Rodent Pest Management Research Articles

Farmers’ perspectives of rodent damage and rodent management in smallholder maize cropping systems of Southern Ethiopia

A survey was conducted in Chano area, Southern Ethiopia, to investigate farmers' viewpoints with regard to rodent pest problems. Farmers (n = 384) were interviewed using semi-structured questionnaire between October 2018 and January 2019. Pests were implied (51%) as the major constraints of cereal crop production followed by shifting to cash crops (20.6%), waterlogged farmlands (15.6%), infertile soils (8.6%) and insufficient rains (4.2%). Farmers experienced rodent outbreaks (83%) and identified maize (98%) as a crop most susceptible to rodent damage. Farmer suffered 23.5% average annual maize loss due to rodents. Being male (OR = 2.82, P < 0.05) and years spent in farming (OR = 1.13, P < 0.001) increased the likelihood of farmers' experience with rodent outbreaks. Seedling stage of maize was identified as the stage most susceptible to rodent damage (64.8%), followed by harvesting (19.3%) and maturity (15.9%) stages. When adjusted for other factors, a year increase in farming as an occupation decreased farmers' estimate of annual maize yield loss due to rodent damage by a coefficient of 0.04 (P < 0.05). An individual's experience (86.5%) was the major factor in deciding the type of rodent pest management. Application of rodenticides was the most frequently used (76%) rodent management method. We recommend awareness creation and extension support to the farmer community to reduce the reliance on toxic rodenticides and shift to community-based integrated rodent management approaches that would reduce the unacceptable damage levels.

Characteristics of Bandicota bengalensis burrows during different growth stages of wheat crop in Punjab

Burrowing is an activity used by rodents for resting, sleeping and food hoarding purposes and is affected by different abiotic and biotic factors. In the present study, an attempt has been made to describe the burrow structure of Bandicota bengalensis in relation to different crop stages of wheat crop. We observe that as the growth stages of wheat crop change from tillering to lean period, there is change in pattern of burrow structure by rodents. The length of burrow was maximum (200.80±2.84cm) during tillering stage and minimum (172.40±2.97cm) during lean period, whereas the depth of burrow was minimum (52.50 ±1.65cm) during tillering and maximum (68.90±2.83cm) in lean period to keep the environment of burrow optimum when mean soil moisture (%) and soil temperature recorded were 25.62%, 14.72°C and 14.88%, 25.84°C, respectively. The mean number of open ends, blind ends, number of nest chambers and number of burrow branches were highest during dough stage and lowest during lean period. Present study will help in development of policies that include strategies for rodent pest management i.e. for placing poison baits in burrows so that the rodent damage to crops may be reduced to a minimum level and farm income may be increased.

Adoption of rodent pest management strategies by farmers of district Ludhiana, Punjab

The present study was conducted to assess adoption of rodent pest management strategies by farmers in District Ludhiana, Punjab during the year 2017-18. Farmers belonging to three villages, namely Barewaal Dogra (maintenance area), Kutbewaal Gujran (neglected area) and Ladiyan Kalan (survey area) having land holding ranging from 2.0-32.0 acres were selected. The pre-dominant rodent pest species in area under study was Bandicota bengalensis followed by Tatera indica, Millardia meltada and Mus boodguga. Education and training was provided to farmers belonging to maintenance and neglected villages whereas free rodenticide baits were distributed among farmers of maintenance village only. In survey village, no such activity was performed and kept as reference area. KAP survey (Knowledge Aptitude and Practice) of farmers before imparting education during paddy crop period revealed similar rodent control practices being used by farmers in all the three selected villages. Subsequent KAP survey during wheat crop period for impact assessment revealed the sustainability of education and training already imparted during paddy crop period. About 41-92% increase in farmers observing recommended rodent control practices during crop production was noticed. So timely education and free rodenticide bait distribution are important factors responsible for adoption and sustainability of rodent control strategies by the farmers. Farmer can save food grains (33.09 kg paddy/acre and 36.39 kg wheat/acre) with an economic benefit (Rs. 500.09-575.66/acre) and cost: benefit ratio of 1: 36 to 1: 39 by using education, training and free rodenticides which will help in food security.

