Mammalian pest problems in organic pig farming, preventive measures and control

Organic pig farming includes having pigs in open fields with relatively close contact to the wild fauna. The risk of transmission of parasites and diseases to the pigs is therefore higher than in traditional pig farming with pigs under strict control in indoor pigsties. Newborn and sucking pigs are also exposed to predators that may cause losses to the farmers. A general trend in organic farming is to avoid the use of pesticides. There is therefore a need for effective preventive measures and control methods that are acceptable to the organic farmers. As a first step in a project for developing strategies for pest management in organic pig farming we conducted a questionnaire survey in Denmark. The farmers were asked questions about what they considered problems arising from the natural environment. They were also asked to describe how they offered fodder and water, which types of huts they used etc. The surroundings should be described regarding factors that were thought to influence the natural fauna, such as e.g. distance to quickset hedges, forests, streams and watercourses. The results of the survey showed that rats and smaller rodents (mice and voles), foxes and hares were the most frequently occurring mammals in the fields with pigs. The farmers considered rats and foxes as causing the most important (pest) problems. Occurrence of rats is reported significantly more frequently in organic pig farming than in traditional pig farming in open fields. The answers given by the farmers were analysed as to possible relationships between occurrence of / problems with rodents and the practice regarding the pig farming. There was a significant positive correlation between occurrence of rats, smaller rodents and foxes. Use of automatic feeding systems and open water trays, and having stacks of hay and straw in the fields were all factors that were significantly positively correlated with the occurrence of rats and smaller rodents. The occurrence of smaller rodents was negatively correlated with the use of huts with a bottom and huts made of hard materials. Special shelters for the pigs exclusively made of bales of straw did not give a significant positive correlation with occurrence of rodents. These results indicate factors that are practicable as preventive measures against rodents. The farmers reported traps, shooting, and cats and dogs as the most frequent non-chemical ways of controlling rodents

Understanding earwig phenology in top fruit orchards

Earwigs, Forficula auricularia, are key generalist predators to a variety of orchard pests. However, numbers of earwigs have declined in both organic and IPM orchards in recent years. Both Integrated and Organic fruit growers have tried to re-establish earwig populations, thus far with little success. To understand earwig population dynamics and to find measures to increase natural orchard populations, we conducted a detailed phenological survey of earwigs in orchards. Earwigs were sampled while sheltering during daytime in artificial refuges. They move into the trees from the third nymph stage onwards. In most orchards, a small second brood is produced in summer, and this has a positive impact on population size in fall. We see only minor differences in phenology between apple and pear orchards, mainly caused by differences in alternative hiding places. Earwigs show an inexplicable reduction in numbers at the timing of moulting into adults. When earwig phenology is correlated with pest phenology in apple and pear, its use for pest control of major pests is clear

Dispersal in Mastomys natalensis mice: use of fine-scale genetic analyses for pest management

Mastomys natalensis is the major pest rodent in sub-Saharan Africa. In this study, population genetic techniques were used to gain new insights into its dispersal behaviour, a critical parameter in pest management. Using 11 microsatellites, 272 individuals from a 300 ha area in Tanzania were genotyped. Genetic diversity was high, with no isolation by distance and little differentiation between field plots far apart, indicating a large effective population size and high dispersal rates in agreement with ecological observations. On the other hand, genetic differentiation between nearby field plots, isolation by distance within a single field plot and kin clustering were also observed. This apparent contradiction may be explained by yearly founder effects of a small number of breeding individuals per square area, which is consistent with the presence of linkage disequilibrium. An alternative, not mutually exclusive explanation is that there are both dispersing and sedentary animals in the population. The low-density field plots were characterized by low relatedness and small genetic distances to other field plots, indicating a high turnover rate and negative density-dependent dispersal. In one field plot female-biased dispersal was observed, which may be related to inbreeding avoidance or female competition for resources. Most juveniles appeared to be local recruits, but they did not seem to stay in their native area for more than two months. Finally, possible implications for pest management are discusse

