Resistance of cabbage (Brassica oleracea capitata group) crops to Mamestra brassicae

Twenty-one cabbage (Brassica oleracea capitata group) varieties, including 16 local varieties and five commercial hybrids, were screened for resistance to the moth Mamestra brassicae L. under natural and artificial conditions in northwestern Spain. Resistance was assessed as the proportion of damaged plants and damaged leaves, leaf feeding injury, and number of larvae present. Correlation coefficients among damage traits showed that a visual scale (general appearance rating) should be a useful indicator of resistance. Most local varieties were highly susceptible to M. brassicae, whereas the commercial hybrids tested were resistant in terms of head foliage consumption and number of larvae per plant. Performance of varieties was similar under natural and artificial infestation although some of them performed differently at each year. Three local varieties (MBG-BRS0057, MBG-BRS0074, and MBG-BRS0452) were highly susceptible at both natural and artificial infestation conditions being MBG-BRS0074 the most damaged variety. Two local varieties (MBG-BRS0402 and MBG-BRS0535) and commercial hybrids were identified as resistant or moderately resistant to M. brassicae. Among them, 'Corazón de Buey' and 'Cabeza negra' were the most resistant and produced compact heads. These varieties could be useful sources of resistance to obtain resistant varieties to M. brassicae or as donors of resistance to other Brassica crops. The possible role of leaf traits, head compactness, and leaf glucosinolate content in relation to M. brassicae resistance is discussed.

Life cycle and attacks of ectoparasites on ruminants during the year in Central Europe: recommendations for treatment with insecticides (e.g., Butox)

The occurrence of ectoparasites on ruminants throughout the yearly seasons was compiled from the literature and from our own experiments that were based on ultraviolet trap catches during the years 2007-2009. The data were listed in tables, which also contained details on the life cycles of flies, mosquitoes, tabanids, midges, simuliids, louse flies, mallophaga, sucking lice, etc. The breeding sites of those ectoparasites were described as well as their potential activity as vector of agents of diseases. Considering the places for overwintering, proposals were made when insecticidal products such as Butox pour-on should be used in order to obtain good rearing results.

Experiments on the ectoparasitic deer ked that often attacks humans; preferences for body parts, colour and temperature

The deer ked (Lipoptena cervi) can fail in its host search. Host search fails when an individual deer ked irreversibly accepts a host unsuitable for its reproduction (e.g. a human) and drops its wings. In northern Europe, the main host of the deer ked is the moose (Alces alces). The deer ked is increasingly causing serious problems for humans (for example, causing deer ked dermatitis) and is considered a threat for the recreational use of forests. The adult deer ked flies in early and mid-autumn to search for a host. Our aims were: (i) to study whether there are ways to avoid deer ked attacks by wearing particular clothing, and (ii) to evaluate deer ked host choice. Using human targets, we explored the cues the deer ked uses for host selection. We studied which part of the host body deer keds target and if body colour and temperature affect their choice. In our experiments, deer keds landed more on dark and red clothing than on white clothing. Moreover, deer keds mostly attacked the upper body parts and preferred the back side of the body over the front side. Finally, deer keds preferred the warmest areas of the host.

Curative activity of insecticides on Rhagoletis pomonella (Diptera: Tephritidae) in apples

Field-based experiments were used to determine the lethal activity of insecticides on apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), eggs and larvae in apple (Malis spp.) fruit. The organophosphates azinphosmethyl and phosmet and the neonicotinoids thiacloprid, acetamiprid, clothianidin, and thiamethoxam showed significant curative activity on the apple maggot postinfestation, when applied topically to apple fruit 24 h postharvest. Of the compounds tested, only phosmet showed significant curative activity on apple maggot when applied 14 d postharvest. The pyrethroid esfenvalerate, oxadiazine indoxacarb, anthranilic diamide chlorantraniliprole, and spinosyns spinosad and spinetoram did not show activity on apple maggot eggs and larvae in fruit. Residue profiles showed that for most compounds, the majority (>85%) of residues were found in the skin and the outside 2 mm of the apple flesh. For the neonicotinoid compounds, however, substantial portions of residues were found to penetrate in and beyond the outer flesh regions, and the total flesh residue recoveries were generally greater than those from the skin. Residues of azinphosmethyl and phosmet were detected in all three flesh regions, with the largest proportions recovered from the skin.

