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In Brazil, acerola trees infested by Meloidogyne enterolobii present lower yield and fruit quality. The use of rootstocks resistant to this pathogen is one of the alternatives to overcome this problem. This study aimed to assess the reaction of 22 acerola accessions to M. enterolobii, aiming to identify at least one resistant rootstock. The experiment was carried out in a randomized block design with 10 replications and each plot consisting of 10 plants. Each plant was inoculated with 350 eggs and second-stage juveniles of M. enterolobii, with the gall index (GI) and reproduction factor (RF) being determined after 90 days. The variables were analyzed using the mixed model methodology (REML/BLUP). The accessions ACO-13, ACO-14, ACO-18, and BRS Apodi stood out with four to six plants showing resistance reaction to the root-knot nematode, but the assessment of accessions should be performed under a higher density inoculum and longer time. RESUMO No Brasil, as aceroleiras, quando infectadas por Meloidogyne enterolobii, apresentam redução na produtividade e na qualidade dos frutos. Uma das alternativas para solucionar este problema é a utilização de porta-enxerto resistente a esse patógeno. O objetivo deste trabalho foi avaliar a reação de 22 acessos de aceroleira a M. enterolobii, visando identificar, pelo menos, um porta-enxerto resistente. O experimento foi conduzido em blocos ao acaso, com 10 repetições, sendo cada parcela formada por 10 plantas. Cada planta foi inoculada com 350 ovos mais juvenis de segundo estádio de M. enterolobii e, após 90 dias, foram determinados o índice de galhas (IG) e o fator de reprodução (FR). As variáveis foram analisadas pela metodologia de modelos mistos (REML/BLUP). Com base nas duas variáveis avaliadas, destacaram-se os acessos, ACO-13, ACO-14, ACO-18 e BRS Apodi com quatro a seis plantas com reação de resistência ao nematoide-das-galhas, mas a avaliação dos acessos deve ser feita sob maiores doses de inóculo e por tempo mais longo.

Biological control is an environmentally safe alternative in the management of nematodes. The selection of new biocontrol agents has focused on the potential of Bacillus species in in vitro and in vivo studies. In this study, twenty-three local Bacillus isolates were characterised and evaluated for metabolisable carbon source, secondary metabolite production and nematicidal action. The in vitro antagonism studies were evaluated after direct confrontation between infecting juveniles of M. enterolobii and bacterial isolates. In a greenhouse, nematicidal activity was evaluated 51 days after nematode inoculation in melon plants previously inoculated with the bacteria and cultivated in pots. The numbers of egg masses, galls, J2 and eggs in the root, J2 in the soil, the reproduction factor and the biomass yield of the plants were evaluated. From the results obtained in the laboratory experiments, it was observed that five carbon sources (D-glucose, N-acetyl-glucosamine, D-maltose, malic acid and trisodium citrate) were common to all isolates, with variation in the production of secondary metabolites. The sum of nematostatic and nematicidal effects was above 90%. In the pot experiment, a significant reduction in the number of galls was observed with the treatments LCB 03, LCB 40, LCB 45, LCB 47, LCB 51, LCB 56 and LCB 5(3) and there was no increase in plant biomass. Root protection may be associated with effective colonisation through biofilm formation and the action of metabolites with nematicide and disorientation action. However, it is necessary to carry out further studies. Made available in DSpace on 2022-05-11T11:13:33Z (GMT). No. of bitstreams: 1 Melao-Fungo-para-controle-biologico-2022.pdf: 5957977 bytes, checksum: 3573acb8639845fa39fede25201f01fb (MD5) Previous issue date: 2022

