Anticoagulants are the most frequently used rodenticides at the global scale. Because of their persistency, bioaccumulation and potential for secondary intoxication, they have faced increasing legislative regulations. Recently, the European Union Regulation (EU) 2016/1179 resulted in the production and application of rodenticides with nearly half dose (<30 ppm) of anticoagulants. However, published data on the biological efficacy of rodenticides with decreased doses are scarce in the EU. Therefore, this work compared the efficacy of the original high-dose (50 ppm) and new low-dose (25 ppm) brodifacoum-based baits in the offspring of wild-caught house mice (Mus musculus L.). In the no-choice laboratory feeding tests, 100% animals died in all treated groups and 0% died in the control groups. The achieved time to death did not differ between the original and low-dose baits across both types of feeding trials/regimes. The low-dose baits (25 ppm) were consequently tested under field conditions in two populations showing 95.7% and 99.8% efficacy. The obtained results highlighted the good efficacy of the new baits based on low-dose brodifacoum in non-resistant mouse populations. However, further validation is required regarding the remaining anticoagulant compounds and resistant rodent populations.

The integrated management of a serious agricultural pest, the common vole (Microtus arvalis), should be based on modern and empirically proven approaches. The aim of this paper was to map the historical development of the monitoring and control practices of the common vole in the Czech Republic (CR) territory. Published records of vole population outbreaks and heavy crop damage have been documented in the Czech literature since the turn of the 20th century, and even in crops planted in highly fragmented and diversified agricultural landscapes. In the CR, systematic state monitoring was introduced in 1955. In the 1930’s, there were more than 100 various rodent preparations against the common vole, which were formulated as smoke generators, gases, baits, dusts, toxic mushy mass, and insecticide sprays. Currently, there are only six preparations with three active ingredients registered in the CR. Zinc phosphide is the only active ingredient that has been used from the 1940s to the present, whereas anticoagulants were banned for vole control in 2011 owing to the high environmental risks. The poisoning of nontarget animals by rodenticides is not a new phenomenon tied to synthetic pesticides; poisoning by botanical extracts (strychnine) was documented more than 100 years ago. This review may provide both historical lessons for current practice and new incentives for future research.

Insecticides and rodenticides form the basis of integrated pest management systems worldwide. As pest resistance continues to increase and entire groups of chemical active ingredients are restricted or banned, manufacturers are looking for new options for more effective formulations and safer application methods for the remaining pesticide ingredients. In addition to new technological adaptations of mainstream formulations in the form of sprays, fumigants, and dusts, the use of gel formulations is becoming increasingly explored and employed. This article summarizes information on the current and potential use of gel (including hydrogel) and paste formulations against harmful arthropods or rodents in specific branches of pest management in the agricultural, food, stored product, structural wood, urban, medical, and public health areas. Due to the worldwide high interest in natural substances, part of the review was devoted to the use of gels for the formulation of pesticide substances of botanical origin, such as essential or edible oils. Gels as emerging formulation of so called “smart insecticides” based on molecular iRNA disruptors are discussed.

House mouse (Mus musculus) is a cosmopolitan pest in agricultural facilities, commodity stores and rural and urban environments. It is regularly controlled by anticoagulant-based baits. Since the number of registered active ingredients is limited, the producers are trying to develop new formulations with increased tamper-resistance, attractiveness and palatability. Reliable and economical methods for laboratory screening/testing are needed. Therefore, this work compared simple no-choice with more economically demanding choice feeding tests for laboratory evaluation of efficacy of rodenticide anticoagulant-based preparations in wild populations of house mouse. We analyzed mice survival and bait intake of the various rodenticide commercial preparations differing in a toxic active substance (warfarin, bromadiolone, brodifacoum, difethialone) and nontoxic food lure components. In most cases, we found insignificant differences in survival of house mice treated with eight test baits within the no-choice and choice feeding tests. We rejected the tested hypothesis that there would be significant differences in all tested preparations for two different testing approaches.

Despite the widespread use of anticoagulant rodenticides in baits for controlling commensal rodent pests, their application is problematic due to secondary intoxication and increasing resistance. In contrast to studies on Western European house mice (Mus musculus domesticus), few resistance studies have focused on Eastern European house mice (M. musculus musculus), which have a western distribution boundary in the Czech Republic. This study newly analysed the VKORC1 gene in M. m. musculus field populations from Czech farms and grain stores and identified a nonsynonymous mutation Tyr139Phe. This mutation was common throughout the Czech Republic and was present in 80.2% of the 86 individuals sampled. Additionally, all individuals exhibited a genotype with three synonymous mutations specific to the subspecies M. m. musculus. The functional (mortality–survival) response of the Tyr139Phe mutation was validated in a laboratory choice feeding test using bromadiolone-based bait, where all resistant homozygous individuals survived, while all susceptible mice died, with a mean survival of 6.9 days.

Anticoagulants are widely used as potent cumulative rodenticides; however, they are also associated with adverse environmental effects, such as intoxication of non-target animals. To ensure user safety, in the EU the use of anticoagulants containing active substances of > 30 ppm is restricted to professionals as these substances are toxic to reproduction Kat.1 A or B. Therefore, new products with < 30 ppm anticoagulant substance have been developed and registered. While the biological efficacy of these new products has been evaluated, the effect of their application on liver residues in targeted rodents was not examined before product introduction to the market. Our laboratory no-choice study on wild brown rats (Rattus norvegicus) showed that baits with high (50 ppm) and low (25 ppm) brodifacoum concentrations (with identical nontoxic cereal-based food components) presented 100% efficacy, although the 25 ppm bait exhibited significantly higher palatability and 4.5 times higher liver residues. Rats consumed 13.6 and 167.7 g of the 50 and 25 ppm baits, respectively, which corresponded to 3.16 and 14.91 μg/g of brodifacoum liver residues at their time of death. The experiments demonstrated that a decreased concentration of brodifacoum anticoagulant in rodenticide baits may lead to greater accumulation in rodent liver, thus indicating the urgent need to perform a detailed study of the environmental risks of low-concentration anticoagulant baits.