Ethanol and a chemical from fox faeces modulate exploratory behaviour in laboratory mice

Mice are macrosmatic animals that use olfaction as their main source of information toincrease fitness; they process predator cues to assess risk, and plants and fruit cues to find nutritionalresources and assess their quality or toxicity. In this study, we examined the effects of ethanol as an olfactory stimulus related to fruit rotting, against 2,4,5-trimethylthiazoline (TMT, a fox faeces compound), its native origin, the fox faeces and a negative control on avoidance, locomotor activity, and stress related behaviour, measured by the production of faecal boli. Our results showed that mice clearly avoided ethanol (P=<0.0001) and decreased their locomotor activity (P = 0.0076) when ethanol was present. The molecule 2,4,5-trimethylthiazoline (TMT), was the most avoided (P=<0.0001) and showed the lowest locomotor activity (P = 0.0004). Both treatments, ethanol (P = 0.0348) and TMT (P = 0.0084) increased the number of faecal boli.The clear avoidance and behavioural effects of ethanol in mice have direct implications in laboratory animal research, where it is used widely. This avoidance effect could elicit stressful situations and modify behavioural and physiological responses in mice housed in research facilities. In addition, this avoidance could be used as a non-lethal, inexpensive and non-toxic tool in rodent pest management. To explain these results, we suggest ethanol as a probable cue for fruit ripening, in the wild, this chemical cue could convey primordial information about the ripening state of fruits, allowing animals to avoid over-ripe, unhealthy fruits.

Corrigendum to: Rodent management issues in South Pacific islands: a review with case studies from Papua New Guinea and Vanuatu

Rodents are a key pest to agricultural and rural island communities of the South Pacific, but there is limited information of their impact on the crops and livelihoods of small-scale farmers. The rodent pest community is known, but the type and scales of damage to different crops on different islands are unknown. Knowledge about rodent pest management in other geographical regions may not be directly transferable to the Pacific region. Many studies on islands have largely focussed on the eradication of rodents from uninhabited islands for conservation benefits. These broadscale eradication efforts are unlikely to translate to inhabited islands because of complex social and agricultural issues. The livelihoods, culture and customs of poor small-scale farmers in the South Pacific have a large bearing on the current management of rodents. The aim of the present review was to describe the rodent problems, impacts and management of rodents on South Pacific islands, and identify gaps for further research. We compared and contrasted two case studies. The situation in Papua New Guinea is emergent as several introduced rodent species are actively invading new areas with wide-ranging implications for human livelihoods and conservation. In Vanuatu, we show how rodent damage on cocoa plantations can be reduced by good orchard hygiene through pruning and weeding, which also has benefits for the management of black pod disease. We conclude that (1) damage levels are unknown and unreported, (2) the impacts on human health are unknown, (3) the relationships between the pest species and their food sources, breeding and movements are not known, and (4) the situation in Papua New Guinea may represent an emergent crisis that warrants further investigation. In addition, there is a need for greater understanding of the invasive history of pest rodents, so as to integrate biological information with management strategies. Ecologically based rodent management can be achieved on Pacific Islands, but only after significant well funded large-scale projects are established and rodent ecologists are trained. We can learn from experiences from other locations such as Southeast Asia to guide the way.