RESUMO A meloidoginose da alface interfere negativamente no desenvolvimento da planta, o que reduz a produtividade da cultura. O objetivo desse trabalho foi identificar espécies de Meloidogyne em áreas de cultivo de alface localizadas na região Agreste do estado de Alagoas. Foram realizadas coletas de solo rizosférico e de raízes totalizando 23 amostras, provenientes de sete municípios. As raízes com sintomas de meloidoginose foram cortadas e incorporadas, juntamente com o solo rizosférico, a tomateiros Santa Cruz cv. Kada Gigante, previamente cultivados em vasos contendo solo esterilizado e mantidos sob condições de telado. A identificação das espécies de Meloidogyne foi realizada por meio da análise do perfil da isoenzima esterase. As espécies de M. incognita fenótipos I1 e I2 e de M. javanica fenótipo J3 foram detectadas em 20 e em três áreas, respectivamente. ABSTRACT Lettuce root-knot negatively influences the plant development, reducing the crop yield. The objective of this study was to identify Meloidogyne species that occur in lettuce cultivation areas in the “Agreste” region of Alagoas State, Brazil. Sample collection was performed from the rhizosphere soil and roots, totaling 23 samples from seven municipalities. Roots exhibiting symptoms of root-knot were harvested and incorporated with the rhizosphere soil in tomato plants “Santa Cruz” cv. ‘Kada Gigante’ previously grown in pots containing sterile soil and kept under greenhouse conditions. Meloidogyne species were identified based on esterase isozyme analysis. Meloidogyne incognita phenotypes I1 and I2 and M. javanica phenotype J3 were detected in 20 and three areas, respectively.

As the most abundant animals on earth, nematodes are a dominant component of the soil community. They play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns., This research was supported by a grant from DOB Ecology to T.W.C., a grant from the Netherlands Organization for Scientific Research (grant 016.Veni.181.078) to S.G., grants from NSF (OPP 1115245, 1341736, 0840979) to B.J.A., by a Ramon y Cajal fellow award (RYC-2016-19939) to R.C.H., a grant from UNEP & Global Environment Facility to J.E.C., grants from NERC’s Soil Security Programme to R.D.B. (NE/M017028/1) T.C. (NE/M017036/1), a grant from FAPEMIG/FAPESP/VALE S.A.(CRA-RDP-00136-10) to L.B.C., through the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) awarded to S.R.C., a grant from CNPq PROTAX (562346/2010-4) to J.M.d.C.C., a grant from DFG (CRC990) to V.K. and S.S., a grant from the MSHE of Russia (AAAA-A17-117112850234-5) to A.A.K., grants from the Chinese Academy of Sciences (XDB15010402) and the National Natural Science Foundation of China (41877047) to Q.L., grants from the National Natural Science Foundation of China (31330011, 31170484) to W.L., grants from NERC (NE/ M017036/1) to M.M., grants from the Spanish Ministry of Innovation (CGL2009-14686-C02-01/02, CGL2013- 43675-P) to J.A.R.M., grant from the Spanish Ministry of Innovation (RYC-2016-19939) to R.C.H., grants from NSF (DEB-0450537, DEB-1145440) to P.M., T.O.P. and K. Powers, grants from the German Academic Exchange Service (PKZ 91540366) and NAFOSTED (106.05–2017.330) to T.A.D.N., by an ARC Discovery project (DP150104199) to U.N.N., by the National Key Research and Development Program of China (2016YFC0502101) and the National Natural Science Foundation of China (31370632) to K. Pan, a ERC Research Council Advanced grant (ERC-Adv 323020 SPECIALS) to W.H.v.d.P, a grant from the Natural Environment Research Council (NERC) to D.G.W., a grant from BAPHIQ (106AS-9.5.1-BQ-B3) to J.-i.Y., a grant from the Russian Foundation for Basic Research (18-29-05076) to A.V.T. The James Hutton Institute receives financial support from the Scottish Government Rural and Environment Science and Analytical Services (RESAS) division. Investigations in Northwest Russia were carried out under state order for IB KarRC RAS and are partially supported by the Russian Foundation for Basic Research (18-34-00849).

