Bioecologia de ácaros da cultura da soja e influência da transgenia

As cultivares geneticamente modificadas alteram o manejo da cultura da soja (Glycine max L. Merril: Fabaceae). O aumento no uso de agroquímicos decorrentes do plantio de transgênicos é exemplo de prática que coloca em cheque o futuro dos solos e biodiversidade. Dentre as espécies de ácaros fitófagos que causam danos à cultura destacam-se Mononychellus planki McGregor e Tetranychus ludeni Zacher. O Caliothrips phaseoli Hood (Thysanoptera: Thripidae) também pode atingir nível de praga nestas plantações. Estes ácaros e inseto se alimentam das folhas da soja causando clorose e perda na produção de grãos. Neoseiulus californicus McGregor (Acari: Phytoseiidae) é utilizado no controle de populações de ácaros praga em culturas agrícolas, porém não são conhecidos seus parâmetros biológicos quando alimentados com M. planki e C. phaseoli. O objetivo deste trabalho foi conhecer os parâmetros biológicos de N. californicus quando alimentado de M. planki, T. ludeni e C. phaseoli sobre folhas de soja nas condições de laboratório e avaliar a influência da transgenia sobre o ciclo biológico de T. ludeni. Os ácaros foram coletados em plantações de soja da cidade de Lajeado - RS. No estudo com o predador foram utilizados ovos individualizados em arenas com M. planki, T. ludeni e C. phaseoli como alimento. Foram realizados estudos observando o desenvolvimento e reprodução de T. ludeni sobre soja convencional Fundacef 44, RR Nideira 5909, resistente ao glifosato e BT Rota 54, resistente ao glifosato e ao ataque de lagartas. A viabilidade total de ovo-adulto para o predador se alimentando de T. ludeni, M. planki e C. phaseoli foram 96.66%, 76.67% e 53.33%, respectivamente. O predador não completou seu desenvolvimento sendo alimentado com C. phaseoli, pois não houve oviposição. A capacidade de aumentar em número (rm) foi de 14.46 fêmeas/fêmeas/dias com T. ludeni e 13.39 com M. Planki. A transgenia na soja não demonstrou interferir na biologia de T. ludeni. Esta espécie pode estar em fase de adaptação à cultura, pois teve parâmetros de reprodução menores que o esperado. Os resultados poderão subsidiar trabalhos de controle biológico na soja e outras culturas que apresentarem as mesmas espécies herbívoras em nível de praga. Também contribuir para as discussões acerca do uso de transgênicos.The genetically modified cultivars change management culture of soybean, Glycine max L. Merri: Fabaceae. The dramatic increase in the use of agrochemicals arising from the planting of GM crops is practical example that puts in check the future of soil and agricultural biodiversity. Among the species of phytophagous mites that cause damage to culture, include Mononychellus planki McGregor, Tetranychus ludeni Zacher and Tetranychus urticae Koch. Caliothrips phaseoli Hood (Thysanoptera: Thripidae) is a species of insect that can also reach plague level in these plantations. The species lay their eggs on the leaves of soybeans and feed her causing chlorosis and loss in grain production. Neoseiulus californicus McGregor is already used in the control of pest mites in different cultures, but are not known their biological parameters feeding on M. planki and C. phaseoli. The aim of this study was to evaluate the biological parameters of N. californicus feeding on M. planki, T. ludeni and C. phaseoli in soybean leaves and the influence of transgenic on an herbivore, T. ludeni. The mites were collected in soy plantations in the city of Lajeado-RS. In the study with the predator, individualized eggs were used in arenas with M. planki, T. ludeni and C. phaseoli as food. Noted the development and reproduction of t. ludeni in different soybean cultivars, these being, conventional soybeans Fundacef 44, and of two types of genetically modified soybeans, RR Nideira 5909 glyphosate resistance e BT Rota 54 glyphosate resistant and the attack of caterpillar. The total egg viability-adult for the predator feeding on T. ludeni, M. planki and C. phaseoli was 96.66% respectively, 76.67% and 53.33%. The predator has not completed its development being fed with C. phaseoli, do you ovipositou. The ability to increase in number (rm) was 14.46 with T. ludeni and 13.39 female/female/day with M. planki. The varieties in soybeans has not shown to interfere with the biology of T. ludeni. Is species may be in the process of adaptation to the culture, as it had playback parameters smaller than expected. The results may subsidize works of biological control in soybeans and other crops which submit same herbivore species pest level. Also, contribute to discussions about the use of transgenic crops.CAPE

