Methods of testing rodenticides in the field against rats

Poisons used in bait to control rats are of two kinds; single-dose acute poisons and those with a slow or cumulative action lethal only if two or more daily doses are consumed. The two types require different baiting techniques and different methods must be used for testing them in the field. For acute poisons, the relative sizes of rat infestations have to be measured by baiting with unpoisoned bait both before and after poison baiting and the pre-treatment sizes taken into account when analysing the results. When testing possible cumulative or multiple-dose poisons, pre-treatment baiting is unnecessary and the method used was that originally devised for field testing for anticoagulant resistance in rats. Examples of published results of field trials of both types of poison are discussed.     

Validating census methods to measure changes in house mouse populations

BACKGROUND: Tracking and census baiting are two techniques that are commonly advocated for monitoring the size of mouse populations. However, currently these techniques are only able to provide an index of population size, rather than an assessment of absolute numbers. In this study the authors tested the reliability of both tracking (footprints left on tiles of fixed size) and census baiting as indices of population size, and sought to calibrate levels of activity and bait consumption under both semi‐natural and field conditions (inside farm buildings). RESULTS: Under semi‐natural conditions, census baiting produced more satisfactory population estimates than those derived from tracking activity. An initial field trial established that the optimum bait point density for this technique was 1 point per 2 m. Subsequent field trials demonstrated that the bait census technique offers a way to estimate the approximate size of stable populations of mice (population size = (mean daily bait consumption ‐ 36.3)/2.46). CONCLUSION: The results to date are sufficiently encouraging to support the use of this cost‐effective approach to monitoring mouse numbers in the type of habitats investigated in this study. © Crown copyright 2008. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.     

Biochemical and histochemical studies on the digestive gland of Eobania vermiculata snails treated with carbamate pesticides

In this study the land snail (Eobania vermiculata), one of the most abundant gastropod of Egyptian farms, was investigated to determine the lethal toxic action of methomyl and methiocarb and to identify the biochemical and histochemical changes as a function of sublethal dose or concentration on the digestive gland of this snail under laboratory conditions, using topical application and baiting techniques. The results showed that methomyl exhibited greater efficacy than did methiocarb against the snails in both techniques. However, higher mortality rates were obtained in the topical application technique than in the poison bait experiments. Biochemical and histochemical examinations revealed that treatment of the snails with methomyl and methiocarb either by topical application or toxic baits caused significant decrease in carbohydrate, lipid and protein contents. This decrease was also more obvious after topical application than after baiting technique, and methomyl was found to be more toxic than methiocarb.     

Evaluation of selective media and bait methods for estimating Phytophthora cactorum in apple orchard soils

Soil plating, with a specially devised selective medium, gave estimates of Phytophthora cactorum in an East Mailing Research Station apple orchard soil up to three times those obtained by dilution and baiting with apple seedlings or cotyledons and using the most probable number analysis.
When the same techniques were applied to a range of soils from apple orchards in south-east England with a history of P. cactorum diseases the plating method failed in most instances, mainly because Pythium spp. rapidly swamped the plates. The dilution/baiting method was applicable to all soils though there was a tendency to underestimate because of anomalous results at lower soil dilutions.
Oospores were the only propagules which could be confirmed as sources of P. cactorum colonies on soil isolation plates.     

水霉属菌(Saprolegnia)分离培养技术研究

 对水霉(Saprolegnia)的分离培养技术进行了探索,筛选出大麻籽、油菜籽、红花籽、苍蝇、蚜虫、小麦粒、玉米片、茶叶、葵花仁9种材料作为诱发水霉菌的诱饵。其中油菜籽能防止腐霉菌(Pythium)污染,是初步纯化菌种、排除杂菌的适宜饵料。同时发现控制温度能使水霉在最短时间内分别产生无性或有性繁殖。在水培条件下,25℃左右适合菌丝及无性器官的发育,有性器官却不能产生,而只有在15~17℃条件下才能使水霉很快进入有性生殖阶段;在加入200mg/L链霉素的CMA培养基上促发有性阶段则需要在25℃左右的温度下进行,方能缩短培养时间。     

Population Dynamics of Biocontrol Agents and Pathogens in Soils and Rhizospheres

Understanding the dynamics between a pathogen and a biocontrol agent (BCA) in soil or in an infection court such as the rhizosphere is crucial for predicting the success of biological control. This is especially true for biological control using the strategy of reduction of initial inoculum prior to infection. By studying the population density fluxes over time, one can observe how the BCA and pathogen influence each other's population and life cycles, and how the biological and physical environment influence this relationship. Methods for quantifying fungi and bacteria in soil, including classical (dilution plating, baiting, bioassays), immunological (ELISA, IFC, immunomagnetic) and molecular (DNA hybridization, PCR, marker and reporter genes) methods, are discussed and critiqued. Finally, the value of mathematical modeling of population dynamics as a means of providing important information about the tripartite relationship between the pathogen, BCA, and host plant is reviewed.     

