Number Of Larvae Research Articles

Oviposition preference, larval distribution and impact of the swede midge, Contarinia nasturtii, on growth and yield of canola

The swede midge (Contarinia nasturtii) has become a significant economic pest of canola (Brassica napus L.) in Ontario and an emergent pest in the Prairie provinces. Determining yield impacts of swede midge damage and the growth stage(s) at which canola is most vulnerable or attractive to swede midge will contribute to the development of pest management recommendations throughout the growth of the crop. In four experiments, canola plants were exposed to specific densities of adult swede midge and measures of oviposition, damage and yield were collected. There was a significant positive relationship between female density and total oviposition per plant with a very high capacity for larval numbers on canola; up to ~ 4000. Given a choice of four growth stages, approximately 85% of oviposition occurred on seven-leaf and early bud canola. Given no choice, the high total oviposition on 3-leaf and flowering stages suggests that swede midge will oviposit on less favorable canola growth stages, if no others are present. Damage sustained on primary racemes remained relatively constant over time. However, damage ratings on secondary and tertiary racemes decreased over time in the highest treatment densities, suggesting compensation by the plant. All yield measures, except seed weight per pod, significantly decreased with increasing female density on primary and/or secondary racemes. A density of ~ 0.6 females per plant resulted in 10% reductions in the number of pods and seed weight produced on primary racemes. These results support recommendations for insecticide applications at, or just prior to, the early bud stage.

Survival and Reproduction of Small Hive Beetle (Coleoptera: Nitidulidae) on Commercial Pollen Substitutes

An assay was developed to investigate the potential survival and reproduction of the small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), when provided artificial food resources in managed European honey bee, Apis mellifera Linnaeus (Hymenoptera: Apidae), colonies. Supplemental feeding was done to maintain the health of the hive, initiate comb building, expand colony numbers, and promote pollen foraging. To complement the protein requirement of honey bees, commercial pollen substitutes have been developed and are available for producers. Small hive beetles also exploit the pollen substitutes when present in the hive. Adult beetles were provided with 7 different commercial pollen substitutes and allowed to freely feed and oviposit over a period of 30 d. Beetles that survived the longest on the treatments did not necessarily produce the most larvae. The supplement Bee-Pro® supported the greatest survival, yet produced very low larval numbers. Global Patties® produced the most larvae; however, adult survival was low. This result may have been due to the larvae using all of the food resources in a short amount of time, leaving little to support adult survival. Four of the 7 treatments supported 70% or greater beetle survival for the entire assay period. This study suggests that the protein supplement needs to be readily consumed by the honey bee colony if it is to be effective for pest control. Careful selection of the amount and type of honey bee supplemental diets is important in balancing nutritional needs of bees and reducing potential problems with small hive beetles.

Influence of parasite load on the diagnosis and occurrence of eosinophilia in alcoholic patients infected with Strongyloides stercoralis.

Alcoholic patients are more susceptible to Strongyloides stercoralis infection. The chronic use of alcohol raises the levels of endogenous corticosteroids, which regulates the development of larvae and stimulates the differentiation of rhabditiform into infective filariform larvae, thus inducing internal autoinfection. Therefore, early diagnosis is important to prevent severe strongyloidiasis. The aim of this study was to evaluate the efficacy of parasitological methods, according to the parasite load and the number of stool samples, for diagnosis of S. stercoralis infection, as well the peripheral blood eosinophil count in alcoholic patients. A total of 330 patients were included in this study. The diagnosis was established using three parasitological methods: agar plate culture, Baermann-Moraes method and spontaneous sedimentation. Peripheral eosinophilia was considered when the level was >600 eosinophils/mm3. The agar plate culture (APC) had the highest sensitivity (97.3%). However, the analysis of multiple samples increased the sensitivity of all parasitological methods. The sensitivities of the methods were influenced by the parasite load. When the larval number was above 10, the sensitivity of APC was 100%, while in spontaneous sedimentation the sensitivity reached 100% when the larval number was above 50. In the present study, 15.4% of alcoholic patients infected with S. stercoralis (12/78) had increased peripheral blood eosinophil count (above 600 eosinophils/mm3). For an efficient parasitological diagnosis of S. stercoralis infection in alcoholic patients, repeated examination by two parasitological methods must be recommended, including agar plate culture due to its higher sensitivity. Moreover, S. stercoralis infection was associated with eosinophilia, mostly in patients excreting up to 10 larvae/g faeces.

