Osmotin1 is involved in rice resistance to Schizotetranychus oryzae (Acari: Tetranychidae) infestation.

BACKGROUND: Rice is one of the most consumed cereals in the world. Productivity losses are caused by different biotic stresses. One of the most common is the phytophagous mite Schizotetranychus oryzae Rossi de Simons (Acari: Tetranychidae), which inhibits plant development and seed production. The identification of plant defense proteins is important for a better understanding of the mite-plant interaction. We previously detected a high expression of Osmotin1 protein in mite-resistant rice cultivars, under infested conditions, suggesting it could be involved in plant defense against mite attack. We therefore aimed to evaluate the responses of three rice lines overexpressing Osmotin1 (OSM1-OE) and three lines lacking the Osmotin1 gene (osm1-ko) to mite attack. RESULTS: The numbers of individuals (adults, immature stages, and eggs) were significantly lower in OSM1-OE lines than those in wild-type (WT) plants. On the other hand, the osm1-ko lines showed larger numbers of mites per leaf than WT plants. When plants reached the full maturity stage, two out of the three infested OSM1-OE lines presented lower plant height than WT, while the three osm1-ko lines (infested or not) presented higher plant height than WT. The reduction in seed number caused by mite infestation was lower in OSM1-OE lines (12-19%) than in WT plants (34%), while osm1-ko lines presented higher reduction (24-54%) in seed number than WT plants (13%). CONCLUSION: These data suggest that Osmotin1 is involved in rice resistance to S. oryzae infestation. This is the first work showing increased plant resistance to herbivory overexpressing an Osmotin gene. © 2023 Society of Chemical Industry.

Impact of the mites Dermanyssus gallinae and Tyrophagus putrescentiae on production and health of laying hens.

Mites are considered a threat to the commercial poultry industry due to their direct and indirect pathogenic effects. Dermanyssus gallinae is among the mite species that endanger production, as it is hematophagous and poses a serious sanitary risk. Recently, Tyrophagus putrescentiae has also drawn attention as a potential pest in the poultry industry, and its attacks have been related to clinical symptoms such as cutaneous eruptions and bird restlessness. Considering the potential economic, sanitary, and productive losses both species represent to the laying-hen industry, the aim of the present study was to evaluate the influence of D. gallinae and T. putrescentiae on the health and productivity of commercial laying hens by carrying out infestation experiments and by monitoring laying hens for a period of 60 days. Tyrophagus putrescentiae and D. gallinae affected egg quality and zootechnical parameters in laying hens. Hens infested by T. putrescentiae had behavioral changes, weight loss, stress symptoms, and decreased egg laying and quality, as well as diarrhea, gradual feather loss, and itching. Hens infested by D. gallinae also had weight loss, behavioral changes, and stress symptoms, leading to decreased laying and egg quality. The present study proposes an experimental model to understand the impacts caused by T. putrescentiae and D. gallinae on commercial laying production and egg quality parameters.

Acarofauna associated with organic matter in laying aviaries of different rearing systems in Brazil.

Due to the high density of chickens housed within the same space in aviaries, a large volume of organic matter accumulates on the floor. This large supply of available resources allows the development of arthropods, including organisms that affect poultry productivity and health. This study aimed to evaluate the composition of the mite community associated with organic matter in poultry houses with different rearing systems and the verification of potential predators to be evaluated in clean management techniques, such as biological control. The study was carried out in the state of Rio Grande do Sul (Brazil) in a total of six poultry houses, two of the 'Californian' system (SIG) and four of the 'cage free' system (SIF). In total, 839,459 specimens were collected, of which 358,044 were collected from SIF and 481,415 specimens from SIG. Fifty-two species/morphospecies were found and we observed a grouping of aviaries from the same rearing model. Species of medical veterinary importance were found, such as Dermanyssus gallinae, Megninia ginglymura, Ornithonyssus sylviarum and Tyrophagus putrescentiae. The results demonstrate that the organic matter present in the aviaries harbors a high diversity of mites of medical-veterinary importance and predators, which are influenced by the rearing system.

Effects of in-house and commercial extracts of the allergenic mite Tyrophagus putrescentiae on murine and human cell responses.