柑橘大实蝇诱杀方法研究及防治效果初步评估

通过对柑橘大实蝇诱捕器悬挂高度及悬挂方位的效果比较,结果表明,诱捕器在树冠中层悬挂最为合适,与悬挂高度无关;诱捕器在阴面或者平地北面效果最好,阳面最差。诱杀柑橘大实蝇的合适配方为5%橙汁 5%水解蛋白 5%酒或5%红糖液 5%橙汁 5%水解蛋白。在柑橘大实蝇不同防治方法中,结合防治效果、成本及生态影响评估结果表明,诱杀方法最为合适。     

The problem of Pitymys voles in orchards in central and southern Italy1

Voles of the genus Pitymys have in recent years caused serious damage in orchards (apple, citrus) in central and southern Italy. They gnaw the roots and base of the trunk of young and mature trees, killing them in a few days. The outbreaks can be related to certain recent changes in cultural practice, especially the introduction of overhead irrigation. Results are presented for control trials by trapping or by chlorophacinone baiting.     

Termite (order Blattodea,infraorder Isoptera) baiting 20 years after commercial release

Termite baiting is now one of the two main management tools in developed countries after 20 years of commercial release. It has two main goals: to use small amounts of active ingredient and ‘colony elimination’, i.e. death of all individuals in the colony. We consider how well baiting has been evaluated from 100 studies in the scientific literature. Studies have included 15 active ingredients, 23 termite species and 16 countries, yet most studies have focused on the chitin synthesis inhibitor hexaflumuron, Reticulitermes and the United States. Baiting has mostly met its goals: typically about 0.5 g of active ingredient was used, and colony elimination achieved, albeit with rates varying from 0 to 100%, and sometimes supplemented with liquid insecticide. Baiting was most successful using chitin synthesis inhibitors against Reticulitermes and Coptotermes (Rhinotermitidae), in temperate locations, although colony elimination was usually inferred indirectly – mostly by termite absence from baits – and was often slow, from 25 to 450 days. Baiting has been less tested and less successful against higher termites in tropical locations, where they are most diverse and abundant. Future research may have to consider greater termite species diversity and other active ingredients to reduce control times in order to fulfil the potential of baiting. © 2014 Society of Chemical Industry     

Brodifacoum is effective against Norway rats (Rattus norvegicus) in a tyrosine139cysteine focus of anticoagulant resistance in Westphalia,Germany

BACKGROUND: The tyrosine to cysteine amino acid substitution at location 139 of the vkorc1 protein (i.e. tyrosine139cysteine or Y139C) is the most widespread anticoagulant resistance mutation in Norway rats (Rattus norvegicus Berk.) in Europe. Field trials were conducted to determine the incidence of the Y139C mutation at two rat‐infested farms in Westphalia, Germany, and to estimate the practical efficacy against them of applications, using a pulsed baiting treatment regime, of a proprietary bait (Klerat^?) containing 0.005% brodifacoum. RESULTS: DNA analysis for the Y139C mutation showed that resistant rats were prevalent at the two farms, with an incidence of 80.0 and 78.6% respectively. Applications of brodifacoum bait achieved results of 99.2 and 100.0% control at the two farms, when measured by census baiting, although the treatment was somewhat prolonged at one site, possibly owing to the abundance of attractive alternative food. CONCLUSION: The study showed that 0.005% brodifacoum bait is fully effective against Norway rats possessing the Y139C mutation at the Münsterland focus and is likely to be so elsewhere in Europe where this mutation is found. The pulsed baiting regime reduced to relatively low levels the quantity of bait required to control these two substantial resistant Norway rat infestations. Previous studies had shown much larger quantities of bromadiolone and difenacoum baits used in largely ineffective treatments against Y139C resistant rats in the Münsterland. These results should be considered when making decisions about the use of anticoagulants against resistant Norway rats and their potential environmental impacts. Copyright © 2012 Society of Chemical Industry     