Anticipatory flexibility: larval population density in moths determines male investment in antennae, wings and testes.

Developmental plasticity provides individuals with a distinct advantage when the reproductive environment changes dramatically. Variation in population density, in particular, can have profound effects on male reproductive success. Females may be easier to locate in dense populations, but there may be a greater risk of sperm competition. Thus, males should invest in traits that enhance fertilization success over traits that enhance mate location. Conversely, males in less dense populations should invest more in structures that will facilitate mate location. In Lepidoptera, this may result in the development of larger antennae to increase the likelihood of detecting female sex pheromones, and larger wings to fly more efficiently. We explored the effects of larval density on adult morphology in the gum-leaf skeletonizer moth, Uraba lugens, by manipulating both the number of larvae and the size of the rearing container. This experimental arrangement allowed us to reveal the cues used by larvae to assess whether absolute number or density influences adult responses. Male investment in testes size depended on the number of individuals, while male investment in wings and antennae depended upon larval density. By contrast, the size of female antennae and wings were influenced by an interaction of larval number and container size. This study demonstrates that male larvae are sensitive to cues that may reveal adult population density, and adjust investment in traits associated with fertilization success and mate detection accordingly.

Challenges of pheromone-based mating disruption of Cydia strobilella and Dioryctria abietella in spruce seed orchards

Seed orchards function as the primary source of high-quality seeds for reforestation in many European countries, but their seed yields can be severely reduced due to seed- and cone-feeding insects. We evaluated various parameters of pheromone-based mating disruption for control of the moths Cydia strobilella and Dioryctria abietella, which are major pests in European Picea abies seed orchards. We applied different types of pheromone dispensers (rubber septa or wax droplets) at different densities and heights, and with different amounts of active components, covering whole orchards or part of an orchard. The efficacy of the treatment was evaluated by analysing male captures in pheromone-baited assessment traps, and presence of larvae in cones. A dramatic decrease (94–100%) in capture of males in traps occurred in all pheromone-treated plots compared to control plots for both moth species. In contrast, a subsequent reduction in larval numbers in cones was only achieved when wax droplets were used as the dispensing formulation at high density and at the highest pheromone dose tested, and only in half of the trials for each pest species. Electrophysiological recordings using antennae of male C. strobilella indicated elevated pheromone concentrations in a treated plot versus a control plot. Our results show that mating disruption has potential to reduce cone damage in spruce seed orchards caused by C. strobilella and D. abietella, but optimisation of the technique is required to achieve consistent and efficient population suppression of these pests.

In vitro efficacy of Duddingtonia flagrans against nematodes of sheep based on in vivo calculations.

Duddingtonia flagrans has been tested as an alternative parasite control, but data from in vitro experiments based on in vivo calculations describing nematophagous fungi predation in nematodes are restricted. The objective of this work was to determine the efficacy of D. flagrans against sheep nematode larvae in vitro using in vivo calculations. Fecal samples were introduced to fungi in different concentrations: 0.0/control; 0.05; 0.1; 0.2; 0.4; 0.8; 1.6; 3.2; and 6.4 g corresponding, respectively, to 583.000; 1.166.000; 2.332.000; 4.664.000; 9.328.000; 18.656.000; 37.312.000 and 74.624.000 chlamydospores/kg of body weight. The material was incubated for 14 days, before the larvae recovery (Assay 1). Assay 2 was carried out with the doses of 0.00625; 0.0125; and 0.025 g. The results showed a negative correlation between fungal concentrations and larval numbers for both assays. The fungus demonstrated an efficacy above 89% in both assays. Thus, we consider that the data from in vitro studies based on in vivo calculations may optimize the fungi quantities for field experiments.