A review of host finding behaviour in the parasitic sea louse, Lepeophtheirus salmonis (Caligidae: Copepoda)

Ectoparasitic sea lice are the most important parasite problem to date for the salmon farming industry in the northern and southern hemispheres. An understanding of host location in the specialist species, Lepeophtheirus salmonis, the most important louse species in the North Atlantic, is now being realized using behavioural in vitro and in vivo bioassays coupled with chemical analysis of fish conditioned waters. Both physical and chemical cues are important in host location. Responses of sea lice to physical cues such as light and salinity may enable them to gather in areas where host fish are likely to be found. Mechanoreception is an important sensory modality in host location and acts by switching on specific behaviours that enable landing on a fish. Chemoreception plays a defining role in host location and recognition. The detection of host kairomones switches on 'host search' behavioural patterns and also induces landing responses whereas non-host kairomones fail to induce attraction or significant landing behaviour. Semiochemicals derived from salmon and also non-host fish have been identified, and may prove useful for the development of integrated pest management strategies, by the introduction of odour traps for monitoring lice numbers, and by the use of stimulo-deterrent diversionary (push:pull) strategies in their control.

Efficacy of a combination of a fipronil-(S)-methoprene spot-on formulation and a deltamethrin-impregnated collar in controlling fleas and sandflies on dogs

This study investigated the use of two commercial products, a deltamethrin-impregnated collar and a fipronil-(S)-methoprene spot-on formulation, in combination to protect dogs against sandflies and fleas when they live in or travel to leishmaniasis-enzootic areas. Interactions, tolerance, and efficacy were evaluated. The combination was well tolerated by the six treated dogs. The antifeeding effect on Phlebotomus perniciosus ranged from 89.6% (day 1) to 99.51% (day 21) and exceeded 95% from day 7 through the end of the study; the mortality effect against P. perniciosus ranged from 87.52% (day 22) to 96.82% (day 15). The combination was 100% effective in controlling Ctenocephalides felis felis infestations for 36 days after treatment. These results suggest that it is feasible and advantageous to combine these two commercial products to protect dogs against sandflies and fleas in leishmaniasis-enzootic areas.

Considerations in developing an integrated pest management programme for control of sea lice on farmed salmon in Pacific Canada

In the development of integrated pest management (IPM) plans for the control of sea lice there are some components that are common to many areas. However, effective plans must be tailored to regionally varying environmental and biological factors affecting the severity of sea lice infections. This paper describes factors that would be involved in the development of an IPM plan for sea lice in the Broughton Archipelago, British Columbia. Temperature, salinity and currents affect the production, dispersion and competence of larvae of sea lice, Lepeophtheirus salmonis (Krøyer), as they develop to the infective copepodid stage. This information can be coupled with oceanographic conditions in the Broughton Archipelago and emerging computer models to define zones of infection where infections of new hosts are most likely. Salinity and temperature depend, in part, on river discharge in estuarine systems. River discharge depends on precipitation, snow pack and ambient temperatures, which can be monitored to help forecast the intensity of sea lice infections associated with both farmed and wild hosts. One of the goals of IPM planning is to reduce reliance on pesticides to avoid development of resistance in targeted parasites and to minimize environmental residues. Recommendations for developing an IPM plan specific to the Broughton Archipelago are provided along with a discussion of the additional information needed to refine IPM plans in this and other areas.

Use of a chitin synthesis inhibitor to control fleas on wild rodents important in the maintenance of plague, Yersinia pestis, in California

A study was designed to test the insect development inhibitors fluazuron and lufenuron for the control of fleas on sylvatic rodents as an adjunct to the control of plague. Historical data of flea burden from 15 prior years of study at Chuchupate Campground, Ventura County, CA, were compared to six years of treatment period data to determine if fluazuron and lufenuron were effective in controlling flea densities. The insect development inhibitors, delivered systemically via a feed cube, reduced flea loads effectively on California ground squirrels (Spermophilus beecheyi), long-eared woodrats (Neotoma macrotis), and mice (Peromyscus spp.) but not on Merriam's chipmunks (Tamias merriami).