Meloidogyne enterolobii (syn. M. mayaguensis) has been reported to cause severe damage in commercial guava orchards and other plants in Central and South American countries. Considering the risk of introduction and dissemination of this pest in the European region, M. enterolobii was placed on the EPPO A2 list in 2010. The use of non-host fruit species is a recommended strategy to manage root-knot nematodes in infested guava orchards. This study screened 89 plant genotypes from 25 fruit plants of economic importance, plus two susceptible controls (guava and tomato) for its host status to M. enterolobii. Three to eight months after inoculation, nematode reproduction factor (RF) was used to characterize host suitability of fruit crops to this nematode. Ten banana genotypes, six Barbados cherries, one fig, two grape rootstocks and six melons were rated as good hosts for this nematode. Sixteen fruit plants behaved either as non-hosts or poor hosts to M. enterolobii, including assai, atemoya, avocado, cashew nut, citrus, coconut, grape, jabuticaba, mango, mulberry, papaya, passion fruit, sapodilla, soursop, starfruit and strawberry. For the future, field experiments in areas infested by this nematode are essential to confirm the greenhouse results. These non-host fruit species can replace in the future eradicated guava trees in fields severely infested by this nematode and become an economic option for growers where M. enterolobii is considered a serious problem.

Meloidogyne enterolobii associated with Fusarium solani causes the guava decay, which is the main factor of yield loss in guava crops and limits guava production in Brazil. Therefore, searching for guava genotypes (Psidium spp.) with resistance to M. enterolobii is important to control this root-knot nematode. The objective of the present work was to evaluate the reaction of Psidium spp. accessions from the Germplasm Bank of the Bahia State University (UNEB) to different levels of inoculation with M. enterolobii. Guava seedlings were inoculated with 600, 1,600, and 2,000 eggs + J2 second stage juveniles of M. enterolobii and the root fresh weight, total number of eggs (TNE), and reproduction factor (RF) were evaluated. The results were subjected to ANOVA and means were clustered using the Scott-Knott test at 5% probability. The diversity of accessions was estimated using the Tocher's clustering and UPGMA methods. The nematode RF reduced in some accessions with increasing inoculation levels of the nematode. However, the RF increased in some accessions with high levels of inoculation. Plants of the Y50 accession were immune or resistant to M. enterolobii, indicating variability of reaction of plants to the nematode within the Psidium genus. The resistance of Psidium accessions to M. enterolobii needs to be measured with different inoculation levels to verify the existence of false-positive results, since the evaluated accessions, including the Paluma cultivar, presented distinct reactions regarding RF in the three levels of inoculation used. RESUMO Meloidogyne enterolobii, juntamente com Fusarium solani, causam o declínio da goiabeira que é a principal causa de perdas na produção de goiaba, limitando o cultivo em todo o Brasil. Portanto, a busca por genótipos dentro do gênero Psidium com resistência a M. enterolobii é muito importante para o controle deste nematoide. Assim, o presente trabalho teve como objetivo avaliar a reação de acessos de Psidium spp., pertencentes ao Banco de Germoplasma da Universidade do Estado da Bahia (UNEB), a diferentes níveis de inóculo de M. enterolobii. Mudas de goiabeira foram inoculadas com 600, 1.600 e 2.000 ovos + J2 (juvenis de segundo estádio) de M. enterolobii/planta e avaliados a massa fresca de raízes, o número total de ovos (NTO) e o fator de reprodução (FR). A análise de variância foi feita e o agrupamento de médias foi realizado pelo teste Scott-Knott a 5% de probabilidade. A diversidade dos acessos foi estimada pelo agrupamento de Tocher e UPGMA. O FR do nematoide apresentou redução em alguns acessos à medida que os níveis de inóculo aumentaram, contudo, em alguns acessos, nos maiores níveis, o FR aumentou. O acesso Y50 teve plantas imunes e resistentes a M. enterolobii, demostrando que ocorre variabilidade na reação ao nematoide dentro do gênero Psidium. A resistência de acessos de Psidium a M. enterolobii deve ser mensurada em diferentes níveis de inóculo de modo a permitir avaliar a existência de falsos-positivos nesses acessos uma vez que há reação distinta dos acessos avaliados quanto à reprodução do nematoide nos três níveis de inóculo usados, inclusive na cv. Paluma.

Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, few quantitative, spatially explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here we use 6,759 georeferenced samples to generate a mechanistic understanding of the patterns of the global abundance of nematodes in the soil and the composition of their functional groups. The resulting maps show that 4.4 ± 0.64 × 1020 nematodes (with a total biomass of approximately 0.3 gigatonnes) inhabit surface soils across the world, with higher abundances in sub-Arctic regions (38% of total) than in temperate (24%) or tropical (21%) regions. Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes in global biogeochemical models and will enable the prediction of elemental cycling under current and future climate scenarios., This research was supported by a grant from DOB Ecology to T.W.C., a grant from the Netherlands Organization for Scientific Research (grant 016.Veni.181.078) to S.G., grants from NSF (OPP 1115245, 1341736, 0840979) to B.J.A., by a Ramon y Cajal fellow award (RYC-2016-19939) to R.C.H., a grant from UNEP & Global Environment Facility to J.E.C., a grant from NERC (NE/M017036/1) to T.C., a grant from FAPEMIG/FAPESP/VALE S.A.(CRA-RDP-00136-10) to L.B.C., through the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) awarded to S.R.C., a grant from CNPq PROTAX (562346/2010-4) to J.M.d.C.C., a grant from DFG (CRC990) to V.K. and S.S., a grant from the MSHE of Russia (AAAA-A17-117112850234-5) to A.A.K., grants from the Chinese Academy of Sciences (XDB15010402) and the National Natural Science Foundation of China (41877047) to Q.L., grants from the National Natural Science Foundation of China (31330011, 31170484) to W.L., grants from NERC (NE/M017036/1) to M.M., grants from the Spanish Ministry of Innovation (CGL2009-14686-C02-01/ 02, CGL2013-43675-P) to J.A.R.M., grants from NSF (DEB-0450537, DEB-1145440) to P.M., T.O.P. and K. Powers, grants from the German Academic Exchange Service (PKZ 91540366) and NAFOSTED (106.05 – 2017.330) to T.A.D.N., by an ARC Discovery project (DP150104199) to U.N.N., by the National Key Research and Development Program of China (2016YFC0502101) and the National Natural Science Foundation of China (31370632) to K. Pan, a grant from the Natural Environment Research Council (NERC) to D.G.W., a grant from BAPHIQ (106AS-9.5.1-BQ-B3) J.-i.Y. The James Hutton Institute receives financial support from the Scottish Government Rural and Environment Science and Analytical Services (RESAS) division. Investigations in northwest Russia were carried out under state order for IB KarRC RAS and are partially supported by the Russian Foundation for Basic Research (18-34-00849). We thank E. Clark and A. Orgiazzi for review of the manuscript; and R. Bouharroud, Z. Ferji, L. Jackson and E. Mzough for providing data.

RESUMO A utilização de material propagativo sadio constitui importante medida de controle para os nematoides da bananeira (Musa spp.), pois, assim, evita-se a introdução desses patógenos em áreas isentas. O objetivo deste trabalho foi avaliar o efeito da aplicação de Bacillus subtilis (Nemathel®) no tratamento de mudas, do tipo chifre, de bananeira subgrupo Terra cv. Comprida, infectadas por uma população mista com Radopholus similis, Meloidogyne spp., Pratylenchus spp. e Helicotylenchus spp. Foram testadas diferentes doses do produto (50; 100; 150; 200 e 250 mL/10 L de água) mais as testemunhas positiva (nematicida) e negativa (água). As mudas foram imersas em cada um dos tratamentos por 30 minutos e plantadas em vasos com solo esterilizado. A avaliação foi realizada após quatro meses e as doses de 200 e 250 mL do produto por 10 L de água proporcionaram as maiores reduções das populações dos nematoides em raízes e rizomas. ABSTRACT The use of healthy propagative plant material is an important management method for nematodes in banana crops (Musa spp.), once it prevents the introduction of nematodes in non-infested areas. The aim of this work was to evaluate the effect of the bio-nematicide Nemathel® (Bacillus subtilis) on Terra banana plantlets cv. Comprida infected with a mixed population of Radopholus similis, Meloidogyne spp., Pratylenchus spp., and Helicotylenchus spp. Different doses of Nemathel® (50, 100, 150, 200, and 250 mL/10 L water) were tested in addition to the positive (nematicide) and negative (water) treatments. The plantlets were immersed in each treatment for 30 min and subsequently, planted in pots containing sterilized soil in greenhouse. The evaluation was performed four months later. Dosages of 200 and 250 mL of Nemathel®/10 L in water showed the greatest reduction of nematode populations in roots and rhizomes.