How important are aquatic predators to mosquito larval populations in natural wetlands? A case study from Carolina bays in Georgia

Predation is believed to be an important natural control on larval mosquito populations. However, empirical evidence for predator impacts is lacking, especially from natural wetlands (swamps and marshes). Over a 2-year period, we sampled larval mosquito populations and naturally co-occurring predator assemblages (aquatic invertebrates, fishes) from ten depressional wetlands (Carolina bays) located on a wildlife management area in east central Georgia. We collected a diversity of mosquito larvae and predators (odonates, bugs, beetles, flies, and fishes) from the wetlands, with predator numbers substantially exceeding mosquito larval numbers. However, using a community ecology approach with multivariate ordination and correlation techniques, we found no compelling evidence that these predators were controlling mosquito larval distributions (i.e. significant negative statistical associations were not detected). Those mosquitoes that successfully breed in Carolina bay wetlands (Culiseta melanura, Coquillettidia perturbans, Anopheles crucians) appear well adapted to co-exist with a plethora of naturally occurring predators.

Pond dyes are Culex mosquito oviposition attractants.

BackgroundBritish mosquito population distribution, abundance, species composition and potential for mosquito disease transmission are intimately linked to the physical environment. The presence of ponds and water storage can significantly increase the density of particular mosquito species in the garden. Culex pipiens is the mosquito most commonly found in UK gardens and a potential vector of West Nile Virus WNV, although the current risk of transmission is low. However any factors that significantly change the distribution and population of C. pipiens are likely to impact subsequent risk of disease transmission. Pond dyes are used to control algal growth and improve aesthetics of still water reflecting surrounding planting. However, it is well documented that females of some species of mosquito prefer to lay eggs in dark water and/or containers of different colours and we predict that dyed ponds will be attractive to Culex mosquitoes.MethodsBlack pond dye was used in oviposition choice tests using wild-caught gravid C. pipiens. Larvae from wild-caught C. pipiens were also reared in the pond dye to determine whether it had any impact on survival. An emergence trap caught any adults that emerged from the water. Water butts (80 L) were positioned around university glasshouses and woodland and treated with black pond dye or left undyed. Weekly sampling over a six month period through summer and autumn was performed to quantified numbers of larvae and pupae in each treatment and habitat.ResultsGravid female Culex mosquitoes preferred to lay eggs in dyed water. This was highly significant in tests conducted under laboratory conditions and in a semi-field choice test. Despite this, survivorship in black dyed water was significantly reduced compared to undyed water. Seasonal analysis of wild larval and pupal numbers in two habitats with and without dye showed no impact of dye but a significant impact of season and habitat. Mosquitoes were more successful, with significantly higher numbers of pupae, in the habitat where they had vegetation cover and shade.DiscussionOur study has raised some interesting possibilities; one is that where used, pond dyes may be encouraging mosquitoes to breed in gardens in close proximity to people. Considering the concerns over potential future spread of disease in urban environments, this as well as shading of ponds and water butts, should inform future advice over reducing mosquito breeding and spread.

Analysis of oilseed rape stem weevil chemical control using a damage rating scale.

Rape stem weevil (Ceutorhynchus napi Gyll.) and cabbage stem weevil (C. pallidactylus Marsh.) can cause significant yield losses to oilseed rape (Brassica napus L.), and chemical control is often needed to protect crops from these pests. The efficacy of six insecticides, chlorpyriphos + cypermethrin, bifenthrin, alpha-cypermethrin, pirimiphos-methyl, thiacloprid and tau-fluvalinate, was tested in a 4 year field trial. Besides the standard efficacy analysis expressed through the number of larvae per stem, a damage rating scale was introduced and modelled using a regression model for ordinal categorical data. Compared with the control, expressed through damage rating and larval number, treatments with chlorpyriphos + cypermethrin and bifenthrin, showed higher efficacy in the control of stem weevils compared with alpha-cypermethrin and pirimiphos-methyl. The lowest efficacy was observed in treatments with tau-fluvalinate and thiacloprid. This study showed that a combined efficacy evaluation expressed through both damage rating scale and the count of larvae, supported by an ordinal regression model for data analysis, is indispensable for obtaining accurate results. © 2017 Society of Chemical Industry.

