The skin is the primary feeding site of ticks that infest livestock animals such as cattle. The highly specialised functions of skin at the molecular level may be a factor contributing to variation in susceptibility to tick infestation; but these remain to be well defined. The aim of this study was to investigate the bovine skin transcriptomic profiles of tick-naïve and tick-infested cattle and to uncover the gene expression networks that influence contrasting phenotypes of host resistance to ticks. RNA-Seq data was obtained from skin of Brangus cattle with high (n = 5) and low (n = 6) host resistance at 0 and 12 weeks following artificial tick challenge with Rhipicephalus australis larvae. No differentially expressed genes were detected pre-infestation between high and low resistance groups, but at 12-weeks there were 229 differentially expressed genes (DEGs; FDR < 0.05), of which 212 were the target of at least 1866 transcription factors (TFs) expressed in skin. Regulatory impact factor (RIF) analysis identified 158 significant TFs ( P < 0.05) of which GRHL3 , and DTX1 were also DEGs in the experiment. Gene term enrichment showed the significant TFs and DEGs were enriched in processes related to immune response and biological pathways related to host response to infectious diseases. Interferon Type 1-stimulated genes, including MX2 , ISG15 , MX1 , OAS2 were upregulated in low host resistance steers after repeated tick challenge, suggesting dysregulated wound healing and chronic inflammatory skin processes contributing to host susceptibility to ticks. The present study provides an assessment of the bovine skin transcriptome before and after repeated tick challenge and shows that the up-regulation of pro-inflammatory genes is a prominent feature in the skin of tick-susceptible animals. In addition, the identification of transcription factors with high regulatory impact provides insights into the potentially meaningful gene–gene interactions involved in the variation of phenotypes of bovine host resistance to ticks.

BACKGROUNDThe demand for protein obtained from animal sources is growing rapidly, as is the necessity for sustainable animal feeds. The use of black soldier fly larvae (BSFL) reared on organic side streams as sustainable animal feed has been receiving attention lately. This study assessed the ability of near-infrared spectroscopy (NIRS) combined with chemometrics to evaluate the nutritional profile of BSFL instars (fifth and sixth) and frass obtained from two different diets, namely soy waste and customised bread-vegetable diet. Partial least squares (PLS) regression with leave one out cross-validation was used to develop models between the NIR spectral data and the reference analytical methods.RESULTSCalibration models with good [coefficient of determination in calibration (Rcal2): 0.90; ratio of performance to deviation (RPD) value: 3.6] and moderate (Rcal2: 0.76; RPD value: 2.1) prediction accuracy was observed for acid detergent fibre (ADF) and total carbon (TC), respectively. However, calibration models with moderate accuracy were observed for the prediction of crude protein (CP) (Rcal2: 0.63; RPD value: 1.4), crude fat (CF) (Rcal2: 0.70; RPD value: 1.6), neutral detergent fibre (NDF) (Rcal2: 0.60; RPD value: 1.6), starch (Rcal2: 0.52; RPD value: 1.4), and sugars (Rcal2: 0.52; RPD value: 1.4) owing to the narrow or uneven distribution of data over the range evaluated.CONCLUSIONThe near-infrared (NIR) calibration models showed a good to moderate prediction accuracy for the prediction of ADF and TC content for two different BSFL instars and frass reared on two different diets. However, calibration models developed for predicting CP, CF, starch, sugars and NDF resulted in models with limited prediction accuracy. (c) 2023 Society of Chemical Industry.

