Laboratory testing of wood mouse and common vole sensitivity to bromadiolone,sodium selenite,and cellulose

Maintaining the numbers of wood mice and common voles at an acceptable economic level, especially during years of massive outbreaks, is a major challenge in plant protection. Efforts to reduce the negative effects of rodenticides on the environment, to improve the integrated pest control system, and to minimize risks for human and animal health require investigation of the potentials of cellulose, as a natural product, and sodium selenite as rodenticides. The present study was conducted to determine the sensitivity of these rodent species to bromadiolone (a.i. 0.005 %), sodium selenite (a.i. 0.1 and 0.05 %), and cellulose (a.i. 45 %) baits. All experiments were done using no-choice and choice feeding trials. A low acceptance of cellulose baits was found in the choice feeding trial, and the time of first deaths indicate that stress and hunger increase the death rate in both species. The taste had a negative impact on the acceptability of baits containing sodium selenite. Low bait acceptance of cellulose and sodium selenite resulted in lower mortality of both species. The acquired results indicate that bromadiolone remains a more effective solution than cellulose and sodium selenite for control of wood mice and common voles.     

Verdeckte Ausbringung von Rodentiziden in Köderstationen zur Abwehr von Mäuseschäden in Forstkulturen

The Common Vole (Microtus agrestis) and the Redbacked Vole (Clethrionomys glareolus) can cause severe damages in forest plantations. Different application techniques of rodenticides to control these harmful rodents were tested by several institutions of plant protection in the Federal Republic of Germany. The following registered baits were used: A bluestained pectin-wax pellet containing 0.0075% Chlorphacinon (Lepit^®-Forstpellet), small flour-plates (Arrex^®-M-Köder klein) and sunflower kernels coated with plastique-foil (Arrex^®-E-Köder) both incorporated with 2% resp. 3.75% zinc-phosphide. In 1985 disperse spraying versus concentrated offering of the baits in 12 earthenware pipes/ha was tested. The density of mice and voles could be reduced nearly to the same level with both methods. However, the amount of baits needed was much less when bait stations were used. In 1986 a new and save type of bait station (Theyson-Köder-station) was tested, from which non-target animals cannot get baits. The acceptance of the bait station could be improved by aromatic compounds from apples. According to the obtained first results forest plantations can be protected during the whole wintertime against vole-damages by means of bait stations.     

Bekämpfungsversuche gegen die KleinwühlmäuseMicrotus lusitanicus (Gerbe) undM. duodecimcostatus (Sel.-Long.) in Obstkulturen

Tests with different rodenticides against the Iberian Vole (Microtus lusitanicus) and the Mediterranean Vole (M. duodecimcostatus) were carried out in highly infested orchards in Portugal. Best results were obtained with baits containing 0.005% Bromadiolon. Broken carob was a suitable bait material. Apple slices and granulats of lab chow were also accepted, but were destructed very fast by fungi. Cultivation techniques had a great influence on the results. The density of Iberian Voles could be diminished drastically with a combined method of removing the ground cover and subsequent application of poisoned baits. Blowing anticoagulant dusts directly into the galleries of the voles was not very successful until now.     

Über die Wirksamkeit verschiedener Antikoagulantien gegen forstschädliche Wühlmäuse

The susceptibility of rodents in forest cultivations against some anticoagulants was tested in a pilot study. The species used were the Common Vole (Microtus agrestis), the Redbacked Vole (Clethrionomys glareolus) and the Yellownecked Field Mouse (Apodemus flavicollis). The following anticoagulants were administered orally: Coumatetralyl (Racumin^®), Warfarin + Pindon (Actosin P^®), Chlorphacinon + Sulfaquinoxalin (Lepit^®), Bromadiolon, Brodifacoum and Flocoumaphen. Prothrombin times and mortality were observed. Promising preliminary results were obtained with Flocoumaphen which was effective against the harmful voles but not against the useful mice in the plantations.     