Mite fauna associated with different environments of Brazilian Pampa and a case of predatory mite impairing the control of invasive plant

The Brazilian Pampa is predominantly a natural pasture region with gallery forest formations. It conserves a rich biodiversity and provides vast biological resources for economic use. Pampa suffers from the replacement of fields by grain crops and tree planting to obtain cellulose. The objectives of this work were to evaluate the composition of the mites community comparing the different environments; to relate mite fauna to microclimatic factors and to know the interactions between mites/plants; description of new species and evaluate the biology of Euseius stipulatus (Athias-Henriot) and Typhlodromus (Typhlodromus) exhilaratus Ragusa feeding on Aculus mosoniensis Ripka (Eriophyidae) from an invasive plant Ailanthus altissima (Mill.) Swingle (Simaroubaceae). Mites were collected from the most representative plant species in the Grassland, Grazing Exclusions and Riparian Forest environments of Pampa biome. To evaluate the diversity of mites between enviroments, the ANOSIM test was used at a significance level of 5%. Four new species of eriophyoid mites were described and illustrated. Regarding the predators Phytoseiidae and Stigmaeidae, the Riparian Forest environment had the highest abundance (72%), followed by Grazing Exclusions (20%) and Pastures (8%). One hundred seventeen species of mites were collected in the three environments, being the majority phytophagous (57%). The Riparian Forest environment forms an independent grouping from Grazing Exclusions and Grassland. The species responsible for the similarity of the Grassland and Grazing Exclusions environments was Tydeus californicus (Banks), while to the Riparian Forest, Brachytydeus formosa (Cooreman) was the most significant. Air humidity and soil correlated with Riparian Forest indicators, while active photosynthetic effects, temperature and higher wind velocity correlated with Grassland and Grazing Exclusions. Euseius stipulatus may make hinder the biological control of invasive plant A. altissima. The three environments presented mite species with a high number of plant interactions, greater than ten. Mites were indicators responding to environmental differences evaluated Grassland, Grazing Exclusions and Riparian Forest.Cape

Por que preservar os campos do extremo sul do Brasil?

In Brazil, grassland ecosystems of the Pampa are restricted to Rio Grande do Sul State (RS) and constitute the largest temperate natural grassland in the world. There are no recent data to indicate how much of these fields was lost in the state, but excursions made in recent years have pointed to a high conversion of native fields into crops. This situation has alerted to the intensification of biodiversity loss and the biological impoverishment of these fields. In view of the above, this study characterizes plant diversity in fields of the southern and western portion of RS. The study was based on publications of recent years that indicate the problems that effectively threaten this diversity. Pampa fields are natural and have a great diversity, constituting a considerable genetic heritage, ensuring the provision of ecosystem services to human populations. The few bioprospecting studies on species from these fields suggest that much remains to be discovered and that actions need to be taken to inhibit field destruction. These fields have never been treated as priority areas for conservation, but it is our commitment to reverse this transformation and destruction.No Brasil, os ecossistemas campestres do Pampa estão restritos ao Rio Grande do Sul (RS) e constituem a maior área de pastagem natural de clima temperado do mundo. Não existem dados recentes que indiquem o quanto se perdeu desses campos no RS, mas excursões realizadas nos últimos anos têm possibilitado a percepção de que é alta a conversão dessas áreas nativas em lavouras. Tal situação tem alertado para a intensificação da perda da diversidade e do empobrecimento biológico desses campos. Diante disso, o estudo objetivou caracterizar a diversidade vegetal dos campos da metade sul e oeste do RS, baseado em publicações dos últimos anos. Os campos pampeanos são naturais, com grande biodiversidade, constituindo um considerável patrimônio genético, garantindo a prestação de serviços ecossistêmicos para as populações humanas. Os poucos estudos de bioprospecção com espécies desses campos sugerem que muito ainda pode ser descoberto e que é preciso implantar ações para inibir a destruição dos mesmos. Esses campos nunca foram tratados como áreas prioritárias para a conservação, no entanto, é nosso compromisso reverter esse quadro de transformação e destruição

Análise da Qualidade da Água de Poços Artesianos do Município de Imigrante, Vale do Taquari/RS

