No abstract

RESUMOCom a finalidade de diminuir as perdas causadas pelos nematóides do gênero Meloidogyne (Goeldi, 1887) na cultura do cafeeiro, dentre as diversas medidas de manejo, o controle biológico com o fungo Paecilomyces lilacinus (Thom., 1910) ABSTRACTIn order to reduce the losses caused by nematodes of the genus Meloidogyne (Goeldi, 1887) in coffee plantation, among several management measures, biological control with the fungus Paecilomyces lilacinus (Thom., 1910) Samson, 1974 stands out as an advantageous alternative of control, from the ecological or economy points of view. Thus, the objective of this work was to evaluate ten isolates of Paecilomyces lilacinus in the control of Meloidogyne paranaensis in coffee trees (Coffea arabica L.) cv. Icatú, in greenhouse conditions. In the first experiment, the coffee seedlings were transplanted to substrate where tomato plants were previously cultivated, for M. paranaensis multiplication. The soil was mixed with 50 g rice colonized with ten isolates of P. lilacinus. In the second experiment, coffee seedlings were transplanted to substrate (1 sand: 1 dirt) with 50 g rice colonized with the isolates of P. lilacinus. Then, the seedlings were inoculated with suspension of ±5000 eggs of M. paranaensis. In the two experiments, a new application was made with 50 g of the isolates after fifteen days. The design was completely randomized with twelve treatments and ten replicates. After 90 they days were evaluated. The isolated of P. lilacinus did not affect the diameter of the coffee stalk. In the first experiment, the isolates Pae 22, 24, and 28 promoted the growth of the seedlings, all of the isolates reduced the population of eggs in the root system, and the isolates Pae 3 and 12 reduced the population of J2 of M. paranaensis in the soil. In the second experiment, the isolates Pae 3, 10, 12, and 13 favored the growth of the plants but reduced the weight of the fresh roots, all of the isolates reduced the population of J2 in the soil, and the isolates Pae 3, 10, 13, 18, 22, and 24 reduced the malformations caused by M. paranaensis roots.

This study assessed the importance of stratified soil sampling on the detection (and therefore the distribution) of nematode communities and the differentiation of ecosystems by collecting stratified soil samples at intervals of 10 cm and non-stratified samples from 0 to 30 cm in two soil management systems (no-tillage and conventional tillage) and in a native forest fragment. The nematode frequency and prominence values were obtained after extraction by successive screening operations, sugar floatation clarification and the identification of nematodes to the genus level. The nematode communities were compared two-by-two based on Sorensen's community coefficient (CC) and the percentage similarity (PS). Relative abundances of functional guilds were subjected to a principal component analysis (PCA) and classified in dendrograms. Thirty-two edaphic nematode genera were found, and the nematode communities sampled on a non-stratified basis in the soil profile exhibited a high level of similarity because they could not be accurately characterized. Genera with low abundances were not detected. In the stratified samples, we were able to classify and group the nematodes present at different depths, mainly from 0 to 10 cm. Stratified soil sampling allowed a more accurate characterization and greater differentiation of nematode communities, identifying taxa that occurred at lower abundance levels, irrespective of frequency. Key words: Bioindicators. Free-living nematodes. Nematofauna. Similarity. Vertical distribution. ResumoCom o objetivo de avaliar a importância da amostragem estratificada de solos na detecção (assim como na distribuição) de comunidades de nematoides e na diferenciação de ecossistemas, amostras de solo estratificadas em intervalos de 10 cm e não estratificadas de 0 a 30 cm foram coletadas em dois sistemas de prepare do solo (plantio direto e preparo convencional), e em um fragmento de floresta nativa. Após extração por peneiramento sucessivo, clarificação por flotação em sacarose e identificação dos nematoides até nível de gênero, a frequência e proeminência dos nematoides foram obtidas. As comunidades de nematoides foram comparadas duas a duas, baseadas no Coeficiente de comunidade de Sorensen e na Similaridade percentual (PS). Abundâncias relativas das guildas funcionais foram submetidas à Análise de componentes principais (PCA) e classificadas em dendrogramas. Trinta e dois gêneros de nematoides edáficos foram encontrados e as comunidades de nematoides amostradas de forma não estratificada no perfil do solo apresentaram um maior nível de similaridade entre si, pois não foram corretamente caracterizadas e os gêneros com baixa abundância não foram detectados. Nas amostras estratificadas, foi possível classificar e agrupar os nematoides presentes em diferentes profundidades, principalmente