Harnessing Population Genetics for Pest Management: Theory and Application for Urban Rats (Abstract)

Effective management of rodent pests requires an ecological understanding of how they move through their environment, and how those movements influence the invasion, persistence, or reinvasion of problematic colonies. Traditional methodologies used to describe rodent movement patterns, such as mark-recapture, are hindered by their time-consuming nature and limited geographic scope. As such, our understanding of how rodents interact with urban environments remains limited. Population genetic principles and tools have the capacity to greatly increase our understanding of rodent population dynamics, ecological relationships, and movements across space but this field is often unapproachable to non-scientist pest management professionals. In this paper we aim to promote collaborative and integrative rodent pest management by introducing relevant population genetic principles, providing examples of their applications in studies of urban brown rats, and proposing future initiatives that link scientific, private, and government entities. Using a densely-sampled brown rat population in the city of Vancouver, BC we show how genetic relationships among individual brown rats can be leveraged to understand the geographic distribution of genetic clusters (i.e., colonies), natural barriers to migration, and the spatial scale of dispersal. We describe how these results can be exploited by PMPs to directly inform the creation of management units and decrease the likelihood of rapid post-treatment reinvasion. Further, we discuss the difficulties inherent in population genetic studies and the potential for high-quality model sites to develop generalizable strategies. Overall, we hope to expand the toolbox of pest management professionals, foster collaboration, and move towards more informed and sustainable management strategies.

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

Rodents, including common voles (Microtus arvalis) and house mice (Mus musculus) cause immense pre-harvest and post-harvest losses. Therefore, developing methods that mitigate these losses while maintaining their role in ecosystems is a priority. Several plant secondary metabolites (PSM) which significantly reduce food intake of both species under laboratory conditions have been identified. However, before these can be used in rodent pest management, they must be tested under more natural conditions where other food sources are available. In this study, the odors of 4 PSMs were evaluated for their repellent effects in experiments conducted in semi-natural enclosures. Soil treated with PSMs or untreated soil (experimental control) was placed in an underground box containing food (rolled oats). We quantified the number of visits to each box and could demonstrate that all 4 PSMs reduced the number of visits to treatment boxes in both rodent species. For common voles the combination of methyl nonyl ketone + black pepper oil was the most repellent PSM. House mice made fewer visits to all PSM boxes; boxes with the anthraquinone were visited least. Furthermore, house mice consumed less food from boxes containing soil treated with all 4 PSMs. Our results suggest that PSMs are repellent in murid and microtine rodents under semi-field conditions. In addition, the future use of PSM odors for repelling both pest species, especially house mice, seems promising. Further investigations with other PSMs, different concentrations as well as alternative application methods are needed to repel common voles from attractive crops.

Effect of synthetic hormones on reproduction in Mastomys natalensis

Rodent pest management traditionally relies on some form of lethal control. Developing effective fertility control for pest rodent species could be a major breakthrough particularly in the context of managing rodent population outbreaks. This laboratory-based study is the first to report on the effects of using fertility compounds on an outbreaking rodent pest species found throughout sub-Saharan Africa. Mastomys natalensis were fed bait containing the synthetic steroid hormones quinestrol and levonorgestrel, both singly and in combination, at three concentrations (10, 50, 100 ppm) for 7 days. Consumption of the bait and animal body mass was mostly the same between treatments when analysed by sex, day and treatment. However, a repeated measures ANOVA indicated that quinestrol and quinestrol + levonorgestrel treatments reduced consumption by up to 45%, particularly at the higher concentrations of 50 and 100 ppm. Although there was no clear concentration effect on animal body mass, quinestrol and quinestrol + levonorgestrel lowered body mass by up to 20% compared to the untreated and levonorgestrel treatments. Quinestrol and quinestrol + levonorgestrel reduced the weight of male rat testes, epididymis and seminal vesicles by 60–80%, and sperm concentration and motility were reduced by more than 95%. No weight changes were observed to uterine and ovarian tissue; however, high uterine oedema was observed among all female rats consuming treated bait at 8 and 40 days from trial start. Trials with mate pairing showed there were significant differences in the pregnancy rate with all treatments when compared to the untreated control group of rodents.

A method for reducing environmental pollution by using essential oils in rodent pest management program.

