Interactions between rodents and weeds in a lowland rice agro-ecosystem: the need for an integrated approach to management

The complete mitochondrial genome and phylogenetic analysis of Rattus tanezumi (Niethammer, 1975), captured from North China

Rattus tanezumi (Niethammer, 1975) is one of the commensal rodent species in South China. With the development of transportation and climate change, R. tanezumi has gradually migrated north and become the dominant rat species for the past few years. In this study, we assembled a complete mitochondrial genome of R. tanezumi, captured from North China. The mitogenome contains 16,307 nucleotide pairs, including 13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes, as well as one non-coding control region. Based on whole mitogenome phylogenetical analysis showed that R. tanezumi captured from North China had a close phylogenetic relationship with that from Japan and South Korea. These findings are valuable for further studies on the evolution, genetic diversity, and taxonomy of Asian commensal rodent.

Shrews Under-Represented in Fruit Farms and Homesteads

Shrews are a less studied group of small mammals than rodents. Between 2018 and 2022, we surveyed 23 sites in Lithuania, including natural and anthropogenic habitats, with the aim to assess the proportion of Soricidae in small mammal communities and their diet based on stable isotope analysis. The average representation of Soricidae was 3.1%, about half the long-term average in other habitats in the country. The highest proportions were in meadows and farmsteads, at 4.9% and 5.0% respectively. Shrews were not trapped on farms or in young orchards, and their relative abundance was very low in intensively managed orchards (0.006 individuals per 100 trap days). Neomys fodiens and N. anomalus were unexpectedly found in homesteads, including in outbuildings. Sorex araneus and S. minutus had similar diets. The trophic carbon/nitrogen discrimination factor between invertebrates and shrew hair was 2.74‱/3.98‱ for S. araneus, 1.90‱/3.78‱ for S. minutus in the orchards. The diet of N. fodiens and N. anomalus at the homesteads requires further investigation. We propose that the under-abundance of shrews may be due to contamination by plant protection products and a lack of invertebrates under intensive agricultural practices.

Assessing animal welfare impact of fourteen control and dispatch methods for house mouse (Mus musculus), Norway rat (Rattus norvegicus) and black rat (Rattus rattus)

Population control of the house mouse (Mus musculus), Norway rat (Rattus norvegicus) and black rat (Rattus rattus) is common practice worldwide. Our objective was to assess the impact on animal welfare of lethal and non-lethal control methods, including three dispatch methods. We used the Sharp and Saunders welfare assessment model with eight experts scoring eleven control methods and three dispatch methods used on the three species. We presumed the methods were performed as prescribed, only taking into account the effect on the target animal (and not, for example, on non-target catches). We did not assess population control efficacy of the methods. Methods considered to induce the least suffering to the target animal were captive-bolt traps, electrocution traps and cervical dislocation, while those with the greatest impact were anticoagulants, cholecalciferol and deprivation. Experts indicated considerable uncertainty regarding their evaluation of certain methods, which emphasises the need for further scientific research. In particular, the impact of hydrogen cyanide, chloralose and aluminium phosphide on animal welfare ought to be investigated. The experts also stressed the need to improve Standard Operating Procedures and to incorporate animal welfare assessments in Integrated Pest Management (IPM). The results of our study can help laypeople, professionals, regulatory agencies and legislators making well-informed decisions as to which methods to use when controlling commensal rodents.

Rice pests in the Republic of Benin: farmers' perceptions, knowledge and management practices

BACKGROUND

Rice (Oryza spp) is one of the most consumed cereals in the Republic of Benin. However, rice production is threatened by various pests, which lead to important yield losses. For the development of integrated management strategies responding to the farmers' realities, it is important to document their perceptions, knowledge and management of rice pests. Surveys involving 418 rice farmers to 21 ethnic groups through 39 villages were performed using rural appraisal tools.

RESULTS

Farmers perceived birds, specifically weavers as the most important rice pests. The surveyed farmers also identified the variegated grasshopper, Zonocerus variegatus L. and rice brown leaf spots [Curvularia lunata (Wakker) Boedijn] as the main pests in the northern region, the pink stem borer, Sesamia calamistis Hampson and rice blast (Magnaporthe grisea (Hebert) Barr) in the southern region, and Z. variegatus and rice yellow mottle virus (genus Sobemovirus) in central Benin. The most important rice storage constraint was rodent attacks and the surveyed farmers proposed 13 key solutions to minimize constraints related to rice storage. Among various pest control methods recorded, farmers used mainly synthetic chemical pesticides. However, the Beninese National Pesticide Management Committee (CNGP) does not recommend most of pesticides used by farmers for rice protection (prohibited pesticides or intended for the protection of other crops). Farming experience, family size, region and number of observed pests have significantly influenced farmers' decision to use pesticides.

CONCLUSION

The rice pests perceived by farmers as important vary significantly across regions. These results suggest that integrated pest management programmes which target rice pests accounting for these regional differences will be more effective. The identified variables that influence the use of pesticides must be taken in account in the development of strategies which will encourage farmers to use ecofriendly pest management.

Rodent management and cereal production in Asia: Balancing food security and conservation

Rodents present a major problem for food security in Asia where smallholder farming families are particularly vulnerable. We review here recent developments in the biology and management of rodent pests in cereal cropping systems in Asia. The past decade has seen a strong focus on ecologically-based rodent management (EBRM), its adoption in field studies significantly increased rice yields (6-15%) and income (>15%) in seven Asian countries. EBRM principles have also been successfully applied to maize in China. We provide case studies on EBRM in Cambodia, on interactions between rodent pests and weeds, and on the importance of modified wetlands for biodiversity and rodent pest management. Knowledge on post-harvest impacts of rodents is increasing. One research gap is the assessment of human health impacts from a reduction of rodent densities in and around houses. We identify 10 challenges for the next decade. For example, the need for population modelling, a valuable tool missing from our toolbox to manage rodent pests in cereal systems. We also need to understand better the interactive effects of cropping intensification, conservation agriculture and climate change. Finally, new management approaches such as fertility control are on the horizon and need to be considered in the context of smallholder cereal farming systems and mitigating health risks from zoonotic diseases associated with rodents. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.