Viticulture is an activity of economic importance in the state of Rio Grande do Sul, especially in Serra Gaúcha, which is the major grape-producing region. However, an increase in cultivated areas has been observed in other municipalities in the state. The aim of this study is to characterize mite diversity and community behavior on different varieties, recognizing which predatory species have potential to control phytophagous mites associated with Europan varieties in the Taquari Valley, Rio Grande do Sul state. The study was conducted in vineyards located in the municipalities of Marques de Souza: ‘BRS Vitória’ and cv ‘Itália’ “m”; Imigrante: cv ‘Itália’ “i”; Dois Lajeados: cv ‘Itália’ (c and f), ‘Tannat’ and ‘Chardonnay’; and Putinga: ‘Champanhe’ and ‘Moscato’. Samplings were carried out monthly in the period ranging from March 2017 to March 2018, during which twenty plants were randomly collected from each variety. Three leaves were clipped from each plant; one from the apical third, one from the median third, and one from the basal third, totaling 60 leaves per area. A total of 10,533 specimens were collected, belonging to 12 families, 38 genera, and 53 species, along with those belonging to the suborder Oribatida. The ‘Itália’ “c” variety had the highest abundance (2,012), followed by ‘Moscato’ (1,788) and ‘BRS Vitória’ (1,593). Phytoseiidae had the highest diversity among the mite families observed, with 20 species followed by Tetranychidae (8). The most abundant species were Polyphagotarsonemus latus (Banks) (3,420) and Euseius concordis (Chant) (565), present throughout the study period. ‘Chardonnay’ variety had the highest similarity (72.55%) among mite fauna compositions and the highest dissimilarity occurred between ‘BRS Vitória’ and ‘Champanhe’ varieties (95.48%). Environments evaluated in Dois Lajeados and Putinga were the most homogeneous concerning mite fauna diversity and abundance.
The production of apples (Malus domestica: Rosaceae) in Brazil is concentrated in three states in the southern region of the country. This crop is of great economic importance for the region, and is usually susceptible to infestations of mite populations. However, recent surveys of mite species associated to apples are scarce. The aim of the present study was to fill this void by analyzing species abundance and composition on three apple cultivars in the southern region of Brazil. The survey was carried out in the states of Rio Grande do Sul (RS), Santa Catarina (SC), and Paraná (PR). A total of 94 apple orchards were evaluated (43 Gala, 40 Fuji and 11 Eva), in 19 municipalities. Twenty plants were sampled from each orchard in March 2019, with four leaves collected from each plant, thus totaling 80 leaves/orchard. Mites were screened and identified in the Laboratório de Acarologia of Universidade do Vale do Taquari - UNIVATES. Data were analyzed using the R software with mixed generalized linear models, non-metric multidimensional scaling, and PERMANOVA. A total of 4,909 mite specimens were identified, belonging to eight species and six genera, of which 1,833 were classified as phytophagous, 1,758 as predators, and 1,318 as generalists. The most abundant phytophagous species was Aculus schlechtendali (33.55%), followed by the predator Neoseiulus californicus (33.14%) and by the generalist Tarsonemus (Tarsonemus) sp. (23.99%). Abundance was similar between Eva and Fuji cultivars. However, these cultivars differed in composition, as did Eva and Gala. The mean number of mites found in Santa Catarina and Rio Grande do Sul was similar, although Paraná had a higher number. Species composition also differed among the three states evaluated. Considering the importance of the apple production in the southern region of Brazil, studies on species composition and abundance are important, aiming to monitor potential damage-causing organisms to the crop and associated predators.
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.
Four new species of eriophyoid mites (Acari: Trombidiformes: Eriophyoidea) were collected from native plant species from Pampa biome, in the state of Rio Grande do Sul, Brazil, and are described and illustrated herein. They have been named: Aculus pampae sp. nov. on Elephantopus mollis Kunth (Asteraceae); Costarectus lanceatus sp. nov. on Sebastiania brasiliensis Spreng. (Euphorbiaceae); Dichopelmus sigfeminae sp. nov. and Rhynacus symflori sp. nov. both on Symplocos uniflora (Pohl) Benth. (Symplocaceae). All new species appeared to be vagrants and no apparent symptom was associated to them.
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