Development and Survival of Spodoptera exigua (Lepidoptera: Noctuidae) on Alternate Crops in Cotton Cropping Pattern, With Implications to Integrated Pest Management.

Spodoptera exigua (Hübner) is a polyphagous pest that shifts its population to different hosts during its life cycle to receive nutritive advantages. Therefore, demographic evaluation of alternate hosts is important for effective pest management. Here, we have evaluated castor (Ricinus communis L.), cauliflower (Brassica oleracea L.), cotton (Gossypium hirsutum L.), okra (Abelmoschus esculentus L.), and spinach (Spinacia oleracea L.) for growth, survival, and population development of S. exigua. Development of early populations of S. exigua is best supported on castor where earlier instars had least mortalities (10%) compared with spinach (36%), although later instars and pupae had significantly higher mortalities (20.8%) on it. Spinach and okra, on the other hand, promote larval survivals in later instars. Little or no differences in stadia lengths were observed during early development of larvae and, interestingly, the longevity of female moths increased significantly when reared on castor, cauliflower, and spinach (12.3, 11.3, and 11.7 d, respectively), resulting into significantly higher fecundity. The survival curves of all five populations have clearly demonstrated a steep early decline in larval numbers when reared on okra and only 60% larvae could survive. These findings conclude that S. exigua when fed on spinach was greatly disadvantaged in terms of growth and development; hence, the pest's field population can be opportunistically controlled by spraying adjacent spinach fields. In addition, the results highlight the vulnerable stages in pest's life cycle in the field where we can apply integrated control strategies for its effective management.

Efficacy of Trichogramma evanescens and Bacillus thuringiensis var. kurstakiin control of Cydia pomonella (L.) in Turkey

This study was conducted to evaluate the effectiveness of Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) release with as well as without Bacillus thuringiensis var. kurstaki (Berliner) in biological control of Cydia pomonella (L.) (Lepidoptera: Tortricidae) in the Galaxy Gala apple variety grafted onto M9 rootstock in 2016. Four treatments were analyzed: releasing T. evanescens alone (TE), applying B. thuringiensis var. kurstaki (BT) alone, applying both (TE + BT), and a control (C) without any application at all. The experiment design entailed randomized blocks with four replicates. In each generation of the egg stage, 100,000 parasitoids per hectare were released twice (1440 parasitoids/plot), with an interval of 7-10 days. In the larval stage, BT was applied twice for the first generation and once for the second. Weekly counts were performed regularly. The decrease in egg count was 52.15% in TE, 58.99% in BT, and 65.46% in TE + BT plots. The decrease observed in larval numbers was 68%, 73.33%, and 94.66%, respectively. Egg parasitization rates varied between 58.64% and 69.79%. At harvest, fruit infestation rates were 9.66% and 8.33% in TE and BT plots and just 2.0% in the TE + BT plot, versus 34% in the control plot. Promising results were achieved in biological control of C. pomonella when TE was combined with BT. The combined treatment of both biological control agents significantly decreased the population of the pests and crop damage. The natural enemy alone was not effective in keeping the population below the economic threshold level.

Density dependence and temporal plasticity of competitive interactions during utilisation of resources by a community of lepidopteran stemborer species

AbstractInteractions within and between species sharing the same resources are characterised by competition or facilitation, and can be influenced by factors such as larval numbers and phenotypic plasticity of the interactions. The effect of larval density on the survival and relative growth rate of the stemborers Busseola fusca (Fuller) and Sesamia calamistis Hampson (both Lepidoptera: Noctuidae), and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) were studied, as well as the temporal plasticity of their competitive interactions. These stemborers attack maize crops (Zea mays L.) (Poaceae) in sub‐Saharan Africa. Experiments were conducted in the laboratory under controlled conditions at the optimum development temperature (25 °C) for the three species. Surrogate stems filled with artificial diet were intra‐ and interspecifically infested with larvae of each species. The effect of larval density on competition was studied at low (six larvae) and high (12 larvae) levels of infestation, whereas the temporal plasticity of competition was evaluated at 7, 14, 21, or 28 days after infestation. The two experiments involved single‐ and multi‐species infestation treatments. Larval numbers and wet mass in each artificial stem were recorded in each experiment. Survival and relative growth rate of the three species were significantly higher at low‐infestation levels when facing either intra‐ or interspecific competition. The intensity of competition was also temporally plastic among the species and increased as the duration of competition increased. These results are discussed in terms of general infestations of cereal crops by borers.