BACKGROUND:Flystrike, primarily caused by Lucilia cuprina, is a major health and welfare issue for sheep wool industries. Current chemical-based controls can have limited effectiveness due to the emergence of resistance in the parasite. RNA interference (RNAi), which uses double-stranded RNA (dsRNA) as a trigger molecule, has been successfully investigated for the development of innovative pest control strategies. Although RNAi offers great potential, the efficient identification, selection of target genes and delivery of dsRNA represent challenges to be overcome for the successful application of RNAi for control of L. cuprina. RESULTS:A primary L. cuprina (blowfly) embryo cell line (BFEC) was established and confirmed as being derived from L. cuprina eggs by PCR and amplicon sequencing. The BFECs were successfully transfected with plasmids and messenger RNA (mRNA) expressing fluorescent reporter proteins and dsRNA using lipid-based transfection reagents. The transfection of dsRNA into BEFC in this study suggested decreased mRNA levels of target gene expression, which suggested RNAi-mediated knockdown. Three of the dsRNAs identified in this study resulted in reductions of in target gene mRNA levels in BFEC and loss of biological fitness by L. cuprina larvae in a feeding bioassay. CONCLUSION:This study confirms that the novel BFEC cell line can be used to improve the efficacy of dsRNA-mediated screening to accelerate the identification of potential target genes in the development of RNAi mediated control approaches for L. cuprina. The research models established in this study are encouraging with respect to the use of RNAi as a blowfly control method, however further improvement and validation are required for field applicationsnot prefect, and could be ongoing developing. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Haematobia irritans exigua, commonly known as buffalo fly, is the major hematophagous ectoparasite of north Australian cattle herds. Lesions associated with buffalo fly infestation are generally alopecic, hyperkeratotic, or scab encrusted wounds with variable hemorrhagic ulceration. Buffalo flies can transmit a filarial nematode, Stephanofilaria sp., which has been implicated in the pathogenesis of buffalo fly lesions, but Stephanofilaria infection has not been detected in all lesions suggesting that other causal factors may be involved. This study characterized the pathology of buffalo fly lesions to identify the role of Stephanofilaria in lesion development, as well as to identify other potential agents. Lesion biopsies were collected from north and south Queensland and tested for the presence of Stephanofilaria by qPCR. Each lesion was scored grossly (0–4) for hemorrhage, ulceration, exudation, and alopecia. Lesions were also scored microscopically (0–4) for epidermal and dermal damage and inflammatory characters. Stephanofilaria infection was detected in 31% of lesion biopsies. Grossly, Stephanofilaria-infected lesions had significantly larger lesion area and higher scores for alopecia and hyperkeratosis than lesions where no nematodes were found (P < 0.05). Histologically, epidermal, dermal, and adnexal damage was significantly higher in Stephanofilaria infected lesions than lesions without nematodes. Eosinophils, macrophages, and lymphocytes were significantly more abundant in Stephanofilaria positive lesions as compared to negative lesions. This study also noted bacterial infection with colonies of coccoid bacteria, observed in skin sections from 19 lesions. Grossly, lesions with bacterial infection had significantly higher ulceration scores compared to Stephanofilaria positive lesions, and histologically epidermal disruption was significantly greater in bacteria-infected lesions. We found no evidence of bacteria or Stephanofilaria infection in 49% of the lesions assessed and tissue damage patterns and eosinophilic inflammation suggested hypersensitivity to buffalo fly feeding as a possible cause of these lesions. These findings suggest that although the presence of Stephanofilaria infection may increase the severity of lesion pathology, it is not essential for lesion development. These outcomes also suggest a potential role of bacteria and hypersensitivity in pathogenesis of some lesion. A better understanding of buffalo fly lesion etiology will contribute to the optimal treatment and control programmes.

