Plant Secondary Metabolites as Rodent Repellents: a Systematic Review

Abstract

The vast number of plant secondary metabolites (PSMs) produced by higher plants has generated many efforts to exploit their potential for pest control. We performed a systematic literature search to retrieve relevant publications, and we evaluated these according to PSM groups to derive information about the potential for developing plant-derived rodent repellents. We screened a total of 54 publications where different compounds or plants were tested regarding rodent behavior/metabolism. In the search for widely applicable products, we recommend multi-species systematic screening of PSMs, especially from the essential oil and terpenoid group, as laboratory experiments have uniformly shown the strongest effects across species. Other groups of compounds might be more suitable for the management of species-specific or sex-specific issues, as the effects of some compounds on particular rodent target species or sex might not be present in non-target species or in both sexes. Although plant metabolites have potential as a tool for ecologically-based rodent management, this review demonstrates inconsistent success across laboratory, enclosure, and field studies, which ultimately has lead to a small number of currently registered PSM-based rodent repellents.

Like or dislike: Response of rodents to the odor of plant secondary metabolites

“…Few studies have been conducted in outdoor enclosures or in the field to examine the effect of plant-derived repellents on the feeding behavior of rodents (Bäumler et al 1990;Witmer et al 1998;Willoughby 2011;Fischer et al 2013b). The translation of laboratory bioassays into effective operational systems through testing in semi-field or field conditions is missing or has been problematic (Hansen et al 2016b). We investigated whether odors of PSM, which had proven repelling properties in controlled bioassays, are effective in a semi-natural environment in two rodent species.…”

The elusive search for an effective repellent against voles: an assessment of anthraquinone for citrus crops

“…Although agricultural producers require effective rodent repellents, most previous results from field-tested products have not been overly promising (Hansen et al 2016a). Anthraquinone appears to be an exception, as it has generally tested well against voles in lab investigations (Hansen et al 2015;Werner et al 2016;but Hansen et al 2016b see for lack of efficacy with male common voles Microtus arvalis) and in our field-based trials.…”

“…There is a wide array of secondary plant metabolites that act as anti-feedants to mammals (reviewed by Hansen et al 2016a). Although repellents have sometimes shown promise in lab studies (e.g., Salatti et al 1995;Witmer et al 2000;Curtis et al 2002;Hansen et al 2015Hansen et al , 2016b, repellents have often failed to prove highly effective in field trials (Merwin et al 1999;Hansen et al 2016a).…”

“…There is a wide array of secondary plant metabolites that act as anti-feedants to mammals (reviewed by Hansen et al 2016a). Although repellents have sometimes shown promise in lab studies (e.g., Salatti et al 1995;Witmer et al 2000;Curtis et al 2002;Hansen et al 2015Hansen et al , 2016b, repellents have often failed to prove highly effective in field trials (Merwin et al 1999;Hansen et al 2016a). Specific reasons for failure are generally unknown, but are likely related to the availability of cover and food sources, and a need for frequent re-application of volatile compounds or washing away following rainfall and irrigation events (Merkens et al 1991;Mason 1998;Conover 2002;Hansen et al 2016a).…”

The Cost of Roaming Free: Assessing the Effects of Plant Secondary Metabolites on Diet Selection and Nutritional Condition in a Free-Ranging Generalist Herbivore

“…Similarly, browsing by moose (Alces alces) on two species of willow (Salex phylicifolia and S. myrsinifolia) resulted in the induction of certain phenolic compounds which were subsequently selected against by moose during return visits to these same plants (Shiojiri et al 2015;Karban et al 2016). Many studies indicate that monoterpenes are used as a direct defense against both vertebrate and invertebrate herbivores (Gong and Zhang 2014;Hansen et al 2016). Tannins are phenolic compounds that can bind to dietary protein (Degabriel et al 2008;Moore et al 2010).…”