Evolution of elaborate parental care: phenotypic and genetic correlations between parent and offspring traits.

The evolution of elaborate forms of parental care is an important topic in behavioral ecology, yet the factors shaping the evolution of complex suites of parental and offspring traits are poorly understood. Here, we use a multivariate quantitative genetic approach to study phenotypic and genetic correlations between parental and offspring traits in the burying beetle Nicrophorus vespilloides. To this end, we recorded 2 prenatal traits (clutch size and egg size), 2 postnatal parental behaviors (direct care directed toward larvae and indirect care directed toward resource maintenance), 1 offspring behavior (begging), and 2 measures of breeding success (larval dispersal mass and number of dispersing larvae). Females breeding on larger carcasses provided less direct care but produced larger larvae than females breeding on smaller carcasses. Furthermore, there were positive phenotypic correlations between clutch size, direct, and indirect care. Both egg size and direct care were positively correlated with dispersal mass, whereas clutch size was negatively correlated with dispersal mass. Clutch size and number of dispersed larvae showed genetic variance both in terms of differences between populations of origin and significant heritabilities. However, we found no evidence of genetic variance underlying other parental or offspring traits. Our results suggest that correlations between suites of parental traits are driven by variation in individual quality rather than trade-offs, that some parental traits promote offspring growth while others increase the number of offspring produced, and that parental and offspring traits might respond slowly to selection due to low levels of additive genetic variance.

Field Monitoring and Efficacy of Entomopathogenic Nematodes Against Chamomile Stem Weevil Microplontus rugulosus and Chamomile Smooth Beetle Olibrus aeneus Under Greenhouse Conditions

Chamomile Matricaria recutita (L.) is an ancient healing plant; it is used for a sore stomach, a mild laxative, anti-inflammatory and a gentle sleep aid. Chamomile plants are infested by chamomile stem-weevil Microplontus rugulosus (Col., Curculionidae) and chamomile smooth beetle Olibrus aeneus (Col., Phalacridae), and can lead to a high reduction in chamomile yield. This work aimed to survey M. rugulosus and O. aeneus by different monitoring methods as well as to manage them by using entomopathogenic nematodes. Sweep nets, water traps, and dissecting the chamomile stems and flowers were used to monitor for M. rugulosus and O. aeneus. Chamomile insects were collected from naturally infested plants moved from the field to the greenhouse. Management of chamomile insects was conducted using three strains of entomopathogenic nematodes; while the control plants were sprayed only with water. Each strain was replicated three times and each replicate included 50 chamomile plants (combined total was 150 for each strain). Three treatment dates were carried out in May, June and July; the first one was mainly for controlling stem weevil, while the other two dates were for smooth beetle. The results showed that 70–80 % of stems had damage and symptoms of stem weevils. Thirty percents from the investigated plants were larvae free of smooth beetle; whiles 70 % was infested with different classifications (e. g. 1, 2, 3, 4 or more than 4 larvae/blooms). The results confirm that smooth beetle infestation and larval numbers were higher in May and June than July. Steinernema carpocapsae had more efficiency than S. feltiae and Heterorhabditis bacteriophora in controlling both insects. Entomopathogenic nematodes could be one of the effective management strategies to control these insects in the chamomile fields.