The objective of this study was to accomplish a survey on populations of Meloidogyne and Pratylenchus species in sugarcane farming areas in the state of Alagoas, Brazil. Twenty samples of soil and roots were processed to extract and quantify nematodes; however, the identification of Meloidogyne species was performed using only 12 samples. Pratylenchus spp. were reported at moderate population levels of 68-1556 specimens 50g-1 of roots and 2-298 specimens 100cm-3 of soil in twenty analyzed samples. For Meloidogyne spp., these values were of 12-487 specimens 50g-1 of roots and 0-140 specimens 100cm-3 of soil. Based on electrophoresis of esterase isozymes, M. incognita was reported to be the most frequent species, followed by M. javanica and M. arenaria. Pratylenchus species identified through morphometrical and morphological characteristics were P. zeae and P. brachyurus , with predominance for the first species. No significant correlation (P≤0.05) were reported between nematode populations and sugarcane cropping systems. RESUMO: O objetivo deste trabalho foi realizar um levantamento de espécies de Meloidogyne e de Pratylenchus existentes em áreas de cultivo de cana-de-açúcar, no estado de Alagoas. Vinte amostras de solo e raízes foram processadas para a extração e quantificação, sendo a identificação das espécies de Meloidogyne realizada em 12 amostras. Detectou-se a presença de Pratylenchus spp. em níveis populacionais médios de 68-1556 espécimes 50g-1 de raízes e 2-298 100cm-3 de solo, em todas as amostras. Para Meloidogyne spp., esses valores foram de 12-487 50g-1 de raízes e 0-140 100cm-3 de solo. Com base na eletroforese da isoenzima esterase, M. incognita foi a espécie mais frequente, seguida por M. javanica e M. arenaria . As espécies de Pratylenchus identificadas pelas características morfológicas e morfométricas, foram P. zeae e P. brachyurus , com predomínio da primeira espécie. Não houve correlações significativas (P≤0,05) entre as populações de nematoides e as características dos sistemas de cultivo de cana-de-açúcar.

No Brasil, Meloidogyne enterolobii vem causando perdas significativas na produção de goiabeiras e, no submédio do Vale do São Francisco, por exemplo, o impacto negativo decorrente da infecção e morte de goiabeiras tem refletido diretamente na qualidade de vida dos agricultores. Até o momento, não existem métodos de controle efetivos: os nematicidas avaliados experimentalmente não têm sido eficientes e não há produtos registrados no Ministério da Agricultura, Pecuária e Abastecimento para aplicação em goiabeiras. Assim, há necessidade de realizar pesquisa básica nesta área. A prospecção de proteínas relacionadas com a resistência em espécies resistentes pode ser uma alternativa para o desenvolvimento de medidas para seu controle. Para isso, foram realizados ensaios biológicos de toxicidade para a análise do efeito de extratos proteicos de amendoim sobre o desenvolvimento, a capacidade infectiva e atividade de enzimas proteolíticas de M. enterolobii visando à identificação de proteínas com potencial para controle desse nematoide. Os resultados obtidos indicaram que o extrato proteico total de amostras de raízes de plantas de amendoim inoculadas não tem efeito sobre as três características supracitadas. Sendo assim, são necessários estudos dessa natureza com outras espécies resistentes ao patógeno visando à identificação de proteínas que apresentem potencial para o seu controle. In several regions of the country, including the São Francisco Valley, Meloidogyne enterolobii has caused significant losses in the production of guava, reflecting negatively on life quality of farmers in the region. To date, there is no effective control method, nematicides have been evaluated experimentally and have not been efficient in their control and there are no products registered with the Ministry of Agriculture, Livestock and Supply for use in guava. Therefore, there is a critical need for basic research on this area and the prospection of proteins related to resistance to M. enterolobii in nematode resistant species may be an alternative for the development of control measures. For this purpose, biological assays of toxicity were performed to analyze the effect of peanut protein extracts on the development, infective capacity and activity of proteolytic enzymes of M. enterolobii for the identification of proteins with potential to control this pest. Results showed that total protein extracts from peanut root samples inoculated with M. enterolobii has no effect on the three characteristics evaluated. Thus, similar studies with other species resistant to the pathogen are needed to identify proteins with potential to control M. enterolobii.