Optical and litter collection methods for measuring leaf area index in an old-growth temperate forest in northeastern China

Hemispherical photographs combined with litter collection were applied to determine seasonal dynamics of leaf area index (LAI) between the period of maximum leaf area and the leafless period from an old-growth temperate forest in the Xiaoxing’an Mountains, northeastern China. Our objective is to explore the change in the relationship between “true” LAI and effective LAI (calculated only from hemispherical photography) and to find the best LAI estimation models. Effective LAI in November is corrected for contribution of woody material and clumping at shoot and beyond shoot levels, to give minimum “true” LAI. The “true” LAI in each period is estimated as a sum of the minimum “true” LAI and litter collection LAI in each period. Power function regression calibration models were then carried out between “true” LAI and effective LAI in each period and the entire litter-fall period. Then, significance tests were applied to detect the differences among different models. The results showed that the average “true” LAI ranged from 2.74 ± 0.54 on November 1 to 6.64 ± 1.34 on July 1. For the entire season, average effective LAI was 53.16 % lower than the average “true” LAI. After significance tests, calibration models were classified into two types: (1) maximum LAI period and the period of maximum leaf fall; (2) the period during which leaves began falling and all deciduous leaves had fallen. Based on our experience, we believe that the classified models can produce reliable and accurate LA1 values for the needle and broad-leaved mixed forest stands under the non-destructive condition.     

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

Vole (Cricetidae) girdling of tree trunks is a common form of damage experienced by tree and vine growers throughout much of the Northern Hemisphere. Management programs that effectively incorporate chemical repellents and vegetation management would be of substantial assistance to growers that experience such damage. Anthraquinone has proven effective as a repellent against voles in lab trials, yet controlled field tests of combined anthraquinone and vegetation management programs are lacking. Therefore, we established a mesocosm-based study in central California, USA, to test the efficacy of anthraquinone and vegetation management for reducing girdling damage caused by California voles Microtus californicus to Clementine citrus trees Citrus clementine under semi-field conditions. We observed a 90–100% reduction in girdling damage for trees following a single application of anthraquinone during two trials in summer and spring, respectively. Removal of vegetation around the base of trees further reduced damage during the summer sampling period, with no girdling observed on anthraquinone-treated trees that were surrounded by bare soil. We did not observe this same relationship during spring, and we observed no relationship between vegetation management in the absence of anthraquinone treatments in either seasonal trial, suggesting that vegetation management had a lesser impact on vole girdling than anthraquinone applications. We observed no decrease in efficacy of anthraquinone across the duration of both sampling periods (5–6 weeks), indicating substantial longevity for anthraquinone. Anthraquinone appears to have substantial utility for minimizing vole girdling damage. Field testing is warranted for additional mammalian species to determine potential uses for other taxa.     

Verification of a phenotypic discrimination method for hybrid larch seedlings using DNA markers

The hybrid between Kuril larch (Larix gmelinii var. japonica) and Japanese larch (L. kaempferi) is an important afforestation tree species in Hokkaido, Japan, because of its rapid juvenile growth, straight stem, and resistance to bark gnawing by voles. To produce desirable hybrid seedlings, precise seedling discrimination is essential. However, continuous variations in morphological and phenological traits occur across L. gmelinii var. japonica × L. kaempferi and L. gmelinii var. japonica × L. gmelinii var. japonica seedlings. Therefore, we used DNA markers to verify and improve the morphological and phenological discrimination method. We collected seeds from an interspecific seed orchard and, using chloroplast DNA analysis, we showed that the hybridization rates of 1-year-old seedlings were different between years (2004, 23.2 %; 2005, 53.6 %) and between mother trees (2004, 5.8–39.4 %; 2005, 20.0–81.0 %). Discriminant analyses revealed that the root collar diameter of 2-year-old seedlings, number of sylleptic branches of 2-year-old seedlings, and day of terminal bud set in 1- and 2-year-old seedlings are traits that aid in discriminating hybrid seedlings. The proportions of correctly discriminated individuals were found to be 81.7–88.2 % when using improved phenotypic discrimination methods. These methods adopted traits with high discrimination abilities during discriminant analyses and determined the selection intensity according to the hybridization rate estimated from the DNA markers. In contrast, the proportions of correctly discriminated individuals obtained using the current method were lower, 72.7–78.5 %, because this method was based on seedling height and adopted a constant selection intensity.     