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

Biology of Neoseiulus californicus feeding on two-spotted spider mite

http://dx.doi.org/10.5007/2175-7925.2013v26n2p105 Tetranychus 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 (Ro) was 17.10 times/generation, with an average to each generation (T) of 19.35 days. Greater oviposition was observed at the 11th 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

Biology of Neoseiulus californicus feeding on two-spotted spider mite

Tetranychus 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 (Ro) was 17.10 times/generation, with an average to each generation (T) of 19.35 days. Greater oviposition was observed at the 11th 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

The effect of temperature on the biology of Phytoseiulus macropilis (Banks) (Phytoseiidae) in applied biological control program

Phytoseiulus macropilis (Banks) (Phytoseiidae) is a natural enemy of Tetranychus urticae Koch (TSSM), a common pest in several cultures, especially in greenhouses. This research aimed to know the biological parameters of a strain of P. macropilis from Vale do Taquari, State of Rio Grande do Sul, feeding on TSSM at different temperatures. The study was initiated with 30 eggs individualized in arenas under the temperature of 20, 25 and 30 ± 1°C and relative humidity of 80 ± 10%. The average length (T) of each generation decreased with the increase of temperature, ranging from 25.71 days at 20°C to 11.14 days at 30°C. The net reproductive rate (Ro) ranged from 45.47 at 20°C to 18.25 at 30°C; the innate capacity for increase (rm) was 0.15 at 20°C, reaching 0.26 at 30°C and the finite increase rate (λ) ranged from 1.41 to 1.82 females day-1 at 20 and 30°C, respectively. In the present study, it was observed that the strain of the evaluated predatory mite from mild climate of South Brazil, might present a good performance to control TSSM when exposed to a temperature range between 20 and 30°C.

Mite fauna (Acari) associated to commercial laying hens and bird nests in Vale do Taquari, Rio Grande do Sul, Brazil

The control of ectoparasites is essential for maintaining biosafety in a poultry farm. This paper aimed to analyze the mite fauna associated to abandoned nests and commercial laying hens in the towns of Lajeado and Teutônia, Vale do Taquari, Rio Grande do Sul, Brazil. Samplings were conducted from December 2010 to July 2011. A total of 11,757 mites belonging to 21 families and 31 species were found. Cheyletidae showed the highest number of species (4), followed by Blattisocidae (3 species). Dermanyssus gallinae (De Geer) showed the highest number of individuals (5,689), followed by Megninia gynglimura Mégnin (2,175), and Chortoglyphus arcuatus Troupeau (1,488). Blattisocius tarsalis Berlese, C. arcuatus, and D. gallinae were found on traps, feathers, poultry farm nests without cages (free), and abandoned bird nests

Could phytoseiid mites impair biological control of the invasive plant, Ailanthus altissima?

Aculus taihangensis is a potential biological control agent of Ailanthus altissima (Miller) Swingle. However, predatory mites found in Europe may affect the action of this eriophyid agent. The aim of the present study was to evaluate the biology of two predatory mites, Euseius stipulatus and Typhlodromus (Typhlodromus) exhilaratus, feeding on A. taihangensis. Rearing stocks were maintained in germination chambers at 25 +/- 1 degrees C, with 12 hours of photophase and relative humidity 70 +/- 5%. Of 40 individualized T. (T.) exhilaratus eggs, only 37.5% achieved adulthood, while viability of E. stipulatus was 87.5%. The mean fecundity was 18 eggs/ female. Both predatory mites evaluated in this study feed on A. taihangensis. However, only E. stipulatus seems to be an efficient predator, capable of controlling A. taihangensis

Communities of predatory mites (Phytoseiidae and Stigmaeidae) in different environments of the Brazilian Pampa

Toldi, Maicon, Freitas, Elisete Maria de, Silva, Vinícius Leão da, Caumo, Monique, Ferla, Júlia Jantsch, Orlandi, Carla Roberta, Da-Costa, Tairis, Johann, Liana, Ferla, Noeli Juarez (2021): Communities of predatory mites (Phytoseiidae and Stigmaeidae) in different environments of the Brazilian Pampa. Acarologia 61 (1): 20-30, DOI: 10.24349/acarologia/20214413, URL: http://dx.doi.org/10.24349/acarologia/2021441