[Bedbugs (Heteroptera, Cimicidae): biting again]

Bedbugs have been man's faithful companions from his cave days to the present time. After World War II, improvements in household and personal cleanliness and above all widespread use of insecticidal treatment led to a decline in the prevalence of bedbugs so that they became almost unknown to populations in industrialized countries. However in recent years a resurgence of bedbugs has been reported in North America as well as in most European countries. The purpose of this study is to provide an update on the comeback of bedbugs in France and the world, to discuss their impact on public health, and to consider possible causes for the current resurgence.

Controlling tungiasis in an impoverished community: an intervention study

Background

In Brazil, tungiasis is endemic in some resource-poor communities where various domestic and sylvatic animals act as reservoirs for this zoonosis. To determine the effect of control measures on the prevalence and intensity of infestation of human and animal tungiasis, a repeated cross-sectional survey with intervention was carried out.

Methodology/Principal Findings

In a traditional fishing community in Northeast Brazil, humans and reservoir animals were treated, and premise-spraying using an insecticide was done, while a second fishing community served as a control. Both communities were followed up 10 times during a 12-month period. At baseline, prevalence of tungiasis was 43% (95% confidence interval [CI]: 35%–51%) and 37% (95% CI: 31%–43%) in control and intervention villages, respectively. During the study, prevalence of tungiasis dropped to 10% (95% CI: 8%–13%; p<0.001) in the intervention village, while the prevalence remained at a high level in the control village. However, after one year, at the end of the study, in both communities the prevalence of the infestation had reached pre-intervention levels. Whereas the intensity of infestation was significantly reduced in the intervention community (p<0.001), and remained low at the end of the study (p<0.001), it did not change in the control village.

Conclusion/Significance

Our study shows that a reduction of prevalence and intensity of infestation is possible, but in impoverished communities a long-lasting reduction of disease occurrence can only be achieved by the regular treatment of infested humans, the elimination of animal reservoirs, and, likely, through environmental changes.

Trial Registration

Controlled-Trials.com ISRCTN27670575

Tungiasis is a disease caused by the sand flea Tunga penetrans, a parasite prevalent in many impoverished communities in developing countries. The female sand flea penetrates into the skin of animals and humans where it grows rapidly in size, feeds on the host's blood, produces eggs which are expelled into the environment, and eventually dies in situ. The lesions become frequently superinfected and the infestation is associated with considerable morbidity. Clearly, tungiasis is a neglected disease of neglected populations. We investigated the impact of a package of intervention measures targeted against on-host and off-host stages of T. penetrans in a fishing community in Northeast Brazil. These measures decreased disease occurrence only temporarily, but had a sustained effect on the intensity of the infestation. Since infestation intensity and morbidity are correlated, presumably the intervention also lowered tungiasis-associated morbidity. Control measures similar to the ones used in this study may help to effectively control tungiasis in impoverished communities.

Increasing pesticide-resistant ectoparasitic infections may increase pesticide poisoning risks in children

Head louse and scabies mite infestations are common among pre-school and school-age children, and topical pesticides are frequently prescribed to treat such conditions. Ectoparasite resistance to the safest and most commonly prescribed pyrethrin/pyrethroid pesticides for ectoparasitic infections has, however, been increasing since the 1980s. The increasing resistance of these arthropods to the safest pesticides may lead to greater use of more toxic, alternative pesticides to control infestations and to prevent institutional outbreaks. MEDLINE and Cochrane searches, 1966-2008, were conducted to assess the impact of increasing pesticide resistance on prescribing practices for ectoparasitic infections and to describe the evolving global epidemiology of pediatric poisonings by more toxic pediculicides and miticides, including carbamates, organochlorines, and organophosphates. Pharmacists, physicians, and poison control personnel should be fully informed about increasing pesticide resistance among the most commonly encountered ectoparasites of children and the institutionalized and be prepared to prevent and to treat accidental home and institutional pesticide poisonings with more toxic pesticides.