Studies on the suitability of trap-tubs to control noxious rodents in forests

Various types of trap-tubs were tested both under controlled conditions in standardised trial series and in the field. New trap-tubs were poorly accepted by the animals, whereas weathered tubs were readily accepted within a very short period of time. The trapping mechanisms of tubs used in Lower Saxony and improved tubs in Hesse were both found to be suitable. The trapping method proved to be highly selective since long-tailed mice (Apodemus spp.) can easily escape by jumping onto the edge of the tub. Voles (Microtus agrestis, Clethrionomys glareolus) explored the inside of the tub and worked its exits with decreasing intensity during the time of captivity. They died of hypothermia within a few hours. Elimination of the trapped rodents by their natural enemies was not observed. The trials showed that trap-tubs are suitable for selective reduction of the density of field voles and red-backed voles in forests. The results also contribute to assessing the humaneness of the control method.     

艾虎气味对根田鼠行为和繁殖的影响(英文)

本文主要利用艾虎（Mustila eversmanni）气味作为捕食风险源，于1997年4月至12月在中国科学院西北高原生物研究所生态学实验室，研究其对根田鼠（Microtus oeconomus）社会行为、觅食、繁殖和性激素的影响。结果表明，当暴露于艾虎气味中时，根田鼠产生繁殖迟滞，且交配行为的频率显著降低(P<0.01)。与对照组相比较，雌体亲密行为和两性一般动作的累积时间显著增加（P<0.01）。两性一般动作（P<0.01）、探究活动（雌体：P<0.05；雄体：P <0.01）和自我修饰（P <0.01）的频次显著降低。同时，根田鼠能量的摄入（P<0.05）和体重（P<0.01）都显著降低。雌体的卵巢指数和胎仔重量也显著降低（P<0.01），雄体的附睾精子数则极显著降低（P<0.01）。艾虎气味条件下，根田鼠雌体的血清孕酮显著增加（P<0.01）。     

Targeting hidden pests: acaricides against the coconut mite <Emphasis Type="Italic">Aceria guerreronis</Emphasis>

The control of hidden pest species with pesticides depends on the accurate timing of the application to reach the life stages during their only moment of vulnerability, which is when the pests (temporarily) leave their hiding places. A curious case involves the colonization of the coconut perianth, a bract-protected region of the fruit, by the coconut mite Aceria guerreronis. The coconut bracts apparently provide protection against the direct action of acaricides used against the coconut mite. Furthermore, some acaricides target mite eggs and/or immatures in addition to adults, leading to enhanced mortality and/or compromised progeny production, but only if reaching these stages. In this study, we developed methods for assessing the likely protection provided by the coconut bract against the acaricides used for managing the coconut mite. We also assessed the efficacy of the acaricides currently registered for use against this species. Our results support the notion that coconut bracts provide protection to the coconut mite against direct acaricide action. Some acaricides (abamectin and fenpyroximate) were effective only with the removal of the coconut bracts, whereas others (hexythiazox and spirodiclofen) were not effective even with bract removal. Coconut mites sheltered by bracts were protected against the acaricides over time, but the acaricides seemed to induce mite dispersion. In addition, the preventive application of some acaricides reduced the chances of the perianth colonization by the coconut mite. Among the acaricides used, two (hexythiazox and spirodiclofen) are registered as ovicides, but only one (spirodiclofen) acted on eggs, preventing hatching of approximately 40 % of the eggs. The acaricide impacts on coconut mite management are discussed.     

Impacts of fiber orientation and milling on observed crystallinity in jack pine

Influences of fiber orientation and milling on wood cellulose crystallinity were studied using jack pine wood. The fiber orientation effects were measured by sampling rectangular wood blocks in radial, tangential, and cross-sectional orientations. The influence of milling was studied by analyzing the unsieved and sieved milled wood fractions (all <1,000 μm). Fiber orientation effect was manifested in both X-ray and Raman measurements and was dependent upon the orientation of the sampled wood blocks. In Raman, the observed crystallinity was similar between the blocks sampled on the tangential and the radial faces. However, the estimated values were 5.5 % lower compared to that measured in a powdered sample pellet. Moreover, in these sampling modes, the orientation of the block with respect to the direction of the electric vector of the laser made a difference only for the tangential mode of sampling. When a wood block was sampled on the cross-sectional face, the observed Raman crystallinity was 3.9 % higher from that of the pellet. The observed crystallinity did not significantly differ with change in sample orientation with respect to the electric vector direction. In contrast, the Segal-WAXS study of the blocks indicated that compared to the pellet, the estimated crystallinities in the radial, tangential, and cross-sectional sampling modes were 5, 2, and 11 % lower, respectively. This suggested that the radial and the tangential faces of the blocks can be used to estimate the crystallinity of wood. With regard to the effect of milling on Raman and Segal-WAXS estimates, the wood crystallinity did not depend upon the particle sizes of the fractionated samples and was similar to that of the original unfractionated ground wood.     