Sea lice vaccine development based on an immunogenic peptide derived from the ribosomal protein P0

Sea lice (Copepoda, Caligidae) are the most widely distributed marine pathogens in the salmon industry. Vaccination is considered an efficient, environmentally safe and economically sustainable alternative for control of ectoparasite infestations. Although emerging sea lice proteins have been identified recently, and have been proposed as potential targets for generating protective molecules, only a limited number of them have been evaluated in vaccine trials with unsuccessful results. On the other hand, more than 80 proteins are found in eukaryotic ribosomes. The protein P0 is essential for the assembly of the 60S ribosomal subunit and essential for cell viability. A vaccinationchallenge trial with an immunogenic peptide of Rhipicephalus sanguineus protein P0 reduced survival of ticks with an overall efficacy of 90%, suggesting that it might be a promising antigen candidate for the control of ectoparasite. We have identified an immunogenic region of the ribosomal protein P0 from Caligus rogercresseyi and Lepeophtheirus salmonis that is not very conserved compared to host P0. We developed several vaccine candidates based on this peptide and produced in E. coli. These antigens were able to elicit a high specific antibody response after intraperitoneal (ip) immunization using tilapia as teleost fish model. It has been shown that ip immunization with some antigens cannot significantly reduce larval lice numbers despite enhanced specific antibody titers were raised. In this context, we have been developed for first time several tools to monitor tilapia immune response (IgT, IFN-γ, IL-4, CD154) to vaccination in order to perform a more complete evaluation of the impact of the vaccinate candidates on the fish immune system. These findings will be finally validated in an immunization-challenge trial in Salmo salar. The overall results are relevant in the development of an effective vaccine against sea lice.

New method for rapidly estimating population densities of the concealed wood-borerMonochamus alternatus(Coleoptera: Cerambycidae) in the field

To rapidly estimate pine sawyer, Monochamus alternatus Hope, population densities in forests, the vertical distributions of M. alternatus oviposition sites and larvae on infested Masson pines (Pinus massoniana Lamb.) were studied. Results showed that the number of oviposition sites on sections of trunks between 0 and 2 m above ground was significantly greater than on sections of trunk above 2 m, and the vertical distribution had a significant logarithmic relationship with trunk height. The larval number of M. alternatus on dead infested trees had a significant difference among heights of trunks. Sections on trunks at 2–4 m usually contained the largest number of M. alternatus larvae, while the number of larvae on trunks above 10 m declined significantly, as well as in the 1 m section of trunk at the base. The vertical distribution of M. alternatus larvae on dead infested pines showed a distinct parabolic relationship with trunk height. The number of oviposition sites of M. alternatus on infested Masson pine trunks revealed a significant exponential relationship with the diameter at breast height (DBH) of trees. A significant positive linear relationship also was observed between M. alternatus larval number and DBH on the host pine trees, as well as between the numbers of larvae and oviposition sites on an individual tree. The total number of larvae in an infested tree could be calculated easily using an established equation, through counting the number of oviposition sites at 3–4 m of trunk aboveground. This study developed a practical method for rapid estimation of M. alternatus populations.

Insecticides Evaluated as Regulatory Immersion Treatments to Eliminate Third-Instar Japanese Beetles (Coleoptera: Scarabaeidae) from Small-Diameter Field-Grown Nursery Plants

Abstract Japanese beetles, Popillia japonica Newman, are a quarantine issue for nursery shipments to certain U.S. states. The Domestic Japanese Beetle Harmonization Plan (DJHP) allows balled and burlapped (B&B) root ball immersion in chlorpyrifos or bifenthrin for P. japonica certification. Study objectives were: (a) to evaluate multiple insecticides as potential regulatory dips against third-instar P. japonica in 30-cm B&B, and (b) to determine the lowest effective rates. Tests were performed fall and spring from 2003 to 2007. All insecticide treatments reduced larval numbers compared with the untreated check treatment, with the exception of chlorantraniliprole and the lowest rate of trichlorfon in a fall test. Bifenthrin, carbaryl, chlorpyrifos, clothianidin, and trichlorfon and bifenthrin + imidacloprid were the most effective insecticides. Larval numbers in acephate, deltamethrin, lambda-cyhalothrin, imidacloprid, and cyfluthrin + imidacloprid treatments exceeded DJHP requirements at rates evaluated....

Prevalence of pasture-associated metazoal endoparasites in Bavarian dairy goat herds and farmers' approaches to parasite control.