Bedbug infestations in the news: a picture of an emerging public health problem in the United States

Bedbug (Cimex lectularis) infestations have become a major complaint in all but three states in the United States. Increasing infestations have also been reported in Asia, Australia, Europe, and Canada. Newspaper articles often herald the onset of a new health issue for the public, and they can be used for epidemiological tracking of increasing populations of irritating and potentially serious vectoring pests. This news coverage model is useful in validating the typical spread of a new contagious entity, or in predicting the waves of public reaction to the spread of a new pest or health problem. The authors' analysis covers the years 2001 to 2006, showing the incidence of bedbug news coverage from the East Coast, the Midwest, the South, and the West in the United States. Rural and urban examples are included in a four-year time frame starting with news in the Northeast and ending with an attempt to eradicate the pest from the state of Hawaii.

Investigations on the biology, epidemiology, pathology, and control of Tunga penetrans in Brazil: VII. The importance of animal reservoirs for human infestation

In Brazil tungiasis is endemic in many resource-poor communities, where various domestic and sylvatic animals act as reservoirs for this zoonosis. To determine the role of animal reservoirs in human tungiasis, a cross-sectional study was performed in a traditional fishing community in northeast Brazil. The human and the animal populations were examined for the presence of embedded sand fleas and the prevalence and the intensity of infestation were correlated. The overall prevalence of tungiasis in humans was 39% (95% CI 34-43%). Of six mammal species present in the village, only cats and dogs were found infested. The prevalence in these animals was 59% (95% CI 50-68%). In households, where infested pet animals were present, a higher percentage of household members had tungiasis (42% [95% CI 30-53%] versus 27% [20-33%], p=0.02), and the intensity of the infestation was higher (six lesions versus two lesions, p=0.01). The intensity of infestation in animals correlated with the intensity of infestation in humans (rho=0.3, p=0.02). Living in a household with an infested dog or cat led to a 1.6-fold (95% CI 1.1-2.3, p=0.015) increase in the odds for the presence of tungiasis in household members in the bivariate analysis and remained a significant risk factor in the multivariate regression analysis. The study shows that in this impoverished community tungiasis is highly prevalent in humans and domestic animals. In particular, it underlines the importance to include animals in control operation aiming at the reduction of disease occurrence in the human population.

A comparative evaluation of the speed of kill and duration of efficacy against weekly infestations with fleas on cats treated with fipronil-(S)-methoprene or metaflumizone

Spot-on formulations of metaflumizone and a combination of fipronil-(S)-methoprene were evaluated in adult cats to determine the duration of 24- and 48-hour efficacy and short-term speed of kill against adult cat fleas, Ctenocephalides felis felis. Speed of kill efficacies (at 12, 18, 24, and 48 hours) were assessed against existing (day -1) infestations and against infestations at day 7, and efficacy was assessed 24 and 48 hours after weekly flea infestations through day 42. Cats treated with fipronil-(S)-methoprene had significantly (P<.01) fewer fleas than those treated with metaflumizone at 12 and 18 hours after treatment (day 0) and on the day 7 infestations. Fipronil-(S)-methoprene-treated cats also had significantly (P<.05) fewer fleas than metaflumizone-treated cats for all 24-hour counts from initial treatment on day 0 through infestation day 42 and for the 48-hour counts on day 28 through day 42.

Comparative efficacy of imidacloprid, selamectin, fipronil-(S)-methoprene, and metaflumizone against cats experimentally infested with Ctenocephalides felis

Four active ingredients--imidacloprid selamectin, fipronil-(S)-methoprene, and metaflumizone--were tested to assess the speed of flea kill against existing flea infestations and subsequent reinfestations. Thirty flea-infested cats were allocated to four treatment groups and one untreated control group. Flea counts were performed 6, 18, and 48 hours after treatment (day 0) and 2, 4, and 24 hours after weekly flea reinfestations. Cats were also reinfested with fleas after the 6- and 18-hour counts on day 0 and after the 2- and 4-hour counts on subsequent count days. Imidacloprid provided significantly greater flea kill at diverse time points. At the 24-hour counts, all compounds showed expected and similar high efficacies. On study day 34, imidacloprid showed the highest efficacy at 24 hours after reinfestation, with 90.8% flea reduction compared with 55.7% to 67.4% in the other treatment groups. A single topical application of imidacloprid provided a high efficacy in the early elimination of adult fleas, limiting the risk of pathogen transmission and flea allergy dermatitis.

Diel variation in egg-laying by the freshwater fish louse Argulus foliaceus (Crustacea: Branchiura)

Removal of deposited eggs could be a useful control strategy for the damaging fish ectoparasite Argulus foliaceus, but focused control requires knowledge of egg-laying patterns. Here, we investigated diel changes in the egg-laying behaviour of a natural population of A. foliaceus. Data were collected from 17-28 May 2004. Days were divided into 3 time periods: 06:00-14:00, 14:00-22:00 and 22:00-06:00 h. Significantly more egg clutches were laid from 06:00-14:00 h than during the other 2 time periods, which were not significantly different from each other. Significantly more egg clutches per hour were laid during hours of daylight as compared to hours of darkness. Significantly more egg clutches were laid in the top 1 m of the water column than at the bottom, and this was consistent throughout all 3 time periods. It is suggested that the increase in egg-laying activity during daylight hours may be due to a higher motivation to search for hosts during the night and an increased ability to locate silhouetted egg-laying sites during the day. These data can provide information useful for egg removal and control strategies.

The biology of gyrodactylid monogeneans: the "Russian-doll killers"

This article reviews the history of gyrodactylid research focussing on the unique anatomy, behaviour, ecology and evolution of the viviparous forms while identifying gaps in our knowledge and directions for future research. We provide the first summary of research on the oviparous gyrodactylids from South American catfish, and highlight the plesiomorphic characters shared by gyrodactylids and other primitive monogeneans. Of these, the most important are the crawling, unciliated larva and the spike sensilla of the cephalic lobes. These characters allow gyrodactylids to transfer between hosts at any stage of the life cycle, without a specific transmission stage. We emphasise the importance of progenesis in shaping the evolution of the viviparous genera and discuss the relative extent of progenesis in the different genera. The validity of the familial classification is discussed and we conclude that the most significant division within the family is between the oviparous and the viviparous genera. The older divisions into Isancistrinae and Polyclithrinae should be allowed to lapse. We discuss approaches to the taxonomy of gyrodactylids, and we emphasise the importance of adequate morphological and molecular data in new descriptions. Host specificity patterns in gyrodactylids are discussed extensively and we note the importance of host shifts, revealed by molecular data, in the evolution of gyrodactylids. To date, the most closely related gyrodactylids have not been found on closely related hosts, demonstrating the importance of host shifts in their evolution. The most closely related species pair is that of G. salaris and G. thymalli, and we provide an account of the patterns of evolution taking place in different mitochondrial clades of this species complex. The host specificity of these clades is reviewed, demonstrating that, although each clade has its preferred host, there is a range of specificity to different salmonids, providing opportunities for complex patterns of survival and interbreeding in Scandinavia. At the same time, we identify trends in systematics and phylogeny relevant to the G. salaris epidemics on Atlantic salmon in Norway, which can be applied more generally to parasite epidemiology and evolution. Although much of gyrodactylid research in the last 30 years has been directed towards salmonid parasites, there is great potential in using other experimental systems, such as the gyrodactylids of poeciliids and sticklebacks. We also highlight the role of glacial lakes and modified river systems during the ice ages in gyrodactylid speciation, and suggest that salmon infecting clades of G. salaris first arose from G. thymalli in such lakes, but failed to spread fully across Scandinavia before further dispersal was ended by rising sea levels. This dispersal has been continued by human activity, leading to the appearance of G. salaris as a pathogen in Norway. We review the history and current status of the epidemic, and current strategies for elimination of the parasite from Norway. Finally, we consider opportunities for further spread of the parasite within and beyond Europe.