Cholecalciferol plus diphacinone baits for vole control: a novel approach to a historic problem

Combination baits containing cholecalciferol plus an anticoagulant are effective against commensal rodents resistant to anticoagulants, and they likely pose less risk than anticoagulant-only rodenticides due to lower concentrations of active ingredients and shorter time to death. However, these combination baits have not been tested for agricultural rodent pests. Therefore, we established a study to test the efficacy of cholecalciferol plus diphacinone artichoke bract and pellet baits to determine their ability to manage California voles Microtus californicus in artichokes, where resistance to anticoagulants is known to occur. Field tests using radiocollared voles indicated that bract baits were highly efficacious (85 %), although pellet baits were less effective (60 %). Low observed efficacy of pellet baits may have resulted from poor weather following application during the second sampling period; further testing may yield more positive results. We observed a bimodal distribution in timing of death, with one group of voles dying between 4.3 and 5.8 days post-consumption; the other group died between 9.0 and 14.5 days post-consumption. Deaths in the first group were attributed to cholecalciferol, while deaths in the second group were likely due to chronic anticoagulant exposure. Almost double the proportion of voles that died from bract consumption did so during the early period when compared to their pellet plot counterparts. This suggests that voles were consuming greater quantities of bract baits over a shorter period of time when compared to the pellet bait. Collectively, these findings indicate that baiting with cholecalciferol plus diphacinone coated bracts is an effective method for controlling vole populations in artichokes.     

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.     

Studies on food selection behaviour of the Norway rat (Rattus norvegicus) on farms

Measures used to control Norway rats (Rattus norvegicus Berk.) on farms are frequently unsuccessful due to poor bait uptake. In pest-control operations, rats always have the choice between the farms own food resources and the bait. In this study we analysed the individual selection behaviour in two rat colonies when the rats were offered a familiar bait which matched the food on the farm and a bait which was unknown. Bait stations equipped with video and transponder technology were installed in two differently structured areas on a farm. In four experiments, a familiar foodstuff (rolled oats) was put out for 3 days, and then at one of the stations, a test bait was put out for 4 days. The relative palatability of the test baits was known from laboratory experiments. The visits of marked individuals were registered, and the amounts consumed were estimated in the video evaluation. Location preference was determined by offering identical food in two neighbouring bait stations. Social interaction was evaluated using the video recordings. The bait stations were visited on a daily basis irrespective of the supply. Food selection patterns (and bait acceptance) observed in the two differently structured areas on the farm were different. However, the relative palatability among the four test baits was stable and agreed with the ranking in laboratory experiments. Over the days of the experiment there was no significant difference in bait acceptance. Location preference and social interaction influenced the choice of bait station. The results show that it is possible to predict bait palatability in the laboratory, which is an important prerequisite for good bait uptake. However, the bait acceptance level is ultimately determined by the prevailing living conditions in the respective area. For optimising bait uptake, the structure of the areas on the farm must be considered just as much as findings about location preferences and social interaction.     

Erfahrungen mit verschiedenen Ködermitteln und unterschiedlicher Ausbringungstechnik zur Bekämpfung forstschädlicher Wühlmäuse

On 17 field plots of 0,25 to 1 ha in forest plantations of southern Germany various commercial baits containing zinc phosphide, chlorphacinon and diphenacoum were tested in a pilot study for control of harmful small rodents likeMicrotus agrestis, M. arvalis andClethrionomys glareolus. The baits were dispersed in different concentrations over the ground or alternatively they were put together with a piece of apple in bait stations. The animals in the field plots were trapped by means of live traps, marked and released. The efficacy of the treatments was tested by repeating this procedure in consecutive time intervals and by analysing the fractions of marked and unmarked specimens. In comparision with a disperse distribution of the unprotected baits over the ground surface better results and a more lasting success could be mostly obtained with only 9 earthenware pipes distributed over one hectare and filled with a small amount of baits together with a piece of apple. The advantages and disadvantages of the bait station technique are discussed. It is assumed that the efficiency of the bait station technique can be improved by means of attractants and pheromones.     

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     

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     

Effect of synthetic hormones on reproduction in <Emphasis Type="Italic">Mastomys natalensis</Emphasis>

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.     

The result of bagged Pyrinuron baits for controlrodent pest of forests

Introduction' CI6thrionomus rutilus and C. rufocanus were majorforest rodent pests in Northeast China (Yang 1997).As the area of artificial forestS has been increasinglyenlarged, the occurrence of rodent pests also has anincreasing t6ndency in Heilongjiang Province (Hou1995). The plantstions of LaFiX gmelipi and PioussylvestFiS var mongoliCS suffer from rodent peStsmore seriously, even affected forestry produCtion.Pyrinuron, a kind of rot6nticide which was formulatedby authors' self, w…     

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.     

Mäuseschäden in Forstkulturen

Some rodent species of the family Arvicolidae especially the Field Vole (Microtus agrestis), the Bank Vole (Clethrionomys glareolus) and the Water Vole (Arvicola terrestris) can cause severe damage in broadleaved and mixed forest cultivations. Up to now the losses can be diminished only by reduction of vole density during wintertime. The use of rodenticides in the cold season did not affect the development of rodents during summertime. Risks of primary and secondary poisoning can be avoided using special bait stations and environmental save agents.     

