Um dos maiores desafios enfrentados pelas presentes e futuras gerações é encontrar formas de preservação das fontes de água, livres de contaminações e adequadas ao consumo da população. Essa dificuldade está relacionada à contaminação dos lençóis freáticos devido à ocupação e uso do solo pela sociedade, alterando os processos físicos, químicos e biológicos dos sistemas naturais, causando inúmeras doenças e muitas vezes levando a morte. O presente trabalho objetivou avaliar a qualidade da água das principais fontes naturais do município de Imigrante, localizado no Vale do Taquari-RS a fim de averiguar a potabilidade das águas consumidas pelas comunidades do município. Na presente pesquisa foram selecionados dez poços para a verificação das características físico-químicas e biológicas, tais como: pH, condutividade, sólidos suspensos, turbidez, oxigênio dissolvido, carbono orgânico, carbono total, carbono inorgânico, nitrogênio, dureza média, temperatura, condutividade e análise microbiológica, comparando os resultados com os padrões preestabelecidos pela legislação vigente. Dos dez poços analisados, seis apresentaram-se fora dos parâmetros estabelecidos pela legislação. Este é o caso dos níveis de turbidez, colorimetria, sólidos totais, nitrato, Coliformes totais e Escherichia coli, parâmetros que em excesso tornam imprópria a água para o consumo com efeitos sobre sua palatabilidade, conferindo propriedades laxantes e mesmo, indiretamente, indicar a presença de patógenos que podem ter graves repercussões sobre a saúde. Assim, este estudo destaca a necessidade de utilizar os métodos de desinfecção de água de poços antes de seu consumo.
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.
ResumoBiologia de Neoseiulus californicus alimentando-se de ácaro rajado. Tetranychus urticae (Koch) destaca-se por ser um ácaro polífago. Em morangueiro, esse ácaro desenvolve-se na face inferior das folhas, causando lesão significativa. Este estudo teve por objetivo conhecer as características biológicas de Neoseiulus californicus (McGregor), proveniente de plantas de morangueiro cultivado. O estudo iniciou-se com trinta ovos individualizados em arenas com diferentes estágios de T. urticae como alimento. A duração média de ovo-adulto foi maior para fêmeas (5,69±0.08) do que para machos (5,35±0.11). A razão sexual foi de 0,66 e capacidade inata de aumento (rm) foi de 0,15 fêmea/fêmea/dia. A taxa líquida de reprodução (R o ) foi 17,10 vezes/geração, com uma média a cada geração (T) de 19,35 dias. Maior oviposição foi observada no 11º dia após o seu início, com 2,7 ovos/fêmea/dia e a média foi de 38,14±5,58 ovos/fêmea. A razão finita de aumento (λ) foi 1,41 fêmea/ dia. Neoseiulus californicus mostrou reproduzir-se adequadamente quando alimentado com T. urticae. Palavras-chave: Controle biológico; Fragaria sp.; Inimigo natural; Tabela de vida; Tetranychus urticae AbstractTetranychus urticae (Koch) stands out as a polyphagous mite. In a strawberry plant, this mite develops on the underside of leaves, causing a significant injury. This study aimed to know the biological characteristics of Neoseiulus californicus (McGregor), from cultivated strawberry plants. The study started with thirty eggs isolated in arenas with different stages of T. urticae. The average length of egg-adult was higher for females (5.69±0.08) than for males (5.35±0.11). The sex ratio was 0.66 and the innate capacity for increase (rm) was 0.15 female/ female/day. The net reproductive rate (R o ) was 17.10 times/generation, with an average to each generation (T) of 19.35 days. Greater oviposition was observed at the 11 th day after its onset, with 2.7 eggs/female/day and the average was 38.14±5.58 eggs/female. The finite increase rate (λ) was 1.41 female/day. Neoseiulus californicus showed to reproduce properly when feeding on T. urticae.
This study evaluated the biological characteristics of predatory mite Cheyletus malaccensis fed on Dermanyssus gallinae at different temperatures. The study started with thirty individual eggs of C. malaccensis each isolated in an experimental unit, which developed throughout their life stages while feeding on D. gallinae at each temperature tested (20ºC, 25ºC and 30±1ºC and 80±5% relative humidity). Emerged adult females were not mated, thus producing only male offspring (arrhenotoky). Fecundity was the highest at 25°C (415.62±24.78 eggs/female) and lowest at 20°C followed at 30ºC. The mean length of a generation did not displayed difference among the three temperatures, but the net reproductive rate (Ro), innate capacity for increase (rm) finite increase rate (λ) were significantly higher at 30°C and lower at 20°C. Cheyletus malaccensis was able to develop and reproduce successfully when fed D. gallinae, and the optimum temperature for development, fertility and survival was 25°C. Our findings proved that C. malaccensis might be a natural enemy of D. gallinae, because it was able to develop and reproduce while feeding exclusively on this ectoparasite.
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