Soil nematodes are sensitive to human intervention and widely used as biological indicators of disruptions and alterations in soil quality. The aim of this work was to identify nematodes that are good biological indicators in maize crops under different management systems, and to establish the impact levels of these systems. Soil samples were collected over a 3-year period at a depth of 0.0-0.3 m in areas under six different management systems for maize (Zea mays) monoculture, and intercropped maize and Canavalia ensiformis. Six areas of native vegetation were also assessed to provide a reference for ecological balance. After identification and counting, nematode communities were characterised according to abundance (total and relative), diversity (identified genera and diversity indexes), trophic structure and ecological maturity (disturbance indexes). Nematodes proved to be good ecological indicators, responding to the systems employed. Intercropping maize and Canavalia ensiformis in at least one assessment year reduced disruption and increased nematode diversity, which were both verified based on specific indexes. It was also observed that the maize monoculture increased disruption leading to a drop in nematode fauna diversity and an increase in the incidence of plant-feeding nematodes.

Nematodes play different ecological roles in soil, interfering with feed rates by regulating microbiota and the development of plant diseases. The natural characteristics of an environment as well as the agricultural process alter the distribution of these organisms. The objective of this study is to assess the effect of continuous sugarcane crop time on free-living and plant-parasitic nematodes in soils with different textures. Soil samples were collected from areas of native vegetation and agricultural plots cropped with sugarcane in two municipalities in the state of Parana, Brazil (soil with medium-textured and clay-textured), with subsequent extraction and identification of trophic groups and genus of plant-parasitic nematodes. The nematodes structure was most severely affected by sugarcane crop time, with an increase in the plant-parasitic nematodes abundance over time. Agricultural plots were dominated by Pratylenchus sp. and Helicotylenchus sp., and communities in areas of native vegetation were dominated by free-living nematodes, especially bacterial-feeding, with an incidence of carnivorous/omnivorous nematodes and Mesocriconema sp.Key words: bioindicators, Helicotylenchus, Mesocriconema, monoculture, Pratylenchus Resposta de nematoides de vida livre e fitoparasitas ao cultivo de cana-de-açúcar em dois solos RESUMOOs nematoides desempenham diversas funções ecológicas no solo interferindo na taxa de rações, regulando a microbiota e o desenvolvimento de doenças em plantas. As características naturais de um ambiente, tal como também o processo agrícola, alteram a distribuição desses organismos. Assim, o objetivo deste trabalho foi avaliar o efeito do tempo de cultivo contínuo com cana-de-açúcar sobre nematoides fitoparasitas e de vida livre em solos com diferentes texturas. Foram coletadas amostras de solo em áreas de vegetação nativa e parcelas agrícolas cultivadas com cana-de-açúcar em dois municípios no estado do Paraná, Brasil (solo com textura média e textura agilosa), com posterior extração e identificação dos grupos tróficos e gêneros de nematoides fitoparasitas. O tempo de cultivo com cana-de-açúcar afetou mais severamente a estrutura das comunidades, ocorrendo aumento na abundância de nematoides fitoparasitas com o tempo. As parcelas agrícolas foram dominadas por Pratylenchus sp. e Helicotylenchus sp. e as comunidades nas áreas de vegetação nativa dominadas por nematoides de vida livre, principalmente bacteriófagos, com incidência de nematoides canívoros/onívoros e Mesocriconema sp.

The quantification of soil nematodes is of great importance for the management and evaluation of the efficiency of control methods, considering the damages caused in crops of economic interest. The present work aimed to quantify and identify plant parasitic nematodes in pasture areas in the municipality of Santo Antônio do Leverger, Mato Grosso state, Brazil. For that purpose, 25 soil and root samples were collected in four plots, consisting of the following forage grasses: Brachiaria humidicola cv. Common (Plot 1), Panicum maximum cv. Tanzania (Plot 2), Brachiaria brizantha cv. Marandu (Plot 3) and Panicum maximum cv. Massai (Plot 4). The nematode extraction from the soil and root samples was performed, followed by the quantification and identification of nematodes genera. The nematodes classified as free-living were observed in all plots, with population densities varying from 230 to 1180 specimens. The genus Pratylenchus presented the lowest population level, with 40 specimens, in the area where the Brachiaria humidicola cv. Common is cultivated. The following phytoparasitic nematodes genera were observed: Pratylenchus and Paratrichodorus associated to the Humidicola grass, and Heterodera and Criconemoides associated to the Tanzania grass.