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。     

黑翅土白蚁的食物选择性研究

通过观察黑翅土白蚁的觅食行为,对黑翅土白蚁的食物选择性作了研究。室内结果表明:在6种纯饵料中,小米粉的被食率、泥被面积及泥被覆盖率均最高,其泥被出现时间仅长于松木粉,但两者间无显著差异。在5种添加物中,除15%黑木耳外,15%香菇、10%松花粉、10%白砂糖、15%蜂蜜都能显著提高小米粉对黑翅土白蚁的诱食效果,其中又以10%白砂糖的增效作用最为明显。野外试验结果表明,小米粉 10%白砂糖诱饵对黑翅土白蚁的诱食效果优于小米粉诱饵。可见,小米粉 10%白砂糖是最优化的饵料组合,可作为黑翅土白蚁毒饵中的饵料组分。     

中华鼢鼠防治技术研究

通过4种药剂毒饵防治的对比研究和人工地箭防治,结果表明,溴敌隆毒饵不仅防治效果较好(86.7%),且属第二代抗凝血杀鼠剂,对其他动物低毒,不产生二次中毒现象;人工地箭的防治效果为62.7%~81.3%,平均74%,都是目前防治中华鼢鼠的较佳方法。     

Field tests on the efficacy of baits based onBacillus thuringiensis and chemical insecticides against the greasy cutwormAgrotis ypsilon Rdf. in Egypt

Field tests were conducted to determine the effectiveness of wheat-brain baits based onBacillus thuringiensis var.kurstaki HD-1 (dipel 2x) compared to the organophosphorous insecticide Hostathion against the greasy cutwormAgrotis ypsilon infestations on horse bean (Vicia fabae) cultivations. Significant larval reductions were observed in all treated plots after one application with a significant increase in the yield (1.45–1.60 folds) compared to the control plots. The yield was not obviously affected by varying the dose of dipel in the bait between 150–250 g/feddan. The addition of the adjuvant potassium carbonate to the dipel bait caused a significant larval reduction, 10 days after application and showed to be as efficient as baits based on Hostathion.     

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.     

长白山不同生境红松种子消耗率与鼠类数量关系的研究

在红松阔叶林和白桦次生林两种生境中人工模拟松鼠埋藏红松种子,研究种子消失率与鼠类及其密度的关系,结果表明:鼠类在10日内对人为埋藏红松种子的平均消耗率为74.7%±6.9%,红松阔叶林为92.5%±3.9%,白桦次生林为57%±10.9%,差异显著(t=-2.986,P<0.01);而种子消失率与啮齿类数量呈正相关(R2=0.742,P<0.01)。白桦次生林红松更新幼树为75～130株.hm-2,显著大于红松阔叶林的6～15株.hm-2,与鼠类消耗种子速度有一定关系。     

白蚁诱饵剂成型工艺的研究

我国在 2 0世纪 70年代后期开始研制毒饵来诱杀白蚁 ,同时对毒饵的型式也进行了一定的研究 (江西永修县林业科学研究所 ,1979)。 1985年 ,原中国白蚁防治科技协作中心 ,协调、组织地方各级白蚁防治研究所共同研制出了银耳真菌腐木屑胶冻剂、蜂粉膏剂、纸袋粉剂和纸块 (管 )剂 (黄远达 ,2 0 0 1)。林树青 (1993)在研制中草药诱饵剂的过程中 ,进行了诱饵剂包装材料的筛选 ,并把中草药诱饵剂制成了诱饵包。罗均泽等(1988)、何复梅等 (1997)和佘春仁等 (1999)利用白蚁踪迹信息素及其类似物与灭蚁灵等药剂混合分别制成了诱杀包、诱杀块等型诱饵。…     

Versuche zur Wirkung von Calciferolködern gegen Ratten und Mäuse in Ägypten

Experiments with 0.1% Calciferolbait (product of DETIA FREYBERG GMBH, Fed. Rep. of Germany) for combatting rats and mice were conducted in the laboratory, stores, and in the fields in Egypt. Efficacy of Calciferolbait on sunflower seeds as well as on wheat-kernels was tested in laboratory experiments against various rodent species spreaded all over the country. In general it was observed, that the quantity consumed by the test animals was higher for maize alone without toxicant than that for Calciferolbait. Results obtained by practical use of Calciferolbait on sun-flower seeds as well as on wheat in the stores and the field revealed that both baits were effective against rats and mice; but the attractivity of sunflowerbait was in general slightly higher than that of wheatbait. In other trials the efficacy of a further Calciferol-freshbait plus 3% sunflower oil as well as of a Calciferol-freshbait without addition of sunflower oil was examined. Results showed that both Calciferolbaits were effective, but the attractivity of the bait with addition of 3% sunflower oil was better than that of the bait without sunflower oil.     

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.     

Integrierte Bekämpfung forstschädlicher Wühlmäuse

Mainly the following four species of voles (Arvicolidae) are harmful in forest plantations in Central Europe: the field vole (Microtus agrestis), the common vole (M. arvalis), the redbacked vole (Clethrionomys glareolus) and the water vole (Arvicola terrestris). Different possibilities of development of an integrated control programme are discussed. The most important factors are: identification and forecasting of damages, determination of control thresholds, optimized timing of control operation and selection of efficient control methods with minimized environmental hazards. Finally the system of surveillance of rodents in Bavarian forest plantations is described, whereby different preventive measures by means of forest cultivation play an important role. Furthermore new methods of forecast and of control such as bait station technique with new types of rodenticides and attractants are tested.