The majority of dairy goat farms in Bavaria operate pasture-based systems. Endoparasites are therefore a common problem affecting health and productivity of these herds. Pooled faecal samples from 37 commercial dairy goat farms in Bavaria were examined by modified McMaster, flotation, sedimentation and Baermann funnel techniques. In addition, a questionnaire was used to gather information on farmers' perceptions and parasite management efforts. The average trichostrongyle faecal egg count across the 37 farms was 620 epg, with a median of 450 epg (1st quartile: 135 epg; 3rd quartile: 930 epg; range: < 30 to 3090 epg). Fasciola hepatica eggs were detected on four farms, Moniezia expansa eggs on one, Muellerius capillaris larvae on 13 and Dicrocoelium dendriticum eggs in none of the samples. Following coproculture third stage larvae of trichostrongyle species were identified morphologically. Sufficient larval numbers were obtained from samples from 23 farms. Haemonchus spp. was the most abundant larval genus and accounted for 30.4% of all larvae examined (n = 4868), followed by Trichostrongylus spp. (27.5%), Teladorsagia spp. (21.8%) and Oesophagostomum spp./Chabertia spp. (19.0%; these two genera were not differentiated). Further nematodes were identified according to their egg morphology: Nematodirus spp were present on nine farms, Skrjabinema spp. on nine, Trichuris spp. on five and Strongyloides spp. were not detected in any of the samples. The questionnaire results indicated a widespread lack of farmer awareness of appropriate parasite management and treatment measures. Farmer and veterinary education is therefore important to avoid future resistance problems caused by under-dosing or inappropriate treatments.

Mountain pine beetle (Dendroctonus ponderosae) can produce its aggregation pheromone and complete brood development in naïve red pine (Pinus resinosa) under laboratory conditions

Mountain pine beetle (Dendroctonus ponderosae Hopkins; Coleoptera: Curculionidae, Scolytinae) has killed millions of hectares of lodgepole pine (Pinus contorta Douglas ex Loudon) forest in western Canada, where it has recently established in the novel host jack pine (Pinus banksiana Lamb.) and threatens naïve red pine (Pinus resinosa Aiton) forests as the current outbreak expands eastward. It is therefore crucial to understand whether red pine is a suitable host for D. ponderosae. Host suitability was assessed by comparing the ability of beetles to produce pheromones and complete their development in red pine bolts inoculated with mating beetle pairs. We detected two of four primary pheromones, including trans-verbenol and verbenone, but not exo-brevicomin or frontalin. Beetle brood successfully developed in bolts, with reproductive parameters (e.g., female and larval galleries, pupal chamber, and number of broods emerged per mated pair of adults) that were similar to those reported from the beetle’s historical host lodgepole pine and the novel host jack pine. These results provide initial evidence that red pine is a suitable host for D. ponderosae. However, it is unclear how either low concentrations or an absence of exo-brevicomin, frontalin, and the synergistic monoterpene myrcene could affect host colonization and establishment of beetles.

Establishing the discriminating concentration for permethrin and fipronil resistance in Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae), the brown dog tick.

Rhipicephalus sanguineus (Latreille), the brown dog tick, is a veterinary canine and urban pest. These ticks have been found to develop resistance and tolerance to the two commonly used acaricides permethrin and fipronil respectively. We have developed a discriminating concentration that can be used for rapid detection of permethrin and fipronil resistance in brown dog tick populations. The availability of a discriminating concentration for the brown dog tick provides an inexpensive and rapid resistance diagnostic technique that can be used to guide tick management plans for companion animals and aid in the selection of environmental treatment options. Establishing the discriminating concentration for permethrin and fipronil in brown dog ticks enables a resistant:susceptible screening. For permethrin the discriminating concentration was set at 0.19%, and for fipronil at 0.15%. Three additional diagnostic concentrations were chosen to evaluate resistance levels when larval tick numbers were available for screening. Future tick submissions from residences and kennel facilities can be subjected to a single chemical concentration to diagnose resistance, which minimizes time, costs and tick rearing requirements and guides effective control plans. With the standardized use of larval ticks, a client-submission quantity of ideally five engorged females would provide sufficient larval numbers to utilize this technique. © 2015 Society of Chemical Industry.