Empfindlichkeit von Hausmäusen verschiedener Herkunft gegen Antikoagulantien

Various subspecies ofMus musculus and related species are worldwide in distribution. In the temperate regions this rodent lives in the field throughout the year. it can cause severe damages to various crops, i. e. in Egypt the new reclaimed areas within the desert are heavily infested, and in Portugal seeds in greenhouses are often destroyed.The control of the house mouse is increasingly difficult because this pest rodent has become resistant to many rodenticides in some regions. The house mouse also inspects and is cautious when selecting its food, especially poisoned baits, and develops bait-shyness rapidly.The efficacy of several anticoagulants against house mice of different origins was tested. The animals were caught in the surrounding areas of Munich, Lisbon, and Cairo. An albino laboratory strain served as a standard. The rodenticides were diluted with olive oil and administered in varying doses to the animals. Before and after treatment the mortality and the prothrombin times of the test animals were observed. The following anticoagulants are ordered according to their increasing efficiency: Coumarin, Coumatetralyl, Chlorphacinon + Sulfachinoxalin, Difenacoum, Bromadiolon, and Fluocoumaphen.The susceptibility of different subspecies of the house mouse to the anticoagulants varied remarkably.M. m. spretus from Portugal was very resistant to all the tested rodenticides whereasM. m. praetextus in Egypt was highly susceptible.In Egypt bait preference tests and some experiments with ready made baits containing Difenacoum (RS 2®), Chlorphacinone + Sulfachinoxalin (Raviac®), and Warfarin (Coumafene®) were conducted in the field. Wheat was the preferred bait as compared to sunflower kernels, maize, and chicken pellets. The acceptance was slightly improved by adding a small quantity (5–15%) if sesame to the bait but not in combination with oliveoil, maizeoil or cottonoil. In small testplots in 0,5 ha of straw heaps and in 1 ha of maize fields the bait consumed was reduced on the seventh day by more than 70% after application of anticoagulants, but increased very rapidly when the treatment was interrupted because of reinfestation.

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Mit 4 Tabellen     

Evaluation of the effectiveness ofBacillus thuringiensis var.entomocidus as a pest control agent to replace chemical pesticides in alfalfa fields in Israel

The Egyptian cotton leafworm,Spodoptera littoralis Boisd., is the main important pest of alfalfa in Israel. Population levels of other pests usually do not reach the economic threshold. Nine chemical insecticide applications (7 spray applications and 2 granular fluorosilicate baits) were required to controlS. littoralis during the season of 1984 (in which infestation level was high) whereas only 5 applications of aBacillus thuringiensis var.entomocidus (Bte) preparation (3 sprays and 2 baits) produced the same effect. During 1983 and 1985 pest populations were moderate and only 6 chemical pesticide applications were required. A bait ofBte on wheat bran, Coax^®, developed in the present study was effective in the control of large larvae (instars 4–6). Hay yields of fields treated withBte were similar to the yields of a conventionally treated field. The best control of large larvae was obtained by applying the bait preparation under the wind row during the alfalfa cutting.     