The aim of this study was to evaluate the performance of progenies from Citrullus lanatus var. lanatus (cultivated watermelons) when crossed with progenies from C. lanatus var. citroides (fodder watermelon with a historic of resistance to the nematode Meloidogyne enterolobii). The parents and their F1s were evaluated for resistance to this nematode. In the initial stages of eleven treatments, watermelon seedlings plantlets were transplanted to plastic bags of six kilograms once the first leaves developed. Ten inoculated plants with 5,200 eggs in the soil near the stem of the plant and four non-inoculated ones were used in each treatment, in a complete block design. Sixty-two days after sowing, the following characteristics were evaluated: the length of the aerial part of the plant (LAP, in m), fresh mass of the aerial part (FMAP, in g), root fresh mass (RFM, in g), egg number (EN) and reproduction factor (RF). A comparison between the averages of inoculated and non-inoculated plants was performed using Scott-Knott test at 5% and the diallelic analysis was performed using the GENES program. The morphological characteristics did not allow for the identification of the parent plants or the F1s with respect to nematode resistance, but the variables EN and RF were useful for such identification. The analyses of the general and specific combining abilities indicate highly significant effects with respect to this resistance, showing additive gene effects as well as dominance and epistatic gene effects, allowing for identification of parents and F1s that can be used in watermelon breeding programs to improve resistance to the M. enterolobii. RESUMO: O objetivo deste estudo foi avaliar o desempenho de progênies de melancia provenientes de Citrullus lanatus var. lanatus (melancias cultivadas) quando cruzadas com progênies provenientes de C. lanatus var. citroides (melancias forrageiras com histórico de resistência ao nematoide Meloidogyne enterolobii). Os parentais e seus F1s foram avaliados quanto à reação a esse nematoide. Mudas de melancia de onze tratamentos no estádio inicial, com a primeira folha definitiva recém desenvolvida foram plantadas em sacos plásticos de seis quilogramas. Utilizou-se dez plantas inoculadas com 5.200 ovos próximo ao colo da planta e quatro não inoculadas em cada tratamento em um delineamento inteiramente casualizado. Após 62 dias foram avaliados os seguintes caracteres: comprimento da parte aérea (CPA, em m), massa fresca da parte aérea (MFPA, em g), massa fresca de raiz (MFR, em g), número de ovos (NO) e o fator de reprodução (FR). A comparação das médias das plantas inoculadas e não inoculadas foi feita usando o teste de Scott-Knott ao nível de 5%. A análise dialélica foi realizada utilizando-se o programa GENES. Os caracteres morfológicos não permitiram identificar as plantas dos parentais e dos F1s quanto à reação ao nematóide, porém, as variáveis NO e FR foram eficientes nessa identificação. A análise das capacidades geral e específica de combinação indicou efeitos altamente significativos quanto a essa reação, mostrando efeitos gênicos aditivos e também efeitos de dominância e epistáticos, permitindo identificar pais e F1s para serem usados em programas de melhoramento de melancia para resistência ao M. enterolobii.

The dyes used for staining nematode egg masses and eggs can cause environmental hazards and human health concerns. The aim of this study was to evaluate different artificial food dyes, as a replacement for acid fuchsin and phloxine B, for staining eggs and egg masses of Meloidogyne javanica from infected tomato plants. Five different combinations of dyes were tested at five concentrations. For control treatments, infected roots were stained with acid fuchsin and phloxine B for coloring eggs and egg masses, respectively. Egg staining with the dyes ponceau 4R with red 40 and ponceau 4R with brilliant blue, at the concentration of 4%, showed results similar to those obtained with acid fuchsin. However, egg masses were effectively stained with ponceau 4R food dyes with red 40 and with ponceau 4R with brilliant blue at all tested concentrations. Ponceau food coloring dyes gave a good contrast for nematode egg masses and egg counting, do not present human health and environmental pollution problems, and can be reused, with less waste being generated in the laboratory. These dyes are low-cost products that are available at most supermarkets, and can efficiently substitute acid fuchsin and phloxine B for staining eggs and egg masses of M. javanica.