Modelling the behaviour of organic chemicals in soil and ground water

The development, testing and application of computer models for the behaviour of organic chemicals, especially pesticides, in soil and ground water has been reviewed. Detailed data are needed on the structure and properties of the soil and ground-water systems, and on the flow of water through these systems. Adsorption and transformation of organic chemicals can be studied in the laboratory and the results introduced into the models. The mathematical techniques most frequently used for the solution of the differential equations are briefly discussed. Some models for the behaviour of pesticides in the root zone have been tested against results of field trials and some interesting deviations between computations and measurements emerged. Techniques for the simulation of the behaviour of organic chemicals in the ground-water zone are also available. However input data for the models are often lacking, as are also results of field studies for testing the models.     

An in-situ baiting bioassay for detecting Phytophthora species in irrigation runoff containment basins

Experiments were conducted in irrigation runoff containment basins to assess the effects of bait species ( Camellia japonica , Ilex crenata or Rhododendron catawbiense ), bait type (whole leaf vs. leaf disc), baiting duration (1, 2, 7 or 14 days), baiting depth and growth media (modified PARP-V8 or PARPH-V8) on the recovery of Phytophthora species. A two-rope, flexible bait-deployment system was compared with a one-rope fixed system for bait stability at designated locations and depths. A total of 907 Phytophthora isolates were subjected to PCR-based single-strand conformation polymorphism (PCR-SSCP) analysis to identify to species level. Seven distinct SSCP patterns representing six morphospecies: P. citricola (Cil I), P. citrophthora (Cip I), P. hydropathica (Hyd), P. insolita (Ins), P. megasperma (Meg I & II) and an unidentified Phytophthora species were identified. Irrespective of culture medium, 7 days of baiting with rhododendron leaves consistently resulted in the recovery of the greatest diversity and populations of Phytophthora species with minimum interference from Pythium species. The flexible bait-deployment system was superior to the fixed system, minimizing the risk of bait loss and dislocation of baiting units and allowing baits to remain at designated depths from the surface under inclement weather.     

A Method for Baiting Corticium rolfsii and of Estimating the Sclerotial Population in Soil

Abstract

The use of tissue blocks of Xanthosoma sagittifolim for baiting Corticium rolfsii from soil is described. The baiting technique has been found efficient for gross estimation of the viable sclerotial content of air-dried soil. The results obtained by this method compare well with those determined by the sieving technique of Rodriguez-Kabana et al.     

华北平原旱作区农田害鼠化学防治技术的优化筛选研究

作者研究了不同投饵方式,不同灭鼠季节和不同杀鼠剂的农田灭鼠效果,并研究了溴代毒鼠磷和磷化锌不同浓度与不同投饵量对农田害鼠的灭杀率,筛选出了农田灭鼠优化技术:封锁带式投饵,0.5%溴代毒鼠磷小麦毒饵每堆投饵2克,全年中灭鼠适期为3—4月份。这套优化灭鼠技术较从前采用的灭鼠技术提高了灭效,而且大幅度降低了灭鼠成本。     

华北平原旱作区农田害鼠化学防治技术的优化筛选研究

作者研究了不同投饵方式,不同灭鼠季节和不同杀鼠剂的农田灭鼠效果,并研究了溴代毒鼠磷和磷化锌不同浓度与不同投饵量对农田害鼠的灭杀率,筛选出了农田灭鼠优化技术:封锁带式投饵,0.5%溴代毒鼠磷小麦毒饵每堆投饵2克,全年中灭鼠适期为3-4月份。这套优化灭鼠技术较从前采用的灭鼠技术提高了灭效,而且大幅度降低了灭鼠成本。     

Controlling yellow jackets with fipronil-based protein baits in urban recreational areas

ABSTRACT

The western yellow jacket, Vespula penyslvanica (Saussare), is a serious seasonal pest of outdoor venues in the western United States. In the spring, queens and low numbers of workers were captured in heptyl-butyrate-baited traps until early July, when the number of foragers dramatically increased. Microsatellite data suggest that 18 colonies were actively foraging within the park in 2012. Foragers from 11 different colonies were collected at one trap site. In 2012 and 2013, sufficient numbers of foragers were not captured until early August when baiting trials were initiated. Baits were prepared with canned chicken mixed with fipronil for a final concentration of 0.025%. In 2012, a single baiting provided >96% reduction of foragers for at least two months. A second baiting late in the season provided >80% reductions. In 2013, one baiting trial resulted in a 74% and a 93% reduction. A bait acceptance study was conducted in 2014 to test a bait consisting of the juices from canned chicken and 0.025% fipronil incorporated into a hydrogel, and provided a much longer lasting bait in the field.     