Comparative microsporogenesis and flower development in <Emphasis Type="Italic">Eucalyptus urophylla</Emphasis> × <Emphasis Type="Italic">E. grandis</Emphasis>

Microsporogenesis and flower development in Eucalyptus urophylla × E. grandis were examined using chromosome tableting to provide a method to predict the meiotic stages in this species. Although microsporogenesis was normal, cytokinesis during meiosis of pollen mother cells occurred simultaneously, with strong asynchronism observed in the two different lengths of stamens in a flower bud. In a single flower, the developmental period of microsporogenesis in anthers on the longer stamens was always ahead of those on the shorter stamens. Flower development was also asynchronous at different locations on a branch. Flower buds on the upper side of the branch were larger in diameter than those on the lower side. In addition, a correlation was observed between microsporogenesis development and flower bud diameter growth. The pachytene stage was first observed when the diameter of the flower buds increased to 3.0 mm, and the majority of the meiotic stages were observed when bud diameters ranged from 3.5 to 5.0 mm. This study showed that the developmental stages of microsporogenesis in Eucalyptus urophylla × E. grandis could be distinguished readily, which may be applicable to future breeding studies.     

樟子松幼林地投放袋装毒饵灭鼠试验初报

森林害鼠尤喜啃食樟子松幼树地际的树皮,致其养分与水分运输阻断而死亡。利用袋装毒饵和散投毒饵在樟子松人工林地进行灭鼠试验,结果表明:袋装毒饵不影响害鼠咬食,灭鼠效果优于散投毒饵;袋装毒饵比散投毒饵的残效期延长达5个多月,两者差异显著。投放袋装毒饵是一种安全、有效的灭鼠方法。     

Consumption of Bark and Seeds by Voles in Relation to Habitat and Landscape Structure

Voles cause damage in forestry by eating the bark of seedlings and the seeds of conifers. Folivorous field voles ( Microtus agrestis ), restricted to various types of grassland, are mainly responsible for damage to bark, and granivorous bank voles ( Clethrionomys glareolus ), supported by most forest environments, for the consumption of seeds. Densities of bank and field voles, consumption of bark on indigenous and experimental woody plants, and consumption of experimentally supplied seeds were measured during the vole cycle 1997-2000 in relation to three habitat and three landscape variables. Landscape variables explained field vole densities and consumption of bark to a considerable extent, while habitat variables were more adequate for densities of bank vole and consumption of seeds. Field vole populations may demonstrate a ''mass effect'', where the success of early development and dispersal from subpopulations will decide peak numbers over entire landscapes. Numbers of field voles may affect numbers of the inferior bank vole. Thus, predicting the exact location of vole damage is principally difficult.     

Weed dynamics during the change of a degraded pasture to agroforestry system

This study evaluates weed dynamics during the first 4 years (2008–2011) of the implementation of an agroforestry system in the municipality of Tomé-açu in the state of Pará, Brazil. The study was conducted in a degraded pasture of Brachiaria humidicola, and treatments (T) included mixed plantations of oil palm with short-cycle leguminous species (T1) with the inclusion of manioc in T2 and forest species and palm trees in T3. In 2008, a floristic survey was conducted in 12 plots of 2 × 2 m per treatment. In 2009, herbicide was applied to one half of the area in each treatment. A total of 19,367 individuals of height <1.5 m were surveyed, of which 51 % were B. humidicola and 21 % were leguminous species that had been planted. Overall, an increase in plant density was observed between 2009 and 2010, followed by a decrease over the following year in areas without herbicide and a tendency for high densities to persist in areas with herbicide. Species richness increased over the study period in all areas (with or without herbicide), which might be related to habitat availability resulting from the reduced density of B. humidicola due to the effects of the herbicide, the leguminous species planted and the development of the agroforestry system. The association of short-cycle leguminous plants with afforestation appears to be an effective method for controlling weeds in the absence of herbicides.     

Köderscheu bei Wühlmäusen (Microtinae)

Zusammmenfassung Im Rahmen der amtlich vorgeschriebenen Prüfung von Rodentiziden wurde beobachtet, daß Jungtiere der Rötelmaus und der Erdmaus, die noch im Familienverband mit ihren Eltern leben, besonders häufig köderscheu werden. Offensichtlich ermöglicht das Lernverhalten der Jungtiere bei der Nahrungsaufnahme der Eltern ein allmähliches Kennenlernen geeigneter oder ungeeigneter Nahrung. Die Jungtiere nehmen häufig feine Nahrungspartikel von den Lippen, insbesondere des Muttertieres auf. Somit können sie allmählich auch Erfahrungen über die Wirkung von akut wirksamen Rodentiziden sammeln, ohne selbst eine letale Dosis aufzunehmen. Hinweise über eine weitergehende Informationsübertragung, die zur Köderscheu führen kann, wurden nicht gefunden.