Background Disease emergence and production loss caused by cattle tick infestations have focused attention on genetic selection strategies to breed beef cattle with increased tick resistance. However, the mechanisms behind host responses to tick infestation have not been fully characterised. Hence, this study examined gene expression profiles of peripheral blood leukocytes from tick-naive Brangus steers ( Bos taurus x Bos indicus ) at 0, 3, and 12 weeks following artificial tick challenge experiments with Rhipicephalus australis larvae. The aim of the study was to investigate the effect of tick infestation on host leukocyte response to explore genes associated with the expression of high and low host resistance to ticks. Results Animals with high (HR, n = 5) and low (LR, n = 5) host resistance were identified after repeated tick challenge. A total of 3644 unique differentially expressed genes (FDR < 0.05) were identified in the comparison of tick-exposed (both HR and LR) and tick-naive steers for the 3-week and 12-week infestation period. Enrichment analyses showed genes were involved in leukocyte chemotaxis, coagulation, and inflammatory response. The IL-17 signalling, and cytokine-cytokine interactions pathways appeared to be relevant in protection and immunopathology to tick challenge. Comparison of HR and LR phenotypes at timepoints of weeks 0, 3, and 12 showed there were 69, 8, and 4 differentially expressed genes, respectively. Most of these genes were related to immune, tissue remodelling, and angiogenesis functions, suggesting this is relevant in the development of resistance or susceptibility to tick challenge. Conclusions This study showed the effect of tick infestation on Brangus cattle with variable phenotypes of host resistance to R. australis ticks . Steers responded to infestation by expressing leukocyte genes related to chemotaxis, cytokine secretion, and inflammatory response. The altered expression of genes from the bovine MHC complex in highly resistant animals at pre- and post- infestation stages also supports the relevance of this genomic region for disease resilience. Overall, this study offers a resource of leukocyte gene expression data on matched tick-naive and tick-infested steers relevant for the improvement of tick resistance in composite cattle.

The growing world population accompanied by urbanisation and improved economies has resulted in an increased demand for diets rich in animal proteins. The rearing of livestock by existing practices is also becoming increasingly difficult due to changing environmental conditions. The use of black soldier fly larvae (BSFL) grown on organic side streams (bioproducts) as feed for animals presents a sustainable alternative to conventional feed ingredients. The nutritional and compositional profile of BSFL reared on organic side streams and their potential to be used as animal feed has been extensively explored. However, little information is available on the chemical safety of BSFL reared on organic side streams. This review addresses the chemical safety hazards of BSFL reared on substrates spiked with different chemical contaminants, including heavy metals, mycotoxins, pesticides, and pharmaceuticals. BSFL were observed to excrete mycotoxins and were able to reduce the concentration of pesticides and pharmaceutical compounds in the substrate. Certain heavy metals were found to be accumulated in BSFL when grown on spiked substrate. Initial studies have also indicated that the growth parameters and composition of BSFL are not altered by the presence of microplastics and organic pollutants in the substrate. Information about these feed-safety issues will assist in developing regulatory frameworks and appropriate processing methods to mitigate these hazards, thereby providing a framework of risks for the commercialisation of BSFL destined for animal feed.

Fleece rot develops following prolonged wetting of sheep when bacterial proliferation in wool and on skin induces exudation of serum proteins onto the skin surface and causes damage to wool follicles and fibres. These processes create an attractive environment for blowflies to lay eggs, leading to body strike. Current reliance on insecticides for prevention and treatment of fly strike is being increasingly challenged by development of insecticide resistance. This review examines the large body of past research on the bacterial causes of fleece rot, the genetics of sheep susceptibility and resistance, the characteristics of the resulting immune defence reactions, and attempts to control fleece rot by vaccination. The high dependence on weather conditions for expression of fleece rot hampers studies on the disease. Normal skin and wool are populated by a dynamic microbial community. During adverse environmental conditions, natural resistance to fleece rot associated with physical characteristics of wool and skin can be overwhelmed and a complex mix of bacteria flourishes. Prolonged hydration alone, and in combination with bacterial exoproducts, induces dermatitis and exudation of immunoglobulins and other serum proteins onto the skin surface. Pathogens do not usually penetrate the epidermis. Nonetheless, during prolonged skin hydration, sheep can become sensitised to fleece rot pathogens and produce antibodies. Antibody titres rise late within a typical (3 week) case of fleece rot. High naturally acquired antibody titres may contribute to resistance to fleece rot. In contrast to some evidence for a protective role of antibody, there is little evidence for innate or adaptive cellular immune responses contributing to protection against fleece rot pathogens. Previous attempts to develop vaccines have met with mixed success. Nonetheless, there remain prospects for development of a new vaccine to control fleece rot. Further knowledge on the microbial ecology of normal and wet skin would assist this endeavour and may help identify other control strategies.

