No abstract

Panonychus ulmi is widely distributed in apple and vineyards worldwide. In Brazil, the first damages were observed in apple orchard and later in grapevine. The aim of this study was to evaluate feeding preference and biological traits of P. ulmi on different grapevine varieties (BRS Vitória, Merlot and Concord) and apple (Fuji) under laboratory conditions. The food preference experiment did not reveal any significant differences, but P. ulmi presented the lowest rate of oviposition in the Concord varietal, demonstrating an oviposition preference in V. vinifera varietals and general preference for apple. Mortality was significantly different between varieties, with the lowest mortality on apple and higher oviposition rate in this host. Higher viability occurred on Merlot and apple. Feeding preference studies are scarce, considering phytophagous mites and grape varieties, although they are important in the development of pest control strategies.

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.

Phytophagous mites can cause economic losses in many crops, including grapevines. The changes in their population levels may be associated with changes in the predator-prey relationship. Knowledge of the distribution of mites in plants is important for planning sampling strategies and facilitating control decisions. The aims of this study were to (i) evaluate the abundances of Tetranychus urticae (Tetranychidae) and Neoseiulus californicus (Phytoseiidae), and the correlations between them and environmental factors; (ii) determine their distribution on the top, middle, or base strata of the evaluated grapevines (Vitis vinifera, Chardonnay cultivar) and, additionally, report the first occurrence of damage caused by T. urticae in grapevine leaves in the state of Rio Grande do Sul, Southern Brazil. Sixteen samplings were conducted, divided between the 2018 and 2019 seasons. In each sampling, three leaves from the three strata of the plant (top, middle, and base) were collected from 20 plants, totaling 60 leaves per sampling. The predator-prey relationship and their association with environmental variables were evaluated with multivariate correlation, whereas the number of mites per plant leaf strata was compared using a generalized linear mixed model in R software. It was possible to observe the symptoms of damage caused by T. urticae attacks on grapevines in Southern Brazil, characterized by the presence of yellow spots and general yellowing of the vineyard. Our findings indicate that T. urticae and N. californicus individuals are strongly associated with each other regardless of the environmental variables, and such relationship occurs mainly on the lower strata (middle and base leaves) of grapevines. Thus, by taking into account the damage on the leaves of grapevines and the occurrence of T. urticae and N. californicus majorities on specific strata of these vineyards, we suggest that the lower strata of grapevines should be the priority targets for management strategies to control such mites.

Phytoseiids are important biological control agents on different cultivated plants. This work aimed to know the diversity of phytoseiids and compare the abundance and richness of these mites found in grape-producing regions located in northern Portugal. Samplings were conducted in the subregions of Ave, Cávado, Douro, Lima and Minho Rivers between July and September 2017, in 25 vineyards (three in Ave, four in Cávado, eight in Douro, five in Lima and five in Minho Rivers), by collecting 50 leaves/vineyard. A total of 4,372 phytoseiid mites were found, and the highest abundance of phytoseiids per leaf was in Lima, with an average of 6.4, followed by Douro and Minho, with 2.5 and Ave, with 2.0. The highest richness was found in Ave and Douro, with 80% of the species reported. Typhlodromus pyri predominated in nearly all rivers, except when comparing Ave versus Douro, Cávado versus Douro and, Cávado versus Minho; in these cases, Kampimodromus aberrans predominated in Douro and Minho. This also occurred when K. aberrans and Typhlodromus exhilaratus were compared between Douro and Minho. Comparing Ave and Minho, T. exhilaratus predominated in Minho. Knowing about the phytoseiids present in the studied regions of northern Portugal helps develop biological control strategies and balance these agroecosystems.