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Bait shyness of voles

Some rodents like the Common Vole (Microtus agrestis) and the Bank Vole (Clethrionomys glareolus) can cause severe damages in forest cultivations and orchards by gnawing roots and bark of the trees. Among other countermeasures zinc phosphide baits are used to prevent losses. However, some individuals get bait shy against the used acute poison usually. It was observed in some choice tests that young voles can learn very easily from her parents to avoid baits which contain an acute poison. The nestlings are licking the lips especially of her mother during food consumption. In this way they can get some information about palatable and non-palatable food items. Young voles living in her family can become bait shy rapidly during the learning and food imprinting process.

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Mit einer Tabelle     

Long-term development of soil organic carbon and nitrogen stocks after shelterwood- and clear-cutting in a mountain forest in the Bavarian Limestone Alps

Forest soils store large stocks of soil organic matter (SOM) and are of vital importance for the ecosystem supply with nutrients and water. According to the available literature, depending on management regime and site properties, different negative and positive effects of forest management (particularly of forest thinnings and shelterwood cuttings) on soil organic carbon (SOC) and nitrogen (N) stocks are observed. To elucidate the long-term impact of different shelterwood systems and small clear-cuttings on the OC and N stocks of shallow calcareous soils in the Bavarian Alps, we conducted soil humus inventories on different plots of a mixed mountain forest management experiment started in 1976. The silvicultural multi-treatment experiment consists of a NW-exposed Main Experiment (ME) site with eight plots of different cutting intensity (two unthinned controls, two light shelterwood cuttings = 30 % of basal tree area removed, two heavy shelterwood cuttings = 50 % removed, and two clear-cuttings = 100 % removed) on Triassic dolostone. Additionally, plots were installed at a N-exposed dolostone (ND) site and two sites (FL, FH) on Flysch sandstone (each with one unthinned control and one heavy shelterwood cutting). The shelterwood cuttings from 1976 were repeated in 2003 to re-establish the overstorey basal area as produced by the first cutting in the different plots. Thirty-five years after the first treatments, forest floor SOC and N stocks were significantly decreased (up to ?70 %) at the different shelterwood and clear-cut treatments compared to the unthinned control at the ME site despite vigorous development of natural rejuvenation. Also significantly smaller topsoil (forest floor plus mineral soil 0–10 cm depth) OC stocks (between ?16 and ?20 %) were detected at the thinned compared to the control plots. Differences in topsoil N stocks were also considerable (between ?3 and ?14 %), but substantially smaller than OC stock changes. For the total soil down to 30 cm depth, OC stocks in the differently thinned plots were consistently smaller compared to the unthinned control plots. Comparable to our findings at the ME site, heavy shelterwood plots at the three other sites (ND, FL, and FH) showed significant losses of OC in the forest floor (up to 43 %), mineral soil (up to 38 %), topsoil (up to 38 %), and total soil (up to 34 %). Significant large absolute and relative SOC decreases coincided with sites characterized by large initial humus stocks. Moreover, significant effects of heavy shelterwood cuttings on SOC and N stocks (on average 23 % SOC loss and 13 % soil N loss for the forest floor plus the uppermost 10 cm mineral soil) were detected on a regional level. Our results show that different shelterwood systems are accompanied with a considerable long-term decrease in OC and N stocks in shallow calcareous forest soils of the Bavarian Alps. However, a comparison with a windthrown forest stand at a nearby similar site indicates that SOM losses after thinning operations are small compared to decreases following windthrow or other calamities with subsequent large soil erosion and increased mineralization processes.     

广适性有机栽培基质筛选试验研究

利用菇渣、畜禽粪、枯枝落叶等农林废弃物为主要原料研制有机环保型栽培基质,既可以减少农业面源污染,变废为宝,又可节省土壤、草炭等难再生资源。经3批田间栽培试验表明:以菌苞为主要原料发酵的基质处理均效果良好,而以枯枝落叶发酵的基质处理均出现异常,表现不及对照。3批栽培试验中综合表现最好的基质配方为处理1:菌苞60%+畜禽粪30%+草炭10%+发酵菌1。