Strong-smelling plant extracts, such as essential oils, have a variety of feeding effects on mammals. Considering current concerns over long-term health issues and environmental effects of chemicals, plant-based products with repellent or antifungal activities may represent good solutions for improvement of rodent pest control programs. The present study was therefore focused on examining the effects of bergamot, lavender, and thyme essential oils as additional bait components on daily intakes of cereal-based baits by wild house mice. Lavender essential oil, containing linalool and linalyl acetate as main components, and thyme essential oil with a prevailing thymol component had no effects on house mice diet. Bergamot essential oil, whose main components were linalool, limonene, and linalyl acetate, showed a repellent effect on house mouse diet.

Recovery of fertility in quinestrol-treated or diethylstilbestrol-treated mice: Implications for rodent management.

Fertility control is an alternative strategy to traditional culling for the management of rodent pests. Previous studies have demonstrated that quinestrol is a potential contraceptive for male rodents, but the recovery of fertility in quinestrol-treated rodents has not been evaluated. This study used C57BL/6J mice to evaluate the recovery rate of male fertility after the administration of quinestrol. Diethylstilbestrol (DES), a non-steroid estrogenic compound, was used for comparison. Different groups of mice were treated with 1 mg/kg quinestrol, 1 mg/kg DES, or castor oil separately for 7 days. These mice were then killed on days 8, 22 and 50 respectively. Our results indicated that the weight of epididymides and seminal vesicles decreased significantly on days 8 and 22 in quinestrol/DES-treated mice, with extensive histological changes in the seminiferous tubules. Sperm concentrations in the cauda epididymal fluid were significantly reduced on days 8 and 22 in both quinestrol and DES treatment groups and on day 50 for the DES, but not the quinestrol group. Further analysis revealed that DES-treated mice exhibited a higher proportion of abnormal sperm accumulation in the epididymis, indicating that the normal sperm transportation to the cauda epididymis was blocked. Our results indicate that the anti-fertility effects on male mice given quinestrol were of shorter duration than for those receiving DES at the dose of 1 mg/kg body weight.

Rodent management issues in South Pacific islands: a review with case studies from Papua New Guinea and Vanuatu

Rodents are a key pest to agricultural and rural island communities of the South Pacific, but there is limited information of their impact on the crops and livelihoods of small-scale farmers. The rodent pest community is known, but the type and scales of damage to different crops on different islands are unknown. Knowledge about rodent pest management in other geographical regions may not be directly transferable to the Pacific region. Many studies on islands have largely focussed on the eradication of rodents from uninhabited islands for conservation benefits. These broadscale eradication efforts are unlikely to translate to inhabited islands because of complex social and agricultural issues. The livelihoods, culture and customs of poor small-scale farmers in the South Pacific have a large bearing on the current management of rodents. The aim of the present review was to describe the rodent problems, impacts and management of rodents on South Pacific islands, and identify gaps for further research. We compared and contrasted two case studies. The situation in Papua New Guinea is emergent as several introduced rodent species are actively invading new areas with wide-ranging implications for human livelihoods and conservation. In Vanuatu, we show how rodent damage on cocoa plantations can be reduced by good orchard hygiene through pruning and weeding, which also has benefits for the management of black pod disease. We conclude that (1) damage levels are unknown and unreported, (2) the impacts on human health are unknown, (3) the relationships between the pest species and their food sources, breeding and movements are not known, and (4) the situation in Papua New Guinea may represent an emergent crisis that warrants further investigation. In addition, there is a need for greater understanding of the invasive history of pest rodents, so as to integrate biological information with management strategies. Ecologically based rodent management can be achieved on Pacific Islands, but only after significant well funded large-scale projects are established and rodent ecologists are trained. We can learn from experiences from other locations such as Southeast Asia to guide the way.

