground squirrels, respectively. A series of twochoice tests with a variety of potential bait matrices indicated that rolled oats was a desirable base matrix for both species but the lecithin sticker negatively impacted bait acceptance by Belding's ground squirrels.

Field evaluation of some bait additives against Indian crested porcupine (Hystrix indica) (Rodentia: Hystricidae)

“…However, when saccharin was used in a concentration of 2%, there was no statistically significant increase in the consumption of the bait, yet a general trend of increasing acceptability of the bait persisted throughout the experiment. Sweeteners have been reported to have different values as bait additives for different rodent species, improving bait palatability in field rodents [Microtus californicus (Peale, 1848)] and other species of rats and mice (Rao & Prakash 1980;Yamaguchi 1995;Shumake et al 1997;Johnston et al 2005), whereas no such study is available on the Indian crested porcupine. Based upon possible acceptance of sweeteners by rats and mice, molasses has been used as an additive at a concentration of 5% in cracked maize (Khan et al 2006;Khan & Mian 2008) and broken rice and wheat flour (Pervez 2006) for successful poison baiting of Indian crested porcupine in different tracts of Pakistan.…”

“…Only 1 additive was tested at a time and the test ran for 7 days. At the end of each test a 7-10 day interval was allowed to nullify the effect of the previous possible acclimatization (Johnston et al 2005). In this way, the same burrows were repeatedly used to test different combinations of various bait additives.…”

“…These were common salt (crude rock salt, available from local markets, mined from the Khewra Salt Mine System), fish meal (crude form available from the local market mainly as an ingredient to constitute poultry feed), bone meal (leg bone of goat purchased from local markets and ground to a powdered form using anelectric grinder), saccharin (Saccharin Soluble, Choheung Chemical, Seoul, Korea), yeast powder (Instant Yeast, Saf-Instant, S. I. Lesaffre, 59703, Marcq, France), egg shell powder (egg shells collected from bakeries and blended to a powdered form using an electric blender), egg yolk (freshly prepared from poultry eggs purchased from the local market), mineral oil (heavy white oil, MP, Biomedicals, California, USA), peanut butter (Crown Products, Metairie, Louisiana, USA) and coconut oil (coconut purchased from the local market and oil extracted using local commercial oil expellers) were used in 2 and 5% concentrations to test their potentials to enhance bait consumption. All the above mentioned bait additives have been tested in bait for the control of rats and mice in different parts of the world, including Pakistan (Rao & Prakash 1980;Ahmad et al 1994;Yamaguchi 1995;Shumake et al 1997;Robards & Saunders 1998;Jacob et al 2003;Johnston et al 2005;Pervez 2007) but never tested for their potential in enhancing the bait acceptance against porcupine, apart from a sweetener (molasses), which increased the consumption of the bait (Khan et al 2006;Khan & Mian 2008).…”

“…Although some studies are available on the food preference of Indian crested porcupine under field conditions (Mushtaq et al 2009(Mushtaq et al , 2010, comparative studies are lacking on bait efficacy enhancement through incorporating various bait additives. Several studies are available where the bait consumption has been enhanced by incorporating different additives for various rat species, such as Rattus norvegicus (Berkenhout, 1769), Rattus rattus (Linnaeus, 1758), Mus musculus Linnaeus, 1758 and Bandicota bengalensis (Gray and Hardwicke, 1833) (Shafi et al 1992(Shafi et al , 1993Yamaguchi 1995;Shumake et al 1997;Pervez et al 2000Pervez et al , 2003Johnston et al 2005;Pervez 2007).…”

Evaluation of some additives for acceptability with zinc phosphide bait against rodent

“…Some studies have been performed to upgrade the present rodent control tactics to make it more efficient through mixing different locally available palatable food or bait additives (Pervez et al, 2005;Johnston et al, 2005;Naeem et al, 2011). ElGawad and Ali (1982 a) improved the efficiency of zinc phosphide bait by adding molasses to crushed maize bait.…”