Ecologically-Based Management of Rodent Pests

Farm Management,

Strategier til giftfri bekæmpelse af rotter og mus

I nærværende delprojekt er første fase en kortlægning, der identificerer de faktorer i systemer med udendørs svineproduktion i Danmark, som kan have betydning for forekomst af potentielle skadedyr og problemer i den forbindelse. Kortlægningen er blevet udført i form af en spørgeskemaundersøgelse. På grundlag af kortlægningen gennemføres efterfølgende en detaljeret beskrivelse af rotters (og eventuelle andre gnaveres) økologi i to udvalgte økologiske svinebedrifter, og der skal udarbejdes strategier til bekæmpelse af gnavere med fokus på rotter. I spørgeskemaet blev der spurgt om forekomst af og problemer med evt. skadedyr blandt pattedyr, fugle og insekter/mider. I denne rapport fokuseres på gnaverne og med hovedvægt på rotterne. Baggrunden for dette er, at der ifølge EU-bestemmelser kun må bruges gift, hvis det kan sikres, at den ikke indgår i fødekæden. Grise kan godt æde rotter og mus. Ifølge dansk lovgivning skal rotter bekæmpes overalt, og i øvrigt er bekæmpelsen et kommunalt anliggende (se Miljøbeskyttelsesloven 2001). Rotter og mus kan overføre smitte (f.eks. Salmonella, Leptospira, Yersinia, Erysipelothrix rhusiopathiae (rødsygebakterien) og Brachyspira hyodysenteria) (Feenstra., et al 2000; Gratz, 1994) til svinene, så alene af den grund kan der være en berettiget grund til at foretage bekæmpelse. Rottebekæmpelse skal udføres af autoriserede personer, mens musebekæmpelse kan udføres af landmanden selv. En stigende bestand af rotter (eller mus) vil utvivlsomt medføre betydelige risici for smitte med ovennævnte sygdomme. Traditionel bekæmpelse med gift er uønsket i økologisk husdyrproduktion. Det er derfor vigtigt, at der udvikles effektive, men giftfrie strategier til bekæmpelse af gnavere i økologisk svineproduktion. Viden om de faktorer, der påvirker niveauet af rotter i økologisk svineproduktion, er meget mangelfuld. I økologisk landbrug er brug af antikoagulanter til rottebekæmpelse tilladt under visse forudsætninger. Uanset hvem der udfører rotte- eller musebekæmpelse, er der en skjult konflikt, så snart der anvendes kemisk bekæmpelse

Gode ideer til giftfri muse- og rottebekæmpelse

I økologisk produktion er det stadig tilladt at anvende antikoagulanter til rottebekæmpelse. Kan brug af kemiske bekæmpelsesmidler i de økologiske bedrifter helt undgås, vil det være i god overensstemmelse med det grundlæggende koncept. Ved avl af frilandsgrise er der yderligere den faktor, at man er meget tættere på den frie natur, så ved brug af kemiske bekæmpelsesmidler har man en potentiel risiko for at påvirke og forgifte ikke-måldyr, altså de dyr der forekommer og ikke optræder som uønskede skadedyr. For at undgå problemer med mus og rotter er de forebyggende foranstaltninger en vigtig forudsætning, og disse skal overvejes både ved etablering og ved den daglige drift. Derved kan den egentlige bekæmpelse begrænses væsentligt

Non-poisonous means for reducing rodent pest problems in organic pig farming

The results indicate factors that are practicable as preventive measures against rodents. Preventive measures are to be considered when planning and laying out the fields for the pigs and when running the farm as well

The Bioeconomics of Controlling an African Rodent Pest Species

The paper treats the economy of controlling an African pest rodent, the multimammate rat, causing major damage in maize production. An ecological population model is presented and used as a basis for the economic analyses carried out at the village level using data from Tanzania. This model incorporates both density-dependent and density-independent (stochastic) factors. Rodents are controlled by applying poison, and the economic benefits depend on the income from maize production minus the costs for maize production, fertiliser and poison. We analyse how the net present value of maize production is affected by various rodent control strategies, by varying the duration and timing of rodenticide application. Our numerical results suggest that, in association with fertiliser, it is economically beneficial to control the rodent population. In general the most rewarding duration of controlling the rodent population is 3-4 months every year, and especially at the end of the dry season/beginning of rainy season. The paper demonstrates that changing from todays practice of symptomatic treatment when heavy rodent damage is noticed to a practice where the calendar is emphasised, may substantially improve the economic conditions for the maize producing farmers. This main conclusion is quite robust and not much affected by changing prices and costs of the maize production.bio-economics; pest control; multimammate rat; crop production

THE USE OF RAINFALL PATTERNS IN PREDICTING POPULATION DENSITIES OF MULTIMAMMATE RATS, \u3ci\u3eMastomys natalensis\u3c/i\u3e

During 3 years we studied a population of multimammate rats, Mastomys natalensis (Smith 1834), in Morogoro, Tanzania. Data were collected in both removal and capture-recapture schemes. We present evidence that patterns of growth and reproduction were related to onset and abundance of rains. This partially explains differences in densities. Additionally, we investigated available literature data and related them with climatological data. A scenario is presented which enables us to predict how densities of multimammate rats may evolve in the following year and whether there will be a risk of outbreaks. The use and implications of this scenario in planning control actions are discussed

Livestock grazing intensity affects abundance of Common shrews (Sorex araneus) in two meadows in Denmark

<p>Abstract</p> <p>Background</p> <p>Current nature conservation in semi-natural grasslands often includes grazing and hay cutting, as well as the abandonment of draining. Semi-natural grassland and in particular meadows constitute important habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews <it>Sorex araneus </it>in relation to livestock grazing intensity in two wet meadows in western Denmark.</p> <p>Results</p> <p>High grazing intensity had a significant negative effect on Common shrew number compared to low grazing intensity and no grazing. Common shrew abundance was generally, but not significantly, higher on the low grazing intensity plots than on the ungrazed controls. No differences in body mass, sex ratio, or reproductive output between Common shrew individuals from the various grazing treatments were found.</p> <p>Conclusion</p> <p>No negative effects of low intensity grazing on Common shrew abundance were found compared to the ungrazed control. Low intensity grazing thus seems a suitable management regime for Common shrews, when grazing is needed as part of the meadow management scheme. High intensity grazing on the other hand is not a suitable management tool.</p