O objetivo deste trabalho foi caracterizar 119 acessos de goiabeira e 40 acessos de aracazeiro identificados em 35 ecorregioes brasileiras, de acordo com descritores da International Union for the Protection of New Varieties of Plants (UPOV). A maioria dos acessos de aracazeiro apresentou grandes espacos entre as nervuras da folha, enquanto os de goiabeira apresentaram espacos pequenos. Os frutos de aracazeiro foram classificados como pequenos, enquanto os de goiabeira apresentaram tamanho de medio a grande. A maioria dos acessos de aracazeiro (91%) apresentou cor branca para a polpa do fruto, enquanto 58% dos de goiabeira apresentaram cor de rosa-claro a rosa-escuro. As diferencas nos frutos entre Psidium selvagens e domesticados indicam que os frutos foram os mais alterados pela selecao artificial.

The guava decline, a complex disease caused by the interaction between Meloidogyne enterolobii and Fusarium solani, has caused damage to production and unviable guava producing areas in the Lower Basin of the São Francisco Valley. The management of this disease is difficult due to the facts that cultivated plants are susceptible to nematodes, nematicides have no effective control, and the use of fungicides to control Fusarium still has not been evaluated. However, some Psidium genotypes, such as the araçazeiros, show resistance to the nematodes, and therefore decline resistance. The objective of this study was to evaluate the interaction between genotypes of Psidium spp. and M. enterolobii to identify resistant plants. Three araçazeiro genotypes from the states of São Paulo and Paraná were artificially inoculated with M. enterolobii and compared with the species P. guajava cultivar Paluma, which is a commercial cultivar susceptible to root-knot nematode. All araçazeiro genotypes evaluated were resistant to the disease, with low reproduction factor (0.000 to 0.004) compared to cultivar Paluma (FR = 1,610). These results demonstrate that the araçazeiro genotypes have the potential to be used in the development of rootstocks resistant to guava decline., O declínio da goiabeira, doença complexa causada pela interação entre Meloidogyne enterolobii e Fusarium solani, vem causando danos à produção e tem inviabilizado áreas de cultivo desta frutífera no Submédio do Vale do São Francisco. O manejo desta doença é difícil, pois as cultivares plantadas são suscetíveis ao nematoide, os nematicidas não têm apresentado eficiência e o uso de fungicidas para controle da fusariose, ainda, não foi avaliado. Contudo, alguns genótipos de Psidium, como araçazeiros, apresentam resistência a esse nematoide e, por conseguinte, resistência ao declínio. O objetivo deste trabalho foi avaliar a interação entre genótipos de Psidium spp. e M. enterolobii, visando a identificação de plantas resistentes. Foram utilizados três genótipos de araçazeiro provenientes dos estados de São Paulo e Paraná que foram inoculados artificialmente com M. enterolobii e comparadas com P. guajava ‘Paluma’, cultivar comercial suscetível ao nematoide-das-galhas. Todas as espécies de araçazeiros avaliadas se mostraram resistentes à doença, apresentando baixo fator de reprodução (0,000 a 0,004) em comparação com a cultivar Paluma (FR = 1,610). Esses resultados demonstram que os araçazeiros avaliados têm potencial para serem utilizadas no desenvolvimento de porta-enxertos resistentes ao declínio da goiabeira.