Mites are among the major sources of domestic and occupational allergens worldwide, and continuous exposure to these allergens leads to chronic airway inflammation. One of the most allergenic species is the storage mite Tyrophagus putrescentiae (Schrank). Protein extracts are produced from this mite for tests that help the clinical diagnosis (via prick test), treatment, and monitoring of disease progression in patients who had positive results for allergic reactions. Therefore, the aim of the present study was to evaluate the cell viability of RAW 264.7 and L929 cells when exposed to in-house raw protein extracts of T. putrescentiae compared to a commercial product, as well as quantify TNF-α secretion by RAW 264.7. Additionally, this study quantified the effect of these extracts in IgE secretion in total blood of people affected by this mite. The study found similarity between the in-house extract and the commercial extract as they had equivalent TNF-α secretion. Additionally, viabilities of RAW 264.7 and L929 exposed to the in-house extract were compatible with viabilities of cells exposed to the commercial extract, with no cytotoxicity at the concentrations tested. Results corroborated the hypothesis that the extract produced in-house would be equivalent to the commercial extract in allergic patients when the IgE was quantified. This study is the first to show the cytotoxicity of T. putrescentiae extracts, and to provide a quantitative analysis of TNF-α and IgE.

Challenges in the Biological Control of Pests in Poultry Production: a Critical Review of Advances in Brazil.

Poultry farming is an important activity in animal protein production worldwide, either by laying hen farming or broilers. Over the last decades, the change in production systems with confinement of large numbers of hens has increased productivity and reduced costs; however, it has also increased sanitary issues. In this setting, arthropods that are adapted to poultry houses have gained great importance. They cause direct damage to hens, either by blood spoliation caused by ectoparasites or lesions in the digestive tract (e.g., lesser mealworm) or by indirect damages, by transmitting pathogens or by affecting egg quality, when they attain pest status. Synthetic chemical products comprise the most frequently used control strategy against these pests, with relative efficacy and many side effects. In Europe, some countries also adopt alternative prevention or control measures. In Brazil, however, although there are some groups of researchers that work on developing alternative control, its use is virtually zero. The present review shows a critical overview of this context in Brazil, based on the alternatives that have already been studied and made available, but have not been implemented, yet, and the potential stumbling blocks created by the very poultry market against these advances.

Associations between house dust mites and prevalence of asthma and allergic rhinitis among school-age adolescents in the south of Brazil / Associações entre ácaros da poeira domiciliar e prevalência de asma e rinite alérgica em adolescentes em idade escolar no sul do Brasil

Background: Allergic reactions resulting from exposure to environmental allergens are responsible for problems such as asthma and allergic rhinitis. House dust mites (HDMs) are one of the most important causes of allergic sensitization and a major source of allergens worldwide. Objective: To investigate associations between the presence of HDMs in the homes of adolescents aged 13 to 14 years and the prevalence of respiratory problems using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Methods: A total of 103 adolescents from the city of Lajeado, south of Brazil, participated in the ISAAC Protocol, and 10 homes were sampled for dust collection. Results: Regarding the medical history of asthma and rhinitis, a prevalence of 14.7% of asthma was found, and 68.9% of the adolescents have already had rhinitis. The investigation of active asthma and rhinitis showed that 5.15% of adolescents had symptoms of asthma and 39.14% had symptoms of allergic rhinitis. Premature birth, low birth weight and smoking mother were shown to be risk factors for the development of asthma and allergic rhinitis. HDMs were mostly found on the carpet (46.80%), followed by bed (34.04%) and sofa (14.89%); curtains had the fewest mites (4.25%). Dermatophagoides pteronyssinus (46.0%) and Dermatophagoides farinae (31.91%) were the most frequently found species. Conclusion: The homes of adolescents with respiratory problems had a large number of HDMs.

Introdução: As reações alérgicas resultantes da exposição a alérgenos ambientais são responsáveis por problemas como asma e rinite alérgica. Os ácaros conhecidos como ácaros da poeira domiciliar (HDMs) são uma das causas mais importantes de sensibilização alérgica e representam uma das fontes de alérgenos mais importantes do mundo. Objetivo: O presente estudo tenta encontrar uma relação entre a presença de HDMs nas residências de adolescentes de 13 a 14 anos e a prevalência de problemas respiratórios, usando o questionário ISAAC (International Study of Asthma and Allergies in Childhood). Método: Participaram do Protocolo ISAAC 103 adolescentes da cidade de Lajeado (RS), dez domicílios foram amostrados para coleta de poeira. Resultados: Em relação à história clínica de asma e rinite, foi encontrada prevalência de 14,7% de asma, sendo que 68,9% dos adolescentes já apresentaram rinite. A investigação de asma e rinite ativa mostrou que 5,15% dos adolescentes apresentaram sintomas de asma e 39,14% apresentaram sintomas de rinite alérgica. Nascimento prematuro, baixo peso ao nascer e mãe fumante demonstraram ser fatores de risco para o desenvolvimento de asma e rinite alérgica. O local onde foi encontrado o maior número de ácaros foi tapete (46,80%), seguido de cama (34,04%), sofá (14,89%); cortina foi o local com menor número de ácaros encontrados (4,25%). Dermatophagoides pteronyssinus (46,0%) e Dermatophagoides farinae (31,91%) foram as espécies mais encontradas na poeira. Conclusão: As residências de adolescentes com problemas respiratórios apresentaram um maior número de HDMs.

Influence of laying hen-systems and ecologic variables on mites of medical and veterinary importance.

The search for improvements in the poultry production chain and for increased egg productivity have grown significantly. However, intensive production with or by using of confinement systems negatively affect the welfare of animals and is favoring the appearance of harmful ectoparasites in production. Due to differences in the existing management systems, (e.g. Californian and cage-free systems) and given the importance of the poultry industry in the international market, the aim of the present study was: (1) to compare mite community between SIG (Intensive system - cage: Californian) and SIF (Intensive system - free: cage free); (2) egg-laying systems to analyze how the abundances of the ectoparasites Dermanyssus gallinae, Megninia ginlgymura, and Ornithonyssus sylviarum are affected by these egg-laying models; (3) to evaluate the association between the functional diversity found in traps, organic matter, and feathers in both systems; and finally, (4) to analyze how abiotic factors (e.g. humidity, temperature at sampling) affect mite community composition inside each model. A total of 860,571 mites were sampled, belonging to 59 taxa from six functional groups. Mite composition in the SIF system was different from the SIG system, while their variations in dispersion homogeneity were quite similar to each other. Although taxonomic composition is different between them, they are quite similar when clustered according to functional diversity. The variables 'humidity' and 'temperature' were not determining factors for the appearance of species. The species that most contributed for distinguishing the models were: M. ginlgymura, Dermatophagoides farinae, D. gallinae, Tyrophagus putrescentiae, O. sylviarum, Blattisocius keegani, Glycyphagus sp., Acotyledon sp., and Cheyletus malaccensis, respectively. Dermanyssus gallinae was strongly associated with the Californian model. Two taxa were highly correlated with cloaca, neck, dorsum, and inner wings; variations in relative air humidity also affected M. ginlgymura and O. sylviarum populations. Organic matter had a high abundance of predatory mites with potential for controlling mites of sanitary importance in the poultry chain.

In vitro evaluation of the response of Dermanyssus gallinae to products in aqueous suspension.

The hematophagous mite Dermanyssus gallinae poses a serious sanitary problem in the Brazilian laying poultry industry. Its control is typically performed with acaricides, either in powder or liquid form. However, the intensive use of these products has caused populations of this species to develop tolerance and even resistance. The aim of the present study is to evaluate the response of eggs and adults of D. gallinae to products in aqueous suspension according to commercial indication and as per the recommendations of the Brazilian Ministry of Agriculture, Livestock and Supply. The study used four acaricide products (product 1: cypermethrin, chlorpyrifos, and piperonyl butoxide; product 2: alkyl-benzyl-dimethyl ammonium chloride, glutaraldehyde, deltamethrin; product 3: dichlorvos; product 4: fluralaner) tested in vitro using the contact method. Distilled water was used in the control group. The effectiveness of each of the products differed significantly between eggs and adults. Products 2, 3, and 4 caused 100% of adult mortality up to day 5 after start of treatment, product 1 97.5%. The corrected mortality (non-viability) of eggs was 21.4% (product 1) 39.4% (product 2), 47.8% (product 3), and 14.4% (product 4). Although the products evaluated were effective against adults of D. gallinae, their effectiveness against eggs was lower under the same conditions. This finding might be directly related to frequent D. gallinae reinfestations in poultry houses.

Mite fauna on transgenic soybean in an experimental station in western Bahia, Brazil

The aim of this study was to identify mite fauna associated with soybean crops and to report new species of the Monsoy 8349 IPRO variety in the municipality of Luís Eduardo Magalhães, western region of Bahia. Samplings were performed in an area with transgenic soybeans, subdivided into three treatments: T01, with no use of agricultural pesticides; T02, complete package of pesticides, except for acaricides; and T03, complete package of pesticides including acaricides. Twenty plants were selected per treatment at each sampling; one apical, one median, and one basal leaf were collected from each plant, totaling 60 leaves per treatment. A total of 1,292 mites were found, belonging to three families, five genera, and six species. The major phytophagous mite species found were Mononychellus planki McGregor and Tetranychus urticae Koch, while the major predatory mites found were Neoseiulus transversus Denmark & Muma and Euseius concordis Chant.

Evaluation of the activity of filamentous fungi isolated from soils of the Pampa biome applied in the biological control of Tetranychus urticae (Acari: Tetranychidae) and Polyphagotarsonemus latus (Acari: Tarsonemidae).