Previous studies have applied genomics and transcriptomics to identify immune and genetic markers as key indicator traits for cattle tick susceptibility/resistance; however, results differed between breeds, and there is lack of information on the use of host proteomics. Serum samples from Santa Gertrudis cattle (naïve and phenotyped over 105 days as tick-resistant [TR] or tick-susceptible [TS]) were used to conduct differential abundance analyses of protein profiles. Serum proteins were digested into peptides followed by identification and quantification using sequential window acquisition of all instances of theoretical fragment ion mass spectrometry. Before tick infestation, abundance of 28 proteins differed significantly (adjusted P < 10-5 ) between TR and TS. These differences were also observed following tick infestation (TR vs TS) with a further eight differentially abundant proteins in TR cattle, suggesting possible roles in adaptive responses. The intragroup comparisons (TS-0 vs TS and TR-0 vs TR) showed that tick infestation elicited quite similar responses in both groups of cattle, but with relatively stronger responses in TR cattle. Many of the significantly differentially abundant proteins in TR Santa Gertrudis cattle (before and after tick infestation) were associated with immune responses including complement factors, chemotaxis for immune cells and acute-phase responses.

Flystrike remains a serious financial and animal welfare issue for the sheep industry in Australia despite many years of research into control methods. The present paper provides an extensive review of past research on flystrike, and highlights areas that hold promise for providing long-term control options. We describe areas where the application of modern scientific advances may provide increased impetus to some novel, as well as some previously explored, control methods. We provide recommendations for research activities: insecticide resistance management, novel delivery methods for therapeutics, improved breeding indices for flystrike-related traits, mechanism of nematode-induced scouring in mature animals. We also identify areas where advances can be made in flystrike control through the greater adoption of well-recognised existing management approaches: optimal insecticide-use patterns, increased use of flystrike-related Australian Sheep Breeding Values, and management practices to prevent scouring in young sheep. We indicate that breeding efforts should be primarily focussed on the adoption and improvement of currently available breeding tools and towards the future integration of genomic selection methods. We describe factors that will impact on the ongoing availability of insecticides for flystrike control and on the feasibility of vaccination. We also describe areas where the blowfly genome may be useful in providing impetus to some flystrike control strategies, such as area-wide approaches that seek to directly suppress or eradicate sheep blowfly populations. However, we also highlight the fact that commercial and feasibility considerations will act to temper the potential for the genome to act as the basis for providing some control options.

Heavy infestations of the blood-sucking gastrointestinal nematodes, Haemonchus contortus can cause severe anaemia in sheep and leakage of blood into the faeces, leading to morbidity and mortality. Early and accurate diagnosis of infections is critical for timely treatment of sheep, minimizing production and sheep welfare impacts. In pursuit of a quick and easy measure of H. contortus infections, we investigated the use of portable visible near infrared spectrometers for detecting the presence of haemoglobin in sheep faeces as an indicator of H. contortus infection. Calibration models built within the 400–600 nm region by partial least square regression resulted in acceptable prediction accuracies (r 2 p > 0.70 and root mean squared error of prediction <2.64 µg Hb mg −1 faeces) for haemoglobin quantification using two spectrometers. The prediction results from support vector machine regression further improved the prediction of haemoglobin in moist sheep faeces (r 2 p > 0.87 and root mean squared error of prediction <2.00 µg haemoglobin mg −1 faeces). Based on a threshold for anthelmintic treatment of 3 µg Hb mg −1 faeces, both the partial least square and support vector machine models showed high sensitivity (89%) and high specificity (>77%). The specificity of the prediction model for detecting haemoglobin in sheep faeces may be improved by adding more variations in faecal composition into the calibration model. Our success in detecting haemoglobin in sheep faeces, following minimal sample preparation, suggests that with further development, vis–near infrared spectroscopy can provide a sensitive and convenient method for on-farm diagnosis of H. contortus infections.

Buffalo flies Haematobia exigua de Meijere were introduced to Australia in 1838 and have become major cattle pests in Australia's northern cattle industries.They have been steadily expanding their range southward and their spread is likely to be further facilitated by climate change.Control programmes consisting of compulsory chemical treatments and regulated cattle movements have proven unsuccessful in preventing the spread of buffalo flies and, without area-wide intervention, they are likely to become major cattle pests in Australia's southern beef and dairy industries.Buffalo flies do not have a pupal overwintering strategy but survive winter in localised foci of slowly cycling low level populations of flies.Populations increase and spread to infest surrounding areas when weather becomes favourable in summer.This suggests the potential for an area-wide control approach, targeting overwintering foci of the flies.A project has been initiated to transinfect buffalo flies with Wolbachia, determine the effects of Wolbachia infection in the flies, and assess the feasibility of control by Wolbachia-based approaches directly targeting overwintering foci of the flies.

New chemical formulations for flystrike control are required to support the phaseout of mulesing and because of the development of resistance to the most widely used flystrike control compounds. Control of sheep lice has suffered similar resistance problems and remains an issue in the sheep industries. Nanotechnology offers a means of providing extended and ‘softer’ protection of sheep against flystrike and lice. This project is designing and testing unique silica nanocapsule formulations with spikes on the particle surface and purpose-designed release characteristics to give prolonged periods of protection against flystrike and lice, with minimal residues and offtarget effects. This will provide new, labour efficient, options for managing flystrike in unmulesed sheep and countering resistance in sheep blowflies and lice.

Biopesticides, such as spinosad, are a new-generation of ecofriendly pesticides in livestock industry. However, spinosad suffers from short duration of effectiveness and low potency in field conditions. Herein we report the development of a new nanospinosad design with dual adhesion and protection functions. Silica nanoparticles with spiky nanotopography loaded with spinosad possess rough surfaces. When applied topically, this nanospinosad formulation exhibited enhanced adhesion to both cattle hair and pest surface. The dual adhesion property led to significantly higher pest mortality toward tick (Rhipicephalus microplus, an ectoparasite) than a nanospinosad formulation using nanoparticles with smooth surface and a benchmark commercial product. The adhesion performance was further quantitatively measured using rainfastness test. Moreover, solar radiation test revealed that the nanospinosad exhibited >10 times higher photostability over the commercial product. This work paves the way toward the development of high performance nanobiopesticides for sustainable agricultural applications.

Animal health measures mainly rely on vaccination or chemical control for major pests and pathogens, causing issues of residue, toxicity and development of resistance. For example, control of Sheep flystrike and lice-infestation affecting the Australia’s sheep/wool industry (>3.5 B) have developed resistance to nearly all control chemicals used in the past. Topicals RNAi provides an innovative clean-green, non-toxic, environmentally sustainable biological control solution. Biodegradable clay particles as carriers can be used to deliver double stranded RNA (dsRNA), the key trigger molecule of RNA interference pathway. As an early proof of concept, we investigated the stability dsRNA loaded on two types of Clay particles: Clay 1 (releases dsRNA under acidic conditions) and Clay 2 (releases dsRNA under alkaline conditions) on cattle hide. Cattle skin was treated with Cy3 labelled dsRNA alone and Cy3 labelled dsRNA loaded on Clay1 or Clay2. The skin samples treated with the Cy3 formulations were imaged using confocal microscopy. Once imaged, the skin samples were washed and stored at room temperature for 5 days, later the samples were re-imaged to detect the fluorescent signal (Figure 1). The dsRNA loaded on clay particles was stable unlike naked Cy3-dsRNA which degraded and was not visible after washing. This increased inherent stability of the dsRNA molecules, combined with the environmental stability afforded by the Clay particles, offers promise to provide a sustainable solution for animal health. Topical RNAi can reduce reliance on trade withholding periods of meat/wool without chemical residues, enhance animal welfare and increase production of premium quality meat/wool, improve export potential, competitiveness and long-term profitability of livestock industry.

BACKGROUND Effective control of house fly, Musca domestica (L.), populations currently relies on the use of chemical insecticides in most situations. Entomopathogenic fungi such as Metarhizium anisopliae (Metschn.) Sorokin may provide an alternative to chemicals and their efficacy may be enhanced by autodissemination amongst flies. This study assessed the capacity of M. anisopliae for transmission between adult M. domestica flies and the effects of infection on the fecundity of females. RESULTS Metarhizium anisopliae was transmitted between adult M. domestica with 91.67-100% mortality resulting across the three ratios of infected: non-infected flies tested (1:2, 1:5 and 1:10). The mean lethal time (LT50 ) for female recipients mixed with infected male donor flies at the three ratios was 3.95, 4.79 and 5.65 days, respectively, whereas for male recipients mixed with infected female donors at the same ratios the LT50 was 4.98, 5.98 and 7.44 days, respectively. Infection with M. anisopliae significantly reduced the reproductive capacity of female flies during the first 4 days of infection, with 25% fewer eggs oviposited by infected flies than by those that were uninfected. CONCLUSION Autodissemination among house flies and reduction in oviposition in the early stages of infection could contribute significantly to the effectiveness of M. anisopliae used in biocontrol programmes. © 2017 Society of Chemical Industry.

Organelle genome fragmentation has been found in a wide range of eukaryotic lineages; however, its use in phylogenetic reconstruction has not been demonstrated. We explored the use of mitochondrial (mt) genome fragmentation in resolving the controversial suborder-level phylogeny of parasitic lice (order Phthiraptera). There are approximately 5000 species of parasitic lice in four suborders (Amblycera, Ischnocera, Rhynchophthirina, and Anoplura), which infest mammals and birds. The phylogenetic relationships among these suborders are unresolved despite decades of studies. We sequenced the mt genomes of eight species of parasitic lice and compared them with 17 other species of parasitic lice sequenced previously. We found that the typical single-chromosome mt genome is retained in the lice of birds but fragmented into many minichromosomes in the lice of eutherian mammals. The shared derived feature of mt genome fragmentation unites the eutherian mammal lice of Ischnocera (family Trichodectidae) with Anoplura and Rhynchophthirina to the exclusion of the bird lice of Ischnocera (family Philopteridae). The novel clade, namely Mitodivisia, is also supported by phylogenetic analysis of mt genome and cox1 gene sequences. Our results demonstrate, for the first time, that organelle genome fragmentation is informative for resolving controversial high-level phylogenies.

Flies are important arthropod pests in intensive animal facilities such as cattle feedlots, with the potential to cause production loss, transmit disease and cause nuisance to surrounding communities. In the present study, seasonal population dynamics of three important nuisance flies, namely house flies (Musca domestica L.), bush flies (M. vetustissima Walker) and stable flies (Stomoxys calcitrans L.) (Diptera: Muscidae), were monitored on cattle feedlots in south-eastern Queensland, Australia, over 7 years. Musca domestica was by far the dominant species, comprising 67% of the total flies trapped. Models were developed to assess the relationship between weather parameters and fly abundance and to determine whether population trends could be predicted to improve the timing of control measures. For all three species, there were two main effects, namely time-of-year (mainly reflected by minimum temperatures and solar radiation) and rainfall. The abundance of all three species increased with increasing temperature and rainfall, reaching a peak in summer, before decreasing again. Rainfall events resulted in significantly elevated numbers of M. domestica for up to 5 weeks, and for 1 week for M. vetustissima. Peak fly numbers were predicted by the model to occur in spring and summer, following 85–90-mm weekly rainfall. The population dynamics of S. calcitrans were least influenced by rainfall and it was concluded that weather variables were of limited use for forecasting stable fly numbers in this environment and production system. The models provide a useful tool for optimising the timing of fly-control measures, such as insecticide or biopesticide applications, adding to the efficiency of integrated control programs.

OBJECTIVE:To determine the prophylactic and therapeutic efficacy of Australian-registered insecticide formulations against Old World screwworm (OWS) myiases for potential use in screwworm containment and eradication programs.METHODS:The longevity of protection provided by six insecticidal formulations (subcutaneous ivermectin, doramectin and abamectin, a topically applied aqueous formulation of spinosad, ivermectin controlled-release capsule and a dicyclanil spray-on formulation) was tested using implants of 1st-instar OWS larvae on Javanese thin-tail sheep. Therapeutic efficacy of four formulations (topical ivermectin, chlorfenvinphos/cypermethrin mixture, aerosol spinosad formulation and a formulation containing propetamphos and eucalyptus oil) was tested against 2- and 4-day-old OWS strikes.RESULTS:Both the ivermectin capsule and dicyclanil spray-on formulation gave 100% protection against screwworm implants for the full 12 weeks of the study. Ivermectin, doramectin and abamectin administered SC all gave 100% protection at 3 days post-treatment, but at 2 weeks the protection had become incomplete. Spinosad dipping did not give complete protection at any time. All four therapeutic treatments gave complete resolution of 2-day-old strikes and topical ivermectin, spinosad and chlorfenvinphos/cypermethrin, but not the propetamphos/eucalyptus oil formulation, gave complete resolution of all 4-day-old strikes.CONCLUSION:Dicyclanil spray-on and ivermectin capsule formulations, both registered for use in sheep, but not for cattle or other livestock species, gave much longer protection against screwworm implants than the currently recommended SC ivermectin. Pre-emptive action to facilitate rapid deployment of these formulations in the event of a screwworm incursion is urgently needed.

The vectorial and dispersal capacities of flies make them a biosecurity and food safety risk on egg farms. The design of optimal control and biosecurity programs requires knowledge of species composition and patterns of abundance of the fly populations present. Although there have been many studies of flies breeding on egg farms in other countries there is little information available in Australia. We monitored numbers and species of flies breeding on cage egg farms in southern Australia and used mass marking with fluorescent resin dye to assess the dispersal of the major species from one of the farms. The main peak in fly numbers occurred in spring and early summer and was comprised predominantly of little house flies (Fannia canicularis). Significant numbers of false stable flies (Muscina stabulans) were trapped near accumulated manure, but relatively low numbers were present in bird housing areas. House flies (Musca domestica) were found in only low numbers or were absent at most times of the year. In the dispersal studies, 85% of marked F. canicularis and 67% of marked M. stabulans were trapped within 255 m of the layer sheds. The greatest distance from the farm at which marked F. canicularis flies were captured was 739 m for traps and 1.25 km for tapes whereas M. stabulans flies were trapped at all distances including in the most distant trap nearly 2 km from the farm. Modelling of trap catches by distance predicted maximum dispersal distances of 1.6 km for F. canicularis and 2.4 km for M. stabulans.

Rhipicephalus australis (formerly Boophilus microplus) is a one host tick responsible for major economic loss in tropical and subtropical cattle production enterprises. Control is largely dependent on the application of acaricides but resistance has developed to most currently registered chemical groups. Repellent compounds that prevent initial attachment of tick larvae offer a potential alternative to control with chemical toxicants. The repellent effects of Melaleuca alternifolia oil (TTO) emulsions and two β-cyclodextrin complex formulations, a slow release form (SR) and a modified faster release form (FR), were examined in a series of laboratory studies. Emulsions containing 4% and 5% TTO applied to cattle hair in laboratory studies completely repelled ascending tick larvae for 24h whereas 2% and 3% formulations provided 80% protection. At 48h, 5% TTO provided 78% repellency but lower concentrations repelled less than 60% of larvae. In a study conducted over 15 days, 3% TTO emulsion applied to cattle hair provided close to 100% repellency for 2 days, but then protection fell to 23% by day 15. The FR formulation gave significantly greater repellency than the emulsion and the SR formulation from day 3 until the end of the study (P<0.05), providing almost complete repellency at day 3 (99.5%), then decreasing over the period of the study to 49% repellency at day 15. Proof of concept is established for the use of appropriately designed controlled-release formulations to extend the period of repellency provided by TTO against R. australis larvae.