The root-knot nematode, Meloidogyne mayaguensis, causes serious economic loss to guava plantation in Brazil. Fungi associated with eggs of M. mayaguensis in Brazilian soil have not been studied yet, but this knowledge could form the basis for future field studies on biological control of this nematode. The egg parasitic fungi, Pochonia chlamydosporia var. chlamydosporia, P.chlamydosporia var. catenulata and Lecanicillium psalliotae, were isolated from M. mayaguensis eggs and analyzed based on their cultural and morphological characteristics. The optimum temperature for growth and spore production ranged between 24 and 28ºC for P. chlamydosporia isolates. For the isolate of L. psalliotae, the best growth was at 30ºC. In solid state fermentation, P. chlamydosporia isolates produced between 3.5 and 5.2 x 10(6) chlamydospores per g of colonized substrate, whereas L. psalliotae isolate produced 8.5 x 10(8) conidia per g of colonized substrate. Future studies are required to clarify the potential of these fungi as biological control agents of M. mayaguensis. O nematóide das galhas, Meloidogyne mayaguensis, causa sérias perdas econômicas em plantações de goiaba no Brasil. Fungos parasitas de ovos de M. mayaguensis ainda não foram estudados no Brasil, mas essas informações podem servir de base para estudos futuros de controle biológico em campo. Os fungos parasitas de ovos, Pochonia chlamydosporia var. chlamydosporia, P.chlamydosporia var. catenulata e Lecanicillium psalliotae foram isolados em ovos de M. mayaguensis e analisados quanto às suas características morfológicas e culturais. Para os isolados de P. chlamydosporia a melhor temperatura para crescimento e esporulação variou entre 24 e 28 ºC. Para o isolado de L. psalliotae, a melhor temperatura para crescimento foi 30 ºC. Em estado sólido, os isolados de P. chlamydosporia produziram entre 3,5 e 5,2 x 10(6) chlamidosporos por g de substrato colonizado, enquanto que o isolado de L. psalliotae produziu 8,5 x 10(8) conídios por g de substrato colonizado. Há necessidade de estudos futuros para mostrar o potencial desses fungos como agentes de controle biológico de M. mayaguensis.

Isozymes (esterase and malate dehydrogenase), SCAR and RAPD-PCR were studied in 15 populations of three races of Meloidogyne exigua collected in coffee-producing areas in Brazil, Bolivia and Costa Rica and one population from rubber tree plantations in Brazil. This study revealed four esterase phenotypes (E1, E2, E2a, E3) and three malate dehydrogenase phenotypes (N1, N1a, N2) for M. exigua populations. The most common multi-enzyme phenotype was E2N1. The enzymatic phenotypes do not separate M. exigua races. Sixteen populations of M. exigua were tested in Multiplex PCR using SCAR primers ex-D15F/R that allowed the identification of all M. exigua populations. Phylogenetic analyses showed high intraspecific polymorphism (25.9-59.6%) for all M. exigua studied. However, all populations clustered together with 100% bootstrap support, thereby demonstrating the consistency of species identification. In general, no correlation was found between enzymatic profile, race and genetic polymorphism of the studied populations.

Meloidogyne enterolobii has severely compromised the main guava producing regions in Brazil, thereby stimulating the development of resistant varieties for efficient management of this nematode. This study aimed to assess the penetration, development, reproduction, and induced cellular responses of M. enterolobii in roots of four species of the genus Psidium (P. guajava‘Paluma’, P. guineense, P. cattleyanum, and P. friedrichstalianum) from the Active Germplasm Bank (BAG) of the Center for Agricultural Research of the Semi-arid Tropics (Embrapa Semi-arid) located in Petrolina, PE, Brazil. Three experiments were carried out to assess the penetration, development, and reproduction of the nematode and, subsequently, histological analyses were performed. Nematode penetrated indistinctly in both resistant and susceptible species, but only in ‘Paluma’ an evolution was observed from vermiform juveniles to “sausage” and globose forms in experiment 1. In experiment 2, all species presented “sausage” forms of nematode, but only in ‘Paluma’, these forms reached adult female stages. In experiment 3, only ‘Paluma’ was susceptible to M. enterolobii, with reproduction factor above unity. Histological analyses showed that, except for P. guajava, the other Psidium species presented poorly developed feeding sites at 20 days after inoculation. RESUMO A presença de Meloidogyne enterolobii nas principais regiões de cultivo de goiabeira tem comprometido severamente a produção brasileira do fruto e estimulado o desenvolvimento de variedades resistentes para manejo eficiente do nematoide. O presente estudo teve como objetivos avaliar a penetração, o desenvolvimento, a reprodução e as respostas celulares induzidas por M. enterolobii nas raízes de quatro espécies do gênero Psidium (P. guajava ‘Paluma’, P. guineense, P. cattleyanume P. friedrichstalianum), provenientes do Banco Ativo de Germoplasma (BAG) