The use of rhizobium and mycorrhizae in soil containing rhizobiophage to improve growth and nodulation of cowpea

The interaction between leguminous plants and rhizosphere microorganisms is essential because it can either enhance or inhibit the beneficial effects of individual species. Phages are one of the biotic factors with a negative impact on the beneficial bacteria in soil rhizosphere. In the current study, phage showed lytic activity against Bradyrhizobium sp. Vigna (tal16) with an icosahedral head at a 43.44 nm diameter and a long non-contractile tail, measuring 99.85 nm. This phage belongs to the Siphoviridae family, found in the Met El-Ez area of Dakalia Governorate in Egypt. The results revealed that the presence of phage in soil affected nodulation and growth parameters. Mycorrhizal inoculation aggravated the negative effects of this phage. Cowpea grown in soil containing phage VB_BrV_SD4 showed a reduction in the nodule number, nitrogenase activity, and total N of 40-50 %; however, mycorrhizal inoculation augmented this negative effect with a reduction percentage to 20-28 %. Mycorrhizal inoculation also improved total chlorophyll, carotenoids, legume amount, and the seed protein content.

Distribution of gall-inducing arthropods in areas of deciduous seasonal forest of Parque da Sapucaia (Montes Claros, MG, Brazil): effects of anthropization, vegetation structure and seasonality

In the present study, we inventoried gall-inducing arthropod species and evaluated the effects of habitat anthropization, vegetation structure and seasonality on this group in areas of deciduous seasonal forest of Parque da Sapucaia, Montes Claros, MG, Brazil. The gall-inducing fauna was sampled between April 2017 and February 2018 from 20 plots distributed in anthropized and preserved habitats. A total of 29 morphospecies of gall-inducing arthropods and 21 species of host plants were recorded. The Fabaceae plant family had the highest number of gall morphospecies (n = 10), while the Cecidomyiidae (Diptera) insect family induced the most galls (41.3%). Mean gall richness did not differ between preserved and anthropized plots, but was negatively affected by mean vegetation height and density. The total number of gall morphospecies recorded during each sampling did not differ between dry and rainy seasons, but the mean richness of galls per plot was higher in the rainy season. In conclusion, natural factors, such as vegetation structure and seasonality, were more important for the distribution of gall-inducing species than anthropic factors, such as vegetation anthropization level.

Distribution of gall-inducing arthropods in areas of deciduous seasonal forest of Parque da Sapucaia (Montes Claros, MG, Brazil): effects of anthropization, vegetation structure and seasonality

In the present study, we inventoried gall-inducing arthropod species and evaluated the effects of habitat anthropization, vegetation structure and seasonality on this group in areas of deciduous seasonal forest of Parque da Sapucaia, Montes Claros, MG, Brazil. The gall-inducing fauna was sampled between April 2017 and February 2018 from 20 plots distributed in anthropized and preserved habitats. A total of 29 morphospecies of gall-inducing arthropods and 21 species of host plants were recorded. The Fabaceae plant family had the highest number of gall morphospecies (n = 10), while the Cecidomyiidae (Diptera) insect family induced the most galls (41.3%). Mean gall richness did not differ between preserved and anthropized plots, but was negatively affected by mean vegetation height and density. The total number of gall morphospecies recorded during each sampling did not differ between dry and rainy seasons, but the mean richness of galls per plot was higher in the rainy season. In conclusion, natural factors, such as vegetation structure and seasonality, were more important for the distribution of gall-inducing species than anthropic factors, such as vegetation anthropization level.(AU)

New reports of host plants of Euchistus nicaraguensis Rolston, 1972 (Heteroptera: Pentatomidae) and natural parasitism of Telenomus podisi Ashmead, 1893 (Hymenoptera: Platygastridae) in the rice agricultural ecosystem in Panama

The subfamily Pentatominae, which includes Euschistus nicaraguensis Rolston, 1972, presents 116 genera and aproximately more than 667 species, reported for the Neotropical region (Grazia et al., 2015). The geographical distribution of this species comprehends diverse countries in Central America, between Panama and Honduras (Rolston, 1974), reporting species of weeds in rice crops (Rolston, 1974; Maes, 1994). In spite of the occurrence reports of E. nicaraguensis, of rice crops in Panama (Rolston, 1974; Maes, 1994; Arismendi, 2002), the presence of this species of Pentatomidae is sporadic and its population reduced. Nevertheless, the colonization, adaptation, and biological development of E. nicaraguensis with the species complex of weeds associated with the agricultural ecosystem of rice, have been least studied. In a similar manner, the interaction between the natural control of this insect species with the population of biological control agents and specifically the eggs parasitoids, is considered as a new association between E. nicaraguensis and Telenomus podisi Ashmead, 1893, defined as a fundamental component in the integral management of the agricultural ecosystem of rice. The present report evidences the importance of this species, as a potential insect-pest, to the extent in which the biotic and abiotic factors, among other variables, promote the increase of E. nicaraguensis population. The identification of the species E. nicaraguensis, was performed by Dr. Jocelia Grazia, from the Department of Zoology, of the Universidade Federal de Rio Grande do Sul, Porto Alegre, Brazil. The samplings were performed in June 2016, in extensive areas of rice production from the IDIAP-38 variety, between the floration and milky stage, in the location of Juan Hombron, province of Cocle, Panama (08°2383”N; 08°1390”O). The average temperature and relative humidity, in the sampled plots, was 32.8 °C and 82%, respectively. It is highlighted that the average temperature and relative humidity, in this productive region of rice was of 30.0 °C and 80%, for the last five year period (2010-2015). The total number of samples collected randomly was 15, in a crop area of 8 hectares, free from insecticide application. The recollection of eggs and adults of E. nicaraguensis, was performed by means of sweep net and by visual methods. The samples in the complex of host weeds of E. nicaraguensis was performed in areas next to the experimental plot, visually examining and collecting egg masses by square meter m2, totaling 20 samples, in the experimental plots. The collected egg masses were individually placed in glass Petri dishes (9.0 × 1.5 cm), maintaining the internal humidity by the moistened filter paper with distilled water, placed at the base. Later, the egg masses were transferred to controlled climate chambers regulated at 28±1 °C of temperature, 85±3% of relative humidity and 12 hours of photophase, with the purpose of waiting for the emergence of parasitoids. The parasitism rate of eggs, was determined by the formula P [(% = number of eggs parasitized /total number of eggs submitted to parasitism) 100]. The nymphs that hatched were maintained under controlled abiotic conditions, until the adult stage was reached and confirmed that the parasitized eggs belong to E. nicaraguensis.(AU)

Representativity of the genus Asphondylia Loew, 1850 (Diptera, Cecidomyiidae) in Brazil

Representativity of the genus Asphondylia Loew, 1850 (Diptera, Cecidomyiidae) in Brazil. This cosmopolitan genus includes 272 galling species described, of which about 100 occur in the Neotropical Region. The present study goal to evaluate the richness of Asphondylia in Brazil, to provide an updated list of the host plant species, to determine the plant organs where galls are induced, to update the geographic distribution of the genus, to verify it distribution in the Brazilian biomes, and to the list the associated fauna. The survey data was carried out by consulting the Cecidomyiidae collection of the Museu Nacional/UFRJ, the database “Web of Science” using Asphondylia and Brasil/Brazil as keywords, 51 Brazilian inventories and two catalogues. Asphondylia is represented by 58 species in Brazil, among them, twenty are already known and 38 are still undetermined. The Brazilian described species represent 8% of the total of known species of Asphondylia in the world and 21% of species of the Neotropical fauna. This genus is associated with 51 plant species and 20 plant families in Brazil. Asteraceae comprise the greatest richness of Asphondylia species. This genus was found in five biomes, among them the Atlantic forest has the highest species richness. The associated fauna comprises parasitoids (Hymenoptera) and inquilines (Lepidoptera, Coleoptera and Diptera).

Representatividade do gênero Asphondylia Loew, 1850 (Diptera, Cecidomyiidae) no Brasil. Este gênero cosmopolita inclui 272 espécies galhadoras descritas, das quais cerca de 100 ocorrem na Região Neotropical. O objetivo deste estudo foi avaliar a riqueza de Asphondylia no Brasil, fornecer uma lista atualizada das espécies de plantas hospedeiras, determinar os órgãos das plantas onde as galhas são induzidas, atualizar a distribuição geográfica do gênero, verificar sua distribuição nos biomas do Brasil e uma lista da fauna associada. Os dados da pesquisa foram realizados consultando a coleção de Cecidomyiidae do Museu Nacional/UFRJ, a base de dados “Web of Science”, utilizando as palavras Asphondylia e Brasil/Brazil, 51 inventários brasileiros e dois catálogos. Asphondylia é representada por 58 espécies no Brasil, entre elas, 20 são já conhecidas e 38 ainda são indeterminadas. As espécies descritas no Brasil representam 8% do total de espécies conhecidas de Asphondylia no mundo e 21% das espécies da fauna Neotropical. Este gênero está associado a 51 espécies de plantas e 20 famílias de plantas no Brasil. As Asteraceae hospedam a maior riqueza de espécies de Asphondylia. Este gênero foi encontrado em cinco biomas, entre eles a Mata Atlântica obteve a maior riqueza de espécies. A fauna associada compreende parasitóides (Hymenoptera) e inquilinos (Lepidoptera, Coleoptera e Diptera).

Representativity of the genus Asphondylia Loew, 1850 (Diptera, Cecidomyiidae) in Brazil

Representativity of the genus Asphondylia Loew, 1850 (Diptera, Cecidomyiidae) in Brazil. This cosmopolitan genus includes 272 galling species described, of which about 100 occur in the Neotropical Region. The present study goal to evaluate the richness of Asphondylia in Brazil, to provide an updated list of the host plant species, to determine the plant organs where galls are induced, to update the geographic distribution of the genus, to verify it distribution in the Brazilian biomes, and to the list the associated fauna. The survey data was carried out by consulting the Cecidomyiidae collection of the Museu Nacional/UFRJ, the database “Web of Science” using Asphondylia and Brasil/Brazil as keywords, 51 Brazilian inventories and two catalogues. Asphondylia is represented by 58 species in Brazil, among them, twenty are already known and 38 are still undetermined. The Brazilian described species represent 8% of the total of known species of Asphondylia in the world and 21% of species of the Neotropical fauna. This genus is associated with 51 plant species and 20 plant families in Brazil. Asteraceae comprise the greatest richness of Asphondylia species. This genus was found in five biomes, among them the Atlantic forest has the highest species richness. The associated fauna comprises parasitoids (Hymenoptera) and inquilines (Lepidoptera, Coleoptera and Diptera).(AU)

Representatividade do gênero Asphondylia Loew, 1850 (Diptera, Cecidomyiidae) no Brasil. Este gênero cosmopolita inclui 272 espécies galhadoras descritas, das quais cerca de 100 ocorrem na Região Neotropical. O objetivo deste estudo foi avaliar a riqueza de Asphondylia no Brasil, fornecer uma lista atualizada das espécies de plantas hospedeiras, determinar os órgãos das plantas onde as galhas são induzidas, atualizar a distribuição geográfica do gênero, verificar sua distribuição nos biomas do Brasil e uma lista da fauna associada. Os dados da pesquisa foram realizados consultando a coleção de Cecidomyiidae do Museu Nacional/UFRJ, a base de dados “Web of Science”, utilizando as palavras Asphondylia e Brasil/Brazil, 51 inventários brasileiros e dois catálogos. Asphondylia é representada por 58 espécies no Brasil, entre elas, 20 são já conhecidas e 38 ainda são indeterminadas. As espécies descritas no Brasil representam 8% do total de espécies conhecidas de Asphondylia no mundo e 21% das espécies da fauna Neotropical. Este gênero está associado a 51 espécies de plantas e 20 famílias de plantas no Brasil. As Asteraceae hospedam a maior riqueza de espécies de Asphondylia. Este gênero foi encontrado em cinco biomas, entre eles a Mata Atlântica obteve a maior riqueza de espécies. A fauna associada compreende parasitóides (Hymenoptera) e inquilinos (Lepidoptera, Coleoptera e Diptera).(AU)

Infection process of Phakopsora gossypii in cotton leaves

Tropical rust caused by the biotrophic fungus Phakopsora gossypii is an emerging disease in cotton that has caused significant yield losses of crop/cotton cultivated in Brazil. Considering the current importance of tropical rust and the need to obtain additional basic information about its causal agent to better control this disease, the present study aimed to determine the infection process of P. gossypii in cotton leaves using scanning electron microscopy (SEM). Thirty-day-old plants were inoculated with a suspension of P. gossypii uredospores, and leaf fragments were collected 42 h after inoculation (hai) as well as 20, 25 and 35 days after inoculation (dai) for SEM observations. By 42 hai, the uredospores of P. gossypii had germinated and produced a germ tube and an appressorium that may directly penetrate the leaf cuticle. At 20 dai, closed uredia containing uredospores were observed on the abaxial leaf surface. At 25 dai, the uredia started to open and became fully open by 35 dai and contained many uredospores. By 25 dai, fungal hyphae were growing abundantly in the mesophyll next to the uredia that formed in the leaf fragments with total or partial removal of the epidermis. The results of the present study provide novel information regarding the infection process of P. gossypii in cotton leaves, which might be useful for the development of new and more effective strategies for tropical rust control.

Infection process of Phakopsora gossypii in cotton leaves

Tropical rust caused by the biotrophic fungus Phakopsora gossypii is an emerging disease in cotton that has caused significant yield losses of crop/cotton cultivated in Brazil. Considering the current importance of tropical rust and the need to obtain additional basic information about its causal agent to better control this disease, the present study aimed to determine the infection process of P. gossypii in cotton leaves using scanning electron microscopy (SEM). Thirty-day-old plants were inoculated with a suspension of P. gossypii uredospores, and leaf fragments were collected 42 h after inoculation (hai) as well as 20, 25 and 35 days after inoculation (dai) for SEM observations. By 42 hai, the uredospores of P. gossypii had germinated and produced a germ tube and an appressorium that may directly penetrate the leaf cuticle. At 20 dai, closed uredia containing uredospores were observed on the abaxial leaf surface. At 25 dai, the uredia started to open and became fully open by 35 dai and contained many uredospores. By 25 dai, fungal hyphae were growing abundantly in the mesophyll next to the uredia that formed in the leaf fragments with total or partial removal of the epidermis. The results of the present study provide novel information regarding the infection process of P. gossypii in cotton leaves, which might be useful for the development of new and more effective strategies for tropical rust control.(AU)

Host status of passion fruit genotypes to scab and bacterial blight / Hospedabilidade de genótipos de maracujazeiro a verrugose e bacteriose

Screening passion fruit genotypes to target resistance to scab and bacterial blight may play an important role in reducing the application of chemical products and decreasing losses caused by these diseases. It is likely that resistant genotypes can be found in ongoing breeding programs targeting production traits. Thus, the objective of this work was to evaluate the host status of eighteen passion fruit genotypes from the Breeding Program of the Universidade Federal de Viçosa (CRP 01-12 to CRP 16-12, CRP 19-12 and CRP 20-12) and two cultivars (FB 200 Yellow Master and FB 300 Araguari) of yellow passion fruit to scab (Cladosporium herbarum) and bacterial blight (Xanthomonas axonopodis pv. passiflorae). The fungus and the bacterium were artificially inoculated on wounded leaves at concentrations of 1 x 106 spores mL-1 and 1 x 108 cfu mL-1. Scab incidence and severity were assessed at 7, 14, 21, and 31 days after inoculation (DAI); whereas bacterial blight evaluations were performed at 10, 20, 28, and 44 DAI. The genotypes CRP 01-12 to CRP 16-12 and CRP 19-12 are moderately resistant to scab. All genotypes are highly susceptible to bacterial blight.

A seleção de genótipos de maracujazeiro visando resistência à verrugose e bacteriose pode ter importante papel na redução da aplicação de produtos químicos e perdas causadas por essas doenças. É provável que genótipos resistentes possam ser encontrados em programas de melhoramento visando seleção de caracteres relacionados à produção. Assim, o objetivo deste trabalho foi avaliar a hospedabilidade de dezoito genótipos de maracujazeiro-azedo provenientes do Programa de Melhoramento Genético da Universidade Federal de Viçosa (CRP 01-12 a CRP 16-12, CRP 19-12 e CRP 20-12) e dois cultivares comerciais (FB 200 Yellow Master e FB 300 Araguari) à verrugose (causada por Cladosporium herbarum) e bacteriose (Xanthomonas axonopodis pv. passiflorae). O fungo e a bactéria foram inoculados em folhas com ferimentos nas concentrações de 1 x 106 esporos mL-1 e 1 x 108 ufc mL-1. A incidência e a severidade de verrugose foram avaliadas aos 7, 14, 21 e 31 dias após a inoculação (DAI); enquanto que as avaliações da bacteriose foram aos 10, 20, 28 e 44 DAI. Os genótipos CRP 01-12 a CRP 16-12 e CRP 19-12 são moderamente resistentes à verrugose. Todos os genótipos são altamente suscetíveis à bacteriose.

Host status of passion fruit genotypes to scab and bacterial blight / Hospedabilidade de genótipos de maracujazeiro a verrugose e bacteriose

Screening passion fruit genotypes to target resistance to scab and bacterial blight may play an important role in reducing the application of chemical products and decreasing losses caused by these diseases. It is likely that resistant genotypes can be found in ongoing breeding programs targeting production traits. Thus, the objective of this work was to evaluate the host status of eighteen passion fruit genotypes from the Breeding Program of the Universidade Federal de Viçosa (CRP 01-12 to CRP 16-12, CRP 19-12 and CRP 20-12) and two cultivars (FB 200 Yellow Master and FB 300 Araguari) of yellow passion fruit to scab (Cladosporium herbarum) and bacterial blight (Xanthomonas axonopodis pv. passiflorae). The fungus and the bacterium were artificially inoculated on wounded leaves at concentrations of 1 x 106 spores mL-1 and 1 x 108 cfu mL-1. Scab incidence and severity were assessed at 7, 14, 21, and 31 days after inoculation (DAI); whereas bacterial blight evaluations were performed at 10, 20, 28, and 44 DAI. The genotypes CRP 01-12 to CRP 16-12 and CRP 19-12 are moderately resistant to scab. All genotypes are highly susceptible to bacterial blight.(AU)

A seleção de genótipos de maracujazeiro visando resistência à verrugose e bacteriose pode ter importante papel na redução da aplicação de produtos químicos e perdas causadas por essas doenças. É provável que genótipos resistentes possam ser encontrados em programas de melhoramento visando seleção de caracteres relacionados à produção. Assim, o objetivo deste trabalho foi avaliar a hospedabilidade de dezoito genótipos de maracujazeiro-azedo provenientes do Programa de Melhoramento Genético da Universidade Federal de Viçosa (CRP 01-12 a CRP 16-12, CRP 19-12 e CRP 20-12) e dois cultivares comerciais (FB 200 Yellow Master e FB 300 Araguari) à verrugose (causada por Cladosporium herbarum) e bacteriose (Xanthomonas axonopodis pv. passiflorae). O fungo e a bactéria foram inoculados em folhas com ferimentos nas concentrações de 1 x 106 esporos mL-1 e 1 x 108 ufc mL-1. A incidência e a severidade de verrugose foram avaliadas aos 7, 14, 21 e 31 dias após a inoculação (DAI); enquanto que as avaliações da bacteriose foram aos 10, 20, 28 e 44 DAI. Os genótipos CRP 01-12 a CRP 16-12 e CRP 19-12 são moderamente resistentes à verrugose. Todos os genótipos são altamente suscetíveis à bacteriose.(AU)

Efeito dos óleos essenciais de Thymus vulgaris, Origanum vulgare e dos terpenos timol e carvacrol, sobre adultos e massas ovígeras de Pseudosuccinea columella

A fasciolose é uma doença de distribuição mundial que pode levar a grandes prejuízos econômicos na criação de ruminantes e possui como hospedeiro intermediário moluscos aquáticos, sendo Pseudossucinea columella uma das espécies mais frequentes. Os moluscicidas sintéticos são indicados para o controle dos moluscos, entretanto, são tóxicos para diversas espécies de plantas e animais, sendo prejudiciais ao meio ambiente. Devido a necessidade da busca de novas substâncias naturais, menos nocivas ao meio ambiente e que possam atuar no controle de moluscos, o objetivo do estudo foi avaliar o efeito dos óleos essenciais de Thymus vulgaris, Origanum vulgare edos terpenos timol e carvacrol, sobre adultos e massas ovígeras de P. columella. Os óleos de T. vulgaris, O. vulgare e os majoritários, timol e carvacrol, foram diluídos nas concentrações de 10, 20, 40, 60, 80 e 100 ppm, como controle positivo se utilizou o sulfato de cobre (CuSo4) e como controle negativo se utilizou a água potável (H2O) e o Dimetilsulfóxido (DMSO) 1% (diluente das soluções). Os moluscos foram divididos em grupos de 10 espécimes para cada solução, foram expostas as diferentes soluções teste pelo período de 24 horas e avaliados durante esse período nos tempos de 30 minutos, duas, seis, 12 e 24 horas. A mesma metodologia foi utilizada com as massas ovígeras, entretanto, as massas foram expostas as substâncias por 24 horas, passaram pelo processo de lavagem e foram avaliadas por 18 dias após exposição. Durante o estudo biológico dos moluscos adultos se observou que os óleos essenciais de orégano nas concentrações de 60, 80 e 100 ppm e tomilho na concentração de 100 ppm levaram a morte de 100% dos e se mostraram dentro das normas estabelecidas pela Organização Mundial da Saúde para uma mistura complexa de substâncias. Os óleos essenciais e componentes majoritários se mostraram efetivos na inibição do crescimento e da eclosão das massas. Somente as massas expostas ao majoritário timol, nas concentrações de 10, 20 e 40 ppm, eclodiram. Em relação a histologia, foi possível observar vacuolizações e fragmentação nos tecidos de glândula digestiva, ovotestis e manto nos moluscos tratados com os óleos essenciais e os componentes majoritários. Notou-se ainda na histologia, áreas de autólise em moluscos tratados com timol na concentração de 80 ppm. Na Microscopia Eletrônica de Varredura (MEV) encontraram-se alteraçõesteciduais em glândula digestiva e manto nas concentrações de 100 ppm dos óleos essenciais e seus componentes majoritários. Assim, pode-se concluir que os óleos essências de O. vulgare e T. vulgaris se comportaram como substâncias moluscicidas em P. columella. Além disso, notou-se efeitos inibitórios no crescimento e eclosão das massas ovígeras tratadas com os componentes majoritários e os óleos essenciais estudados.

Fasciolosis is a disease with worldwide distribution that can lead to great economic losses in ruminant breeding and has aquatic molluscs as an intermediate host, with Pseudosucinea columella being one of the most frequent species. Synthetic molluscicides are indicated for the control of molluscs, however, they are toxic to several species of plants and animals, being harmful to the environment. Due to the need to search for new natural substances, less harmful to the environment and that can act in the control of molluscs, the aim of the study was to evaluate the effect of essential oils from Thymus vulgaris, Origanum vulgare and terpenes thymol and carvacrol, on adults and ovigerous masses of P. columella. The oils of T. vulgaris, O. vulgare and the major ones, thymol and carvacrol, were diluted in concentrations of 10, 20, 40, 60, 80 and 100 ppm, as a positive control using copper sulfate (CuSo4) and as negative control, drinking water (H2O) and 1% Dimethylsulfoxide (DMSO) (solutions diluent) were used. The molluscs were divided into groups of 10 specimens for each solution, the different test solutions were exposed for a period of 24 hours and evaluated during this period at times of 30 minutes, two, six, 12 and 24 hours. The same methodology was used with the ovigerous masses, however, the masses were exposed to substances for 24 hours, went through the washing process and were evaluated for 18 days after exposure. During the biological study of adult molluscs, it was observed that essential oils of oregano at concentrations of 60, 80 and 100 ppm and thyme at a concentration of 100 ppm led to the death of 100% of them and were within the standards established by the World Health Organization for a complex mixture of substances. Essential oils and major components proved to be effective in inhibiting the growth and hatching of doughs. Only the masses exposed to the majority of thymol, at concentrations of 10, 20 and 40 ppm, hatched. Regarding histology, it was possible to observe vacuolization and fragmentation in the tissues of the digestive gland, ovotestis and mantle in molluscs treated with essential oils and major components. It was also noted in histology, areas of autolysis in molluscs treated with thymol at a concentration of 80 ppm. Scanning Electron Microscopy (SEM) showed tissue changes in the digestive gland and mantle at 100 ppm concentrations of essential oils and their major components. Thus, it can be concluded that the essential oils of O. vulgare and T. vulgaris behaved as molluscicide substances in P. columella. In addition, inhibitory effects were noted on the growth and hatching of ovigerous masses treated with the major components and essential oils studied.

Mycorrhizal colonization and diversity and corn genotype yield in soils of the Cerrado region, Brazil / Colonização e diversidade micorrízica e produtividade de genótipos de milho, em solo de Cerrado

The degree of interaction between arbuscular mycorrhizal fungi (AMF) and host plants appears to depend on plant genotype, which differentially promotes symbiosis and leads to different degree of mycotrophism. The aim of the present study was to assess root colonization, spore density, and diversity of AMF, as well as yield of corn (Zea mays) genotypes in soil from the Cerrado region of Brazil. Number of spores (NS), mycorrhizal colonization (COL), plant and ear height, dry weight (DW), and grain yield (GY) were assessed in inbred lines and their hybrids. Randomized blocks were used for the experimental design, with 30 treatments (genotypes) and three repetitions. The experiment was conducted on the farm of the UNESP-São Paulo State University, Campus of Ilha Solteira, and the plots were composed of two 2-m-long rows, with 0.85 m between rows, and 0.20 m between plants. Qualitative and quantitative changes were observed in fungal compositions, as well as preferential associations between symbiotic partners. Analysis of AMF diversity revealed the presence of 12 species, with Scutellospora calospora and Entrophospora colombiana being the most abundant in all treatments. The species Acaulospora longula, Glomus etunicatum, Glomus macrocarpum, and Gigaspora margarita exhibited preferential associations with certain genotypes. COL and GY differed among inbred lines and single-cross hybridsand the significant correlations between COL and the DW and GY showed positive interactions between the plants and AMF. There was no correlation between heterosis for GY and heterosis for colonization. These single-cross hybrids HS83 × E3 and D3 × F5 exhibited high GY, evidencing a productivity potential for the low technological condition used.(AU)

O grau de interação entre o fungo micorrízico arbuscular (FMA) e a planta hospedeira parece depender do genótipo da planta, o qual estimula diferentemente a simbiose, acarretando um menor ou maior grau de micotrofismo. Este trabalho objetivou verificar a colonização radicular, densidade de esporos e diversidade de FMA e produtividade de genótipos de milho, no cerrado. Foram avaliados o número de esporos, colonização micorrízica (COL), altura da planta e da inserção de espiga, massa de matéria seca (MS) e produtividade de grãos (PROD) em linhagens endogâmicas e híbridos. O delineamento experimental foi em blocos casualizados, com 30 tratamentos (genótipos) e três repetições. O experimento foi implantado na Fazenda de Pesquisa, Ensino e Extensão da UNESP-Univ Estadual Paulista, Campus de Ilha Solteira, sendo as parcelas constituídas de duas linhas de 2 m de comprimento, espaçadas de 0,85 m entre linhas e 0,20 m entre plantas. Observou-se a ocorreram mudanças qualitativas e quantitativas na composição fúngica, com associações preferenciais entre os genótipos. Para diversidade de FMA foram constatadas 12 espécies, sendo Scutellospora calospora e Entrophospora colombiana as espécies de maior ocorrência para todos os tratamentos. As espécies Acaulospora longula, Glomus etunicatum, Glomus macrocarpum e Glomus margarita exibiram associações preferenciais entre os genótipos. ACOL e a PROD diferiram entre linhagens e entre híbridos e as correlações significativas entre COL e a MS e PROD evidenciam interações positiva entre planta e FMA. A heterose para PROD não mostrou correlação com a heterose da colonização. Os híbridos HS83 x E3 e D3 x F5 exibiram alta PROD, evidenciando um potencial produtivo para as condições tecnológicas utilizadas.(AU)

Mycorrhizal colonization and diversity and corn genotype yield in soils of the Cerrado region, Brazil / Colonização e diversidade micorrízica e produtividade de genótipos de milho, em solo de Cerrado

The degree of interaction between arbuscular mycorrhizal fungi (AMF) and host plants appears to depend on plant genotype, which differentially promotes symbiosis and leads to different degree of mycotrophism. The aim of the present study was to assess root colonization, spore density, and diversity of AMF, as well as yield of corn (Zea mays) genotypes in soil from the Cerrado region of Brazil. Number of spores (NS), mycorrhizal colonization (COL), plant and ear height, dry weight (DW), and grain yield (GY) were assessed in inbred lines and their hybrids. Randomized blocks were used for the experimental design, with 30 treatments (genotypes) and three repetitions. The experiment was conducted on the farm of the UNESP-São Paulo State University, Campus of Ilha Solteira, and the plots were composed of two 2-m-long rows, with 0.85 m between rows, and 0.20 m between plants. Qualitative and quantitative changes were observed in fungal compositions, as well as preferential associations between symbiotic partners. Analysis of AMF diversity revealed the presence of 12 species, with Scutellospora calospora and Entrophospora colombiana being the most abundant in all treatments. The species Acaulospora longula, Glomus etunicatum, Glomus macrocarpum, and Gigaspora margarita exhibited preferential associations with certain genotypes. COL and GY differed among inbred lines and single-cross hybridsand the significant correlations between COL and the DW and GY showed positive interactions between the plants and AMF. There was no correlation between heterosis for GY and heterosis for colonization. These single-cross hybrids HS83 × E3 and D3 × F5 exhibited high GY, evidencing a productivity potential for the low technological condition used.

O grau de interação entre o fungo micorrízico arbuscular (FMA) e a planta hospedeira parece depender do genótipo da planta, o qual estimula diferentemente a simbiose, acarretando um menor ou maior grau de micotrofismo. Este trabalho objetivou verificar a colonização radicular, densidade de esporos e diversidade de FMA e produtividade de genótipos de milho, no cerrado. Foram avaliados o número de esporos, colonização micorrízica (COL), altura da planta e da inserção de espiga, massa de matéria seca (MS) e produtividade de grãos (PROD) em linhagens endogâmicas e híbridos. O delineamento experimental foi em blocos casualizados, com 30 tratamentos (genótipos) e três repetições. O experimento foi implantado na Fazenda de Pesquisa, Ensino e Extensão da UNESP-Univ Estadual Paulista, Campus de Ilha Solteira, sendo as parcelas constituídas de duas linhas de 2 m de comprimento, espaçadas de 0,85 m entre linhas e 0,20 m entre plantas. Observou-se a ocorreram mudanças qualitativas e quantitativas na composição fúngica, com associações preferenciais entre os genótipos. Para diversidade de FMA foram constatadas 12 espécies, sendo Scutellospora calospora e Entrophospora colombiana as espécies de maior ocorrência para todos os tratamentos. As espécies Acaulospora longula, Glomus etunicatum, Glomus macrocarpum e Glomus margarita exibiram associações preferenciais entre os genótipos. ACOL e a PROD diferiram entre linhagens e entre híbridos e as correlações significativas entre COL e a MS e PROD evidenciam interações positiva entre planta e FMA. A heterose para PROD não mostrou correlação com a heterose da colonização. Os híbridos HS83 x E3 e D3 x F5 exibiram alta PROD, evidenciando um potencial produtivo para as condições tecnológicas utilizadas.

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in cotton: vertical distribution of egg masses, effects of adult density and plant age on oviposition behavior

The objective of this work was to determine the most suitable density of adults per plant, ideal plant age, and vertical distribution of eggs in different parts of the plant in a greenhouse investigation for future resistance studies and improvement of S. frugiperda management practices in cotton. The experiments of Spodotera frugiperda oviposition in relation to adult density, relationship between cotton plant age and Spodoptera frugiperda oviposition, Spodoptera frugiperda non-preference for oviposition on cotton varieties were conducted with plants of cotton variety BRS Ita 90. The experiments were conducted with plants of cotton variety BRS Ita 90. Non-preference (antixenosis) for oviposition was studied in FiberMax 966, FiberMax 977, DeltaOpal, DeltaPenta, Acala 90, Coodetec 408, Coodetec 409, Coodetec 410, BRS Cedro, BRS Ipê, BRS Aroeira, IPR 96, IPR 20, BRS Araçá, IAC 24, and BRS Ita 90 varieties. We concluded that the fall armyworm S. frugiperda prefers to oviposit on plants with approximately 60 days of age, on the lower surface of leaves located in the upper third of the plant tests under greenhouse conditions. A density of at least three pairs of S. frugiperda adults per plant was sufficient to conduct non-preference-for-oviposition tests under greenhouse conditions. Coodetec 408, BRS Aroeira, BRS Araçá, BRS Ita 90 and DeltaPenta varieties showed non-preference-for-oviposition resistance to S. frugiperda. In regions with high infestations of S. frugiperda, it would be prudent for the cultivation the use of BRS Ita 90 cotton variety.

O trabalho teve por objetivo determinar, em casa-de-vegetação, a densidade adequada de adultos, a idade ideal das plantas e a distribuição vertical de ovos nas diferentes partes da planta, visando à realização de estudos de resistência e à melhoria das práticas de manejo de Spodoptera frugiperda em algodoeiro. Os experimentos de oviposição de S. frugiperda em relação à densidade de adultos, relação entre plantas de algodoeiro e oviposição de S. frugiperda e não preferência para oviposição de S. frugiperda em variedades de algodoeiro foram realizados com plantas da variedade de algodoeiro BRS Ita 90. A não preferência (antixenose) para oviposição foi acompanhada nas variedades FiberMax 966, FiberMax 977, DeltaOpal, DeltaPenta, Acala 90, Coodetec 408, Coodetec 409, Coodetec 410, BRS Cedro, BRS Ipê, BRS Aroeira, IPR 96, IPR 20, BRS Araçá, IAC 24 e BRS Ita 90. Concluiu-se que S. frugiperda prefere ovipositar em plantas com cerca de 60 dias de idade, na superfície inferior das folhas situadas no terço superior dos testes de plantas sob condições de estufa. Uma densidade de, pelo menos, três pares de adultos S. frugiperda por planta foi suficiente para realizar testes de não preferência para oviposição em casa de vegetação. As variedades Coodetec 408, BRS Aroeira, BRS Araçá, BRS Ita 90 e DeltaPenta apresentaram resistência do tipo não preferência para oviposição de S. frugiperda. Em regiões com altas infestações de S. frugiperda, seria prudente para o cultivo utilizar a variedade de algodão BRS Ita 90.

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in cotton: vertical distribution of egg masses, effects of adult density and plant age on oviposition behavior / Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) em algodoeiro: distribuição vertical de posturas, efeitos da densidade de adultos e da idade das plantas sobre o comportamento de oviposição

The objective of this work was to determine the most suitable density of adults per plant, ideal plant age, and vertical distribution of eggs in different parts of the plant in a greenhouse investigation for future resistance studies and improvement of S. frugiperda management practices in cotton. The experiments of Spodotera frugiperda oviposition in relation to adult density, relationship between cotton plant age and Spodoptera frugiperda oviposition, Spodoptera frugiperda non-preference for oviposition on cotton varieties were conducted with plants of cotton variety BRS Ita 90. The experiments were conducted with plants of cotton variety BRS Ita 90. Non-preference (antixenosis) for oviposition was studied in FiberMax 966, FiberMax 977, DeltaOpal, DeltaPenta, Acala 90, Coodetec 408, Coodetec 409, Coodetec 410, BRS Cedro, BRS Ipê, BRS Aroeira, IPR 96, IPR 20, BRS Araçá, IAC 24, and BRS Ita 90 varieties. We concluded that the fall armyworm S. frugiperda prefers to oviposit on plants with approximately 60 days of age, on the lower surface of leaves located in the upper third of the plant tests under greenhouse conditions. A density of at least three pairs of S. frugiperda adults per plant was sufficient to conduct non-preference-for-oviposition tests under greenhouse conditions. Coodetec 408, BRS Aroeira, BRS Araçá, BRS Ita 90 and DeltaPenta varieties showed non-preference-for-oviposition resistance to S. frugiperda. In regions with high infestations of S. frugiperda, it would be prudent for the cultivation the use of BRS Ita 90 cotton variety.

O trabalho teve por objetivo determinar, em casa-de-vegetação, a densidade adequada de adultos, a idade ideal das plantas e a distribuição vertical de ovos nas diferentes partes da planta, visando à realização de estudos de resistência e à melhoria das práticas de manejo de Spodoptera frugiperda em algodoeiro. Os experimentos de oviposição de S. frugiperda em relação à densidade de adultos, relação entre plantas de algodoeiro e oviposição de S. frugiperda e não preferência para oviposição de S. frugiperda em variedades de algodoeiro foram realizados com plantas da variedade de algodoeiro BRS Ita 90. A não preferência (antixenose) para oviposição foi acompanhada nas variedades FiberMax 966, FiberMax 977, DeltaOpal, DeltaPenta, Acala 90, Coodetec 408, Coodetec 409, Coodetec 410, BRS Cedro, BRS Ipê, BRS Aroeira, IPR 96, IPR 20, BRS Araçá, IAC 24 e BRS Ita 90. Concluiu-se que S. frugiperda prefere ovipositar em plantas com cerca de 60 dias de idade, na superfície inferior das folhas situadas no terço superior dos testes de plantas sob condições de estufa. Uma densidade de, pelo menos, três pares de adultos S. frugiperda por planta foi suficiente para realizar testes de não preferência para oviposição em casa de vegetação. As variedades Coodetec 408, BRS Aroeira, BRS Araçá, BRS Ita 90 e DeltaPenta apresentaram resistência do tipo não preferência para oviposição de S. frugiperda. Em regiões com altas infestações de S. frugiperda, seria prudente para o cultivo utilizar a variedade de algodão BRS Ita 90.

INTERAÇÕES COM PLANTAS E BIOLOGIA COMPARADA DO PERCEVEJO Thyanta perditor (Fabricius, 1794) (HETEROPTERA: PENTATOMIDAE) NO NORTE DO RIO GRANDE DO SUL

Thyanta perditor (F.) (Heteroptera: Pentatomidae) é um percevejo Neotropical, com ampla distribuição em vários países da América do Sul. É comumente encontrado em campos cultivados, mas há pouca informação disponível sobre sua bioecologia. Deste modo, estudos sobre a sua flutuação populacional, preferência e biologia de ninfas e adultos em plantas cultivadas e não-cultivadas foram realizados durante o ano de 2016. Foi avaliada semanalmente a presença do percevejo em campos cultivados, áreas em pousio e vegetação nativa. Foi observado que T. perditor foi encontrado em maior quantidade nos meses quentes, com o pico populacional no mês de março, coincidindo com a maturação da cultura da soja, Glycine max (L.) Merrill. Os testes da preferência por plantas cultivadas [soja, milho (Zea mays L.), trigo (Triticum aestivum L.) e cevada (Hordeum vulgare L.)] e não-cultivadas [picão-preto (Bidens pilosa L.), buva (Conyza bonariensis L.), capim-papuã (Brachiaria plantaginea Link) e leiteiro (Euphorbia heterophylla L.)], utilizando plântulas em gaiolas de criação tipo Bugdorm I, indicaram que os percevejos demonstraram preferência por plântulas de soja e milho, e também por leiteiro, picão-preto e buva. Ninfas do percevejo conseguiram completar seu ciclo utilizando como alimento sementes de picão-preto (maduras e imaturas) e espigas de trigo e cevada (imaturas); nenhuma ninfa passou do segundo instar quando alimentadas com plântulas de quaisquer das espécies testadas. Os adultos alimentados com planta de picão-preto fresca, semente de milho (imatura) e espiga de trigo (imatura) apresentaram sobrevivência média/alta (variação de 50% à 90%), os melhores desempenhos reprodutivos (100% das fêmeas ovipositaram) e ganho de peso; os percevejos alimentados com espiga de cevada (imatura), vagem de feijão (Phaseolus vulgaris L.) (imatura), semente de picão-preto (madura) e vagem de soja (imatura) apresentaram sobrevivência variável (de 20% à 100%); o desempenho reprodutivo variou de baixo (30%) a alto (80%) e o ganho de peso variou de +26% no primeiro à +39% no último alimento. Em inflorescência de picão-preto, semente de picão-preto (imatura) e fruto de leiteiro (imaturo), os adultos apresentaram baixa sobrevivência ( 10%), desempenho reprodutivo baixo (10%) ou nulo (0%) e perda de peso.

Thyanta perditor (F.) (Heteroptera: Pentatomidae) is a Neotropical stink bug, widely distributed in several countries of South America. It is commonly found in cultivated fields, but there is relatively few information available on its bioecology. Therefore, studies on its population dynamics, plant preference and biology of nymphs and adults on cultivated and on non-cultivated plants were conducted during the year of 2016. The presence of the stink bug was weekly evaluated on cultivated fields, in areas with crop residues and on the native vegetation. It was observed that T. perditor was greatly abundant in the warmer months, with the peak in population observed during March, at the time of soybean [Glycine max (L.) Merrill] maturation. Preference tests for cultivated [soybean, maize (Zea mays L.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.)] and for non-cultivated plants [black jack (Bidens pilosa L.), flax-leaf fleabane (Conyza bonariensis L.), signal grass (Brachiaria plantaginea Link) and milkweed (Euphorbia heterophylla L.)], using seedlings in cages type Bugdorm I, indicated that the stink bugs demonstrated preference for soybean and maize, and also for milkweed, black jack, and flax-leaf fleabane seedlings. Nymphs completed development on black jack seeds (mature and immature), and on wheat and barley seedheads (immature); no nymphs passed the second instar when fed on seedlings of any plants tested. Adults fed with fresh black jack plants, maize seed (immature) and wheat seedhead (immature) showed medium/high survivorship (range 50% to 90%), the best reproductive performance (100% of females ovipositing) and body weight gain; stink bugs fed on barley seedhead (immature), green bean (Phaseolus vulgaris L.) pods (immature), black jack seed (mature) and soybean pod (immature) showed variable survivorship (20% to 100%); reproductive performance varied from low (30% of females ovipositing) to high (80%), and weight gain varied from +26% on the first to +39% in the latter food. Black jack inflorescence and seed (mature), and milkweed fruit (immature) yielded low survivorship of adults ( 10%), low (10%) or null (0%) reproductive performance, and lost of body weight.

Occurrence of microtheca puntigera (achard) and microtheca semilaevis stal in five hosts in the field

ABSTRACT Microtheca punctigera (Achard) (Coleoptera: Chrysomelidae) is a major pest of Brassicaceae family plants in Brazil and occurs together with M. semilaevis. Occurrence of larvae and adults of M. punctigera and M. semilaevis Stal in five host plants grown in closely patchs was investigated in three periods in the field [Fall/Winter 2001 (May 10 to July 21); Fall 2002 (April 3 to June 12), and Spring 2002 (September 20 to November 15)]. Treatments were Chinese cabbage, mustard, watercress, arrugula and radish. The standard of occurrences of larvae of M. punctigera + M. semialevis was not repeated in the three trials: Chinese and mustard were the preferred food in 2001 Fall Winter while in the 2002 Fall and 2002 Spring preference was predominated for mustard and arrugula. M. punctigera was the predominant species during the experiments and populations were higher in the winter periods. In general, M. punctigera beetles were found mostly on Chinese cabbage and mustard, but in some assessments populations were high also in other hosts (mostly arugula). M. semialevis beetles occurred mostly on Chinese cabbage and mustard.

RESUMO Microtheca punctigera (Achard) é praga primária de plantas da família Brassicaceae no Brasil e ocorre associada com M. semilaevis Stal. Ocorrência de larvas e adultos de M. punctigera e M. semilaevis em cinco plantas hospedeiras em parcelas próximas foi avaliada em três períodos no campo ([outono/inverno, 2001 (10 de maio a 21 de julho); outono, 2002 (3 de abril a 12 de junho), e primavera, 2002 (20 de setembro a 15 de novembro)]. Os tratamentos foram couve chinesa, mostarda, agrião, rúcula e rabanete. O padrão de ocorrência de larva de M. punctigera + M. semialevis não se repetiu nos três períodos de avaliação: couve chinese e mostarda foram os alimentos preferidos no outono/inverno de 2001, enquanto que no outono e primavera de 2002, mostarda e rúcula foram os hospedeiros preferidos.M. punctigera foi a espécie predominante durante os experimentos e as populações foram maiores no período de inverno. De maneira geral, besouros de M. semialevis foram encontrados principalmente em couve chinesa e mostarda, mas em algumas as avaliações populações foram superiores em outros hospedeiros (principalmente em rúcula). Besouros de M. semialevis ocorreram principalmente em couve chinesa e mostarda.

Tomato yellow vein streak virus: relationship with Bemisia tabaci biotype B and host range

The Tomato yellow vein streak virus (ToYVSV) is a putative species of begomovirus, which was prevalent on tomato crops in São Paulo State, Brazil, until 2005. The objectives of this study were to evaluate the interaction between ToYVSV and its vector Bemisia tabaci biotype B and to identify alternative hosts for the virus. The minimum acquisition and inoculation access periods of ToYVSV by B. tabaci were 30 min and 10 min, respectively. Seventy five percent of tomato-test plants were infected when the acquisition and inoculation access periods were 24 h. The latent period of the virus in the insect was 16 h. The ToYVSV was retained by B. tabaci until 20 days after acquisition. First generation of adult whiteflies obtained from viruliferous females were virus free as shown by PCR analysis and did not transmit the virus to tomato plants. Out of 34 species of test-plants inoculated with ToYVSV only Capsicum annuum, Chenopodium amaranticolor, C. quinoa, Datura stramonium, Gomphrena globosa, Nicotiana clevelandii and N. tabacum cv. TNN were susceptible to infection. B. tabaci biotype B was able to acquire the virus from all these susceptible species, transmitting it to tomato plants.

O Tomato yellow vein streak virus (ToYVSV) é uma espécie putativa de begomovirus que infecta o tomateiro (Solanum lycopersicon) em diversas regiões do Brasil onde se cultiva essa solanácea, sendo a espécie prevalente no estado de São Paulo até 2005. Estudou-se a interação do ToYVSV com a Bemisia tabaci biótipo B e identificaram-se hospedeiras alternativas deste vírus. Os períodos de acesso mínimo de aquisição (PAA) e de inoculação (PAI) foram de 30 min e 10 min, respectivamente. A porcentagem de plantas infectadas chegou até cerca de 75% após um PAA e PAI de 24 h. O período de latência do vírus no vetor foi de 16 horas. O ToYVSV foi retido pela B. tabaci até 20 dias após a aquisição do vírus. Não foi detectada transmissão do vírus para progênie da B. tabaci biótipo B oriundas de insetos virulíferos. De 34 espécies de plantas testadas como hospedeiras somente Capsicum annuum, Chenopodium amaranticolor, C. quinoa, Datura stramonium, Gomphrena globosa, Nicotiana clevelandii e N. tabacum cv. TNN foram suscetíveis à infecção com o ToYVSV, por meio de inoculação com a B. tabaci. As espécies susceptíveis ao ToYVSV serviram de fonte de inóculo para a transmissão do vírus para tomateiros por meio de B. tabaci biótipo B.

Tomato yellow vein streak virus: relationship with Bemisia tabaci biotype B and host range

The Tomato yellow vein streak virus (ToYVSV) is a putative species of begomovirus, which was prevalent on tomato crops in São Paulo State, Brazil, until 2005. The objectives of this study were to evaluate the interaction between ToYVSV and its vector Bemisia tabaci biotype B and to identify alternative hosts for the virus. The minimum acquisition and inoculation access periods of ToYVSV by B. tabaci were 30 min and 10 min, respectively. Seventy five percent of tomato-test plants were infected when the acquisition and inoculation access periods were 24 h. The latent period of the virus in the insect was 16 h. The ToYVSV was retained by B. tabaci until 20 days after acquisition. First generation of adult whiteflies obtained from viruliferous females were virus free as shown by PCR analysis and did not transmit the virus to tomato plants. Out of 34 species of test-plants inoculated with ToYVSV only Capsicum annuum, Chenopodium amaranticolor, C. quinoa, Datura stramonium, Gomphrena globosa, Nicotiana clevelandii and N. tabacum cv. TNN were susceptible to infection. B. tabaci biotype B was able to acquire the virus from all these susceptible species, transmitting it to tomato plants.

O Tomato yellow vein streak virus (ToYVSV) é uma espécie putativa de begomovirus que infecta o tomateiro (Solanum lycopersicon) em diversas regiões do Brasil onde se cultiva essa solanácea, sendo a espécie prevalente no estado de São Paulo até 2005. Estudou-se a interação do ToYVSV com a Bemisia tabaci biótipo B e identificaram-se hospedeiras alternativas deste vírus. Os períodos de acesso mínimo de aquisição (PAA) e de inoculação (PAI) foram de 30 min e 10 min, respectivamente. A porcentagem de plantas infectadas chegou até cerca de 75% após um PAA e PAI de 24 h. O período de latência do vírus no vetor foi de 16 horas. O ToYVSV foi retido pela B. tabaci até 20 dias após a aquisição do vírus. Não foi detectada transmissão do vírus para progênie da B. tabaci biótipo B oriundas de insetos virulíferos. De 34 espécies de plantas testadas como hospedeiras somente Capsicum annuum, Chenopodium amaranticolor, C. quinoa, Datura stramonium, Gomphrena globosa, Nicotiana clevelandii e N. tabacum cv. TNN foram suscetíveis à infecção com o ToYVSV, por meio de inoculação com a B. tabaci. As espécies susceptíveis ao ToYVSV serviram de fonte de inóculo para a transmissão do vírus para tomateiros por meio de B. tabaci biótipo B.

Abundância, distribuição espacial de ninhos de abelhas Meliponina (Hymenoptera, Apidae, Apini) e espécies vegetais utilizadas para nidificação em áreas de cerrado do Maranhão

This study aimed at identifying the stingless bees species (Hymenoptera: Apidae, Apini, Meliponina) those were found in three study sites of cerrado, northeastern Brazil. The study also aimed identifying the plant species those were used as nesting sites by the stingless bees and verifying their characteristics. We intended to verify abundance and spatial distribution of the nests and patterns of the plants used as nesting sites. Seventy-three nests of 15 species were found. The most abundant species were Partamona chapadicola Pedro & Camargo, 2003 (34,25%) and Oxytrigona sp. 2 (20,55%). Eleven tree species were used as nesting sites. The most common host tree species was Qualea parviflora (Vochysiaceae) where 38,36% of the nests (n=28) nestled, followed by Salvertia convallariodora (Vochysiaceae) (n=17, 23,29%). The 95% confidence interval of DHB was between 36,21 cm and 41,68 cm. This interval is related with older trees that should have more hollows to be used as nesting sites. This process might be occurring with S. convallariodora and Q. parviflora. The patterns of spatial distribution for study sites 1 and 2 were random and the pattern for study site 3 was uniform. Random pattern would be a sign for absence of competition. On the other hand uniform pattern would indicate competition.

O trabalho objetivou identificar as espécies de abelhas sem ferrão (Hymenoptera, Apidae, Apini, Meliponina) presentes em três áreas de cerrado no Maranhão, nordeste do Brasil, por meio do levantamento de seus ninhos. Também foi objetivo do trabalho identificar e caracterizar os substratos vegetais utilizados como locais de nidificação. Pretendeu-se averiguar a abundância e a distribuição espacial de ninhos, bem como padrões de uso dos substratos para nidificação. Foram encontrados 73 ninhos pertencentes a 15 espécies. As espécies mais abundantes foram Partamona chapadicola Pedro & Camargo, 2003 (34,25%) e Oxytrigona sp. 2 (20,55%). Identificaramse 11 espécies vegetais utilizadas para construção dos ninhos. O substrato de nidificação mais freqüente foi Qualea parviflora (Vochysiaceae), na qual encontrou-se 38,36% do total de ninhos (n=28), seguido por Salvertia convallariodora (Vochysiaceae) (n=17; 23,29%). O intervalo de confiança de 95% para o DAP situou-se entre 36,21 cm a 41,68 cm. Este intervalo representaria árvores mais velhas que teriam mais cavidades disponíveis para nidificação, o que poderia ser o caso de S. convallariodora e Q. parviflora. O padrão de dispersão dos substratos com ninhos mostrou-se aleatório nas áreas 1 e 2 e uniforme na área 3. Padrões de distribuição aleatórios seriam um indício da ausência de competição e padrões uniformes indicariam competição.