Yield and Income Effects of Ecologically-based Rodent Management in Mekong River Delta, Vietnam

Regression-based strategies along with propensity score matching (PSM) were used to assess the farm-level economic impact of community action (CA) strategies associated with ecologically based rodent management (EBRM). The paddy yield and real net income of rice farmer beneficiaries of the EBRM approach in An Giang Province, Mekong River Delta, Vietnam, were analyzed using panel data from 151 rice farmers. PSM along with the difference-indifference framework using the fixed-effect approach were found to be the most appropriate methods to evaluate the farm-level economic impact of the adoption of the CA strategies. The EBRM through CA did not replace what the farmers were doing, but rather built on their practices and incorporated a scientific basis by encouraging farmers to work together at key times of a cropping season. In terms of labor use for rodent control, CA only entailed an additional 0.3 man-days/ha for every CA. Normally, for a 40-hectare (ha) rice field, around 30 persons participated in each CA including men, women, and children. With two to three times done in a season, a total of 1 man-day/ha is as an additional labor for the whole season. The adoption of the EBRM through CA had a significant and positive impact on paddy yield and real net income of rice farmers. The mean paddy yield increased by 0.43-0.45 ton per ha and real net income of the beneficiaries increased by VND1.16–1.19 million/ha (approximately USD65-67/ha). These findings imply that the adoption of the CA strategies in rodent pest management as part of EBRM may not only have partly contributed to food security and increased household income of the rice farmer-beneficiaries but also to environmental improvement in these communities.

Structural elucidation of estrus urinary lipocalin protein (EULP) and evaluating binding affinity with pheromones using molecular docking and fluorescence study

Transportation of pheromones bound with carrier proteins belonging to lipocalin superfamily is known to prolong chemo-signal communication between individuals belonging to the same species. Members of lipocalin family (MLF) proteins have three structurally conserved motifs for delivery of hydrophobic molecules to the specific recognizer. However, computational analyses are critically required to validate and emphasize the sequence and structural annotation of MLF. This study focused to elucidate the evolution, structural documentation, stability and binding efficiency of estrus urinary lipocalin protein (EULP) with endogenous pheromones adopting in-silico and fluorescence study. The results revealed that: (i) EULP perhaps originated from fatty acid binding protein (FABP) revealed in evolutionary analysis; (ii) Dynamic simulation study shows that EULP is highly stable at below 0.45 Å of root mean square deviation (RMSD); (iii) Docking evaluation shows that EULP has higher binding energy with farnesol and 2-iso-butyl-3-methoxypyrazine (IBMP) than 2-naphthol; and (iv) Competitive binding and quenching assay revealed that purified EULP has good binding interaction with farnesol. Both, In-silico and experimental studies showed that EULP is an efficient binding partner to pheromones. The present study provides impetus to create a point mutation for increasing longevity of EULP to develop pheromone trap for rodent pest management.

Impact of spatio-temporal simulations of rat damage on yield of rice (Oryza sativa L.) and implications for rodent pest management

Rodents often damage crops throughout the growing season, from germination to harvest, thus making it difficult to understand the cumulative effects of rodent damage for crops such as rice that are able to partially compensate for damage. Compensation can make it difficult to understand the impact of variable rodent damage in terms of when the damage occurs, its severity and thus when, whether and how rodent pests should be controlled. The compensatory responses of rice to simulated rat damage carried out at different growth stages and at different spatial levels of severity showed that higher yield was recorded during the wet season in comparison to the dry season. However, yield loss was observed during all cropping stages for all levels of simulated damage for wet and dry season crops, with significant compensation noted at the transplanting [14 days after sowing (DAS)] and vegetative (45 DAS) stages. Only damage at the maturity (110 DAS) stage resulted in significant reductions in rice crop yield. Seasonal differences suggest water availability was an important factor that perhaps enhanced rice production. The ability of rice to compensate for early rodent damage could potentially reduce a farmer's perception of damage. However, failing to control rodents at these earlier crop growth stages could lead to increased rodent populations at the time of maturity when compensatory effects are limited.