An investigation of the parameters of anticoagulant treatment efficiency1

The traditional technique of applying anticoagulant rodenticides, as shaped by long experience in the use of low-toxicity, first-generation anticoagulants such as warfarin, aims to maximize treatment efficiency by maximizing the rate of bait consumption by the target rodents. This is done, somewhat laboriously, by laying surplus amounts of bait initially, and maintaining this surplus throughout the treatment by repeatedly replenishing the bait placements. The suggestion that the high toxicity of the second-generation anticoagulants should enable a more efficient baiting system to be designed is examined experimentally in this field study of the control of Rattus norvegicus on British farms. Bait toxicity, infestation size and the incidence of complete takes of bait were found to be independent and highly significant determinants of treatment duration whilst, in comparison, the size and density of bait points and the frequency with which the bait was replenished were found to be relatively unimportant. However, bait size and, more especially, replenishment frequency had detectable secondary effects, apparently through partial relationships with the incidence of complete takes and infestation size. The results indicate, in relation to the control of commensal infestations of R. norvegicus on British farms, that the use of high-toxicity bait formulations and frequent replenishment schedules increase the speed of control, whilst the number and size of bait placements are relatively unimportant; they also suggest that reductions in the frequency of bait replenishment made in order to save labour could be compensated for by increasing the toxicity of the bait and taking other steps to reduce the incidence of complete takes of bait. The results are discussed in relation to the concept of ‘pulsed baiting'.     

A Bayesian approach to the analysis of environmental fate and behaviour data for pesticide registration

With the harmonisation of data requirements for pesticide registration under EC Directive 91/414 there is need for progress on the techniques used to analyse such data and so help make consistent the judgements applied by national regulatory authorities. This paper proposes a Bayesian technique for combining data from environmental fate and behaviour studies of pesticides in soil. The method uses expert knowledge, based on degradation and adsorption data, and logistic regression methods to form a prior probability distribution for the probability that a given compound leaches. Results from lysimeter experiments are used update the prior knowledge. Data for the compounds bentazone and triclopyr are used to illustrate the techniques. The advantages of the methodology and its implications for the pesticide registration procedure are discussed in the light of possible advances using modern Bayesian statistical techniques and mathematical models. © 1998 Society of Chemical Industry     

稻瘿蚊间歇性暴发原因和治理对策探讨

通过多年的系统调查和观察,明确了稻瘿蚊发生具有间歇性、隐蔽性、暴发性、毁灭性和专一性等5个特点,分析了其在大田县间歇大发生有5个方面的因素。防治上提出农业防治可采取“铲”、“避”、“改”等方法,化学防治应选用具有强触杀、强渗透力药剂,采用毒土法施药技术。     

Comparison of serological, culture, and bait methods for detection of Pythium and Phytophthora zoospores in water

Two immunodiagnostic detection assay procedures were compared with two conventional assays for their sensitivity in detecting propagules of Pythium ultimum var. sporangiiferum , Pythium Group F, Phytophthora cactorum and P. cryptogea in dilution series in sterile distilled water. The most sensitive assay for all four species was the zoospore trapping immunoassay (ZTI). Conventional membrane filtration-dilution plating gave similar results to ZTI with the two Phytophthora spp., but was less sensitive in Pythium detection. Immunodiagnostic dipstick assays and conventional bait tests showed similar sensitivities in the dilution series, and were generally about two orders of magnitude less sensitive than ZTI. The four techniques were also compared for their detection efficacy with water samples collected from horticultural nurseries and in in situ tests of infected root zones of Chamaecyparis , tomato and Chrysanthemum . In these comparisons, ZTI was again the most sensitive test for water samples, although membrane filtration-dilution plating proved to be a more consistent test. Dipstick and baiting assays were the best techniques for in situ testing, and dipsticks provided epidemiologically valuable, quantitative data on pathogen propagule numbers.