Tetranychus urticae Koch and Polyphagotarsonemus latus Banks are mite species considered capable of attaining pest levels, damaging a range of agricultural crops. The Pampa biome is characterized by the high biodiversity it houses, particularly microbial diversity, which highlights its potential for developing microorganisms that can provide biological control of arthropods. The aim of this study was to evaluate the activity of four fungal isolates from the soil of the Pampa biome in the biological control of T. urticae (females and eggs) and P. latus (females). Experiments consisted of isolating and identifying fungal isolates for spore quantification and aspersion at 108, 106, and 104 spores/mL concentrations in arenas containing T. urticae females and eggs, and P. latus females, separately. Results indicated that only three isolates (Aspergillus brunneoviolaceus, Clonostachys chloroleuca, and Penicillium adametzii) showed high control of T. urticae females, yet they did not exhibit any control of T. urticae eggs and P. latus females. Therefore, the present study confirms the viability of some of these fungi as biological control agents of mites, which implies the importance of new prospects with other fungal species, considering the richness of resources in the Pampa biome, or even the need to test higher concentrations and other variables using the microorganisms of the present study.

Case report: Tyrophagus putrescentiae (Acari) attacking laying birds in conventional poultry houses.

Tyrophagus putrescentiae (Schrank) (Acaridae) is one of the most allergenic mite species worldwide, and it particularly infests household environments, animal feed factories, and food factories. It has been the aim of several studies recently in the healthcare area due to its allergenic potential. However, there had been no records of this species attacking laying birds until this report. This is the first record of adverse reactions in animals triggered by infestations of this species. Therefore, the present study aims at describing the damages and symptomatology of T. putrescentiae infestations on commercial laying hens. Alopecia and dermatitis were symptoms exacerbated by T. putrescentiae infestation starting at 40 weeks old. The presence of this species on hens, as observed in the present study, might be directly related to the accumulation of food and poultry litter on these birds, in their cages, or in the vicinities. Hence, the results might be related to their feeding behavior, which consists of continuous supply of animal feed in these management systems. The present study provides an unprecedented record that reveals the importance and potential for emergency pest status of T. putrescentiae in the poultry industry. Its infestations in poultry houses probably required constant sanitary care and monitoring are required in order to prevent outbreaks of this mite.

New species of predatory mites (Acari: Prostigmata: Cunaxidae) for southern Brazil.

Two new species of Cunaxidae, Cunaxoides lajeadensis Wurlitzer Monjarás-Barrera sp. nov. and Lupaeus waldumirus Wurlitzer Monjarás-Barrera sp. nov., are described from Ipomoea alba L. (Convolvulaceae) on the edge of an urban forest fragment.

Population growth of the stored product pest Tyrophagus putrescentiae (Acari: Acaridae) on environmentally and medically important fungi.

The stored food mite Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) has been associated with the presence of several fungal species. The aims of this work were to evaluate T. putrescentiae population growth associated to environmental and medically important fungal species to determine on which fungal species populations of T. putrescentiae performs best, and to evaluate their ability to disperse each fungal species. First, 24 fungal species were inoculated separately in Petri dishes containing Sabouraud agar medium. One week after inoculation, 50 mites were added to each plate. On the 28th evaluation day, mites and eggs were counted in each plate, and 50 mites randomly collected from each replicate were transferred to new plates containing only Sabouraud agar medium. Then, mites, eggs, and fungal population were evaluated in each plate on day 28 again. The highest population increases were on Trichophyton mentagrophytes, Alternaria sp., Microsporum gypseum, and Aspergillus chevalieri. With Fusarium guttiforme and the medically important fungi Microsporum canis, M. gypseum, T. mentagrophytes, and Sporothrix sp., mites were observed to feed on whole mycelium. Only eight fungal species were dispersed by T. putrescentiae to the new Petri dishes: Aspergillus clavatus, Candida tropicalis, Candida albicans, Fusarium guttiforme, Hyphopichia burtonii, Penicillium citrinum, Rhizophus azygosporus, and Trichophyton mentagrophytes. The best performance of T. putrescentiae was found feeding on F. guttiforme, P. citrinum, and T. mentagrophytes. In conclusion, T. putrescentiae successfully used fungi as a food source, and it proved to be an important tool for disseminating both environmental and medically important fungi.

Stigmaeid mites (Acari: Stigmaeidae) from vineyards in the state of Rio Grande do Sul, Brazil.

The fauna of the family Stigmaeidae Oudemans on grapevines and weed plants associated with vineyard agroecosystem in the state of Rio Grande do Sul (Brazil) was studied. Five recognized species were reported: Agistemus brasiliensis Matioli et al., 2002, Agistemus floridanus Gonzales, 1965, Agistemus mendozensis Simons, 1967, Zetzellia agistzellia Hernandes and Feres, 2005, and Zetzellia malvinae Matioli et al., 2002. Two new species were described: Agistemus riograndensis sp. nov. and Zetzellia ampelae sp. nov. A pictorial key was compiled to aid in the recognition of these stigmaeids.