Environmental factors and agronomic practices associated with Savi’s pine vole abundance in Italian apple orchards

The development of an integrated rodent pest management strategy requires the adoption of protocols that should be based on a good knowledge of species–habitat relationships. Vole damage to orchards has increased in Italy in recent decades, as new cultivation practices have been introduced, despite the use of rodenticides. To improve our understanding of factors influencing Savi’s pine vole abundance in Italian apple orchards, we monitored the relationship between environmental and agronomic variables and population densities. Vole population sizes were influenced by the abundance of voles in the neighbouring fields and the presence of kiwifruit orchards, usually not treated with rodenticides, bordering on apple orchards. The type of irrigation system had the strongest influence on vole abundance and flood-irrigated fields had fewer voles than drip-irrigated fields. Apple-tree age and tilling practices also had an influence on vole abundance. Our research provides evidence that vole populations are influenced mostly by agronomic practices and type and extension of fruit orchards. An integrated management strategy in the apple orchard district should include coordination in chemical treatments between farmers and the experimentation of flood irrigation and regular soil tillage management as a possible cost-effective way to reduce vole populations.

Rating the rat: global patterns and research priorities in impacts and management of rodent pests

Abstract We report the results of the first systematic assessment of global patterns and research priorities emerging in the field of rodent pest management. We carried out an extensive literature review targeted towards identifying the most relevant rodent pests, their impacts and the most common methods used to control them. We identified three disproportionally important pest species that are characterized by severe, generalist and geographically widespread impacts: the black rat Rattus rattus, the Norway rat Rattus norvegicus and the house mouse Mus musculus. Overall, only 7% of known rodent species may be considered pests. Scansorial (i.e. terrestrial and semi‐arboreal) and fossorial species are generally important as pests, while aquatic and arboreal species have only specific impacts. Impacts of rodent pests on arable crops were studied most, followed by impacts on ecosystems. Studies on arable crops were typical in countries with low net income and health expenditure, while the opposite was observed for studies on ecosystems. Poisons were the most commonly used control method, followed by traps and habitat management. The need to control rodent species is expanding, especially to protect ecosystems and public health. Unlike in other fields of pest management (e.g. insect control), in rodent control we are approaching new problems with old solutions; control strategies and methods have not kept pace with emerging impacts. The need to control a rodent pest species is higher when it is non‐native than within its original geographical range. The impact of a rodent species in its native range is a good predictor of the impact it may have in areas of introduction. Our review will contribute towards guiding researchers and stakeholders to focus research efforts and investments on a subset of species, and on new, less hazardous control techniques.

Habitat manipulation in lowland rice-coconut cropping systems of the Philippines-an effective rodent pest management strategy?

Reduction of vegetation height is recommended as a management strategy for controlling rodent pests of rice in South-east Asia, but there are limited field data to assess its effectiveness. The breeding biology of the main pest species of rodent in the Philippines, Rattus tanezumi, suggests that habitat manipulation in irrigated rice-coconut cropping systems may be an effective strategy to limit the quality and availability of their nesting habitat. The authors imposed a replicated manipulation of vegetation cover in adjacent coconut groves during a single rice-cropping season, and added artificial nest sites to facilitate capture and culling of young. Three trapping sessions in four rice fields (two treatments, two controls) adjacent to coconut groves led to the capture of 176 R. tanezumi, 12 Rattus exulans and seven Chrotomys mindorensis individuals. There was no significant difference in overall abundance between crop stages or between treatments, and there was no treatment effect on damage to tillers or rice yield. Only two R. tanezumi were caught at the artificial nest sites. Habitat manipulation to reduce the quality of R. tanezumi nesting habitat adjacent to rice fields is not effective as a lone rodent management tool in rice-coconut cropping systems.

Avian predators as a biological control system of common vole (Microtus arvalis) populations in north‐western Spain: experimental set‐up and preliminary results

Ecologically based rodent pest management using biological control has never been evaluated for vole plagues in Europe, although it has been successfully tested in other systems. The authors report on the first large-scale replicated experiment to study the usefulness of nest-box installation for increasing the breeding density of common kestrels (Falco tinnunculus) and barn owls (Tyto alba) as a potential biological control of common vole (Microtus arvalis) abundance in agricultural habitats in north-western Spain. The results show that: (1) population density of both predator species increased in response to both nest-site availability and vole density; (2) voles are a major prey for the common kestrels during the breeding period; (3) vole density during the increase phase of a population cycle may be reduced in crop fields near nest boxes. The installation of nest boxes provides nesting sites for barn owls and kestrels. Kestrel populations increased faster than in areas without artificial nests, and the common vole was one of their main prey during the breeding season. The results suggest that local (field) effects could be found in terms of reduced vole density. If so, this could be an environmentally friendly and cheap vole control technique to be considered on a larger scale.

Natal nest locations of the Asian house rat (Rattus tanezumi) in lowland rice–coconut cropping systems: a coconut penthouse or rice bunds with water frontage?

Context Rattus tanezumi is a serious crop pest within the island of Luzon, Philippines. In intensive flood-irrigated rice field ecosystems of Luzon, female R. tanezumi are known to primarily nest within the tillers of ripening rice fields and along the banks of irrigation canals. The nesting habits of R. tanezumi in complex rice–coconut cropping systems are unknown. Aims To identify the natal nest locations of R. tanezumi females in rice–coconut systems of the Sierra Madre Biodiversity Corridor (SMBC), Luzon, during the main breeding season to develop a management strategy that specifically targets their nesting habitat. Methods When rice was at the booting to ripening stage, cage-traps were placed in rice fields adjacent to coconut habitat. Thirty breeding adult R. tanezumi females were fitted with radio-collars and successfully tracked to their nest sites. Key results Most R. tanezumi nests (66.7%) were located in coconut groves, five nests (16.7%) were located in rice fields and five nests (16.7%) were located on the rice field edge. All nests were located above ground level and seven nests were located in coconut tree crowns. The median distance of nest sites to the nearest rice field was 22.5 m. Most nest site locations had good cover of ground vegetation and understorey vegetation, but low canopy cover. Only one nest location had an understorey vegetation height of less than 20 cm. Conclusions In the coastal lowland rice–coconut cropping systems of the SMBC, female R. tanezumi showed a preference for nesting in adjacent coconut groves. This is contrary to previous studies in intensive flood-irrigated rice ecosystems of Luzon, where the species nests mainly in the banks of irrigation canals. It is important to understand rodent breeding ecology in a specific ecosystem before implementing appropriate management strategies. Implications In lowland rice–coconut cropping systems, coconut groves adjacent to rice fields should be targeted for the management of R. tanezumi nest sites during the main breeding season as part of an integrated ecologically based approach to rodent pest management.

Efficacy of acute and anticoagulant rodenticide baiting in sugarcane fields of Punjab, India

The aim of this study was to recommend locality-specific rodent pest management techniques for sugarcane using acute and anticoagulant rodenticides during the months when maximum damage is inflicted on the crop in Punjab, India. Sugarcane crops were found to be infested with four rodent species namely: Bandicota bengalensis (Gray and Hardwicke); Mus booduga (Gray); Millardia meltada (Gray) and Golunda ellioti (Gray), with B. bengalensis being the most prevalent species (accounting for 69.45–83.36% of the total catch). Surveys in 11 villages of three districts of Punjab (India) revealed 19.12 ± 12.22% rodent damage to the sugarcane crop during the months of December–January. Rodenticide treatments were conducted in farmer's fields in two districts of Punjab from December 2003 to January 2007. The results revealed that, to protect the sugarcane crop from rodent damage during the months of December–January, the rodenticide treatment may be applied either: (1) by double-baiting with 2% zinc phosphide followed by 0.005% bromadiolone after 15d at 1 kg/ha each, or (2) by single-baiting with 0.005% bromadiolone at 2 kg/ha. The impact of rodenticide treatment in canefields was also evident in the adjoining wheat crop fields where the incidence of rodent damage was less (0.97–3.24%) than in the fields surrounding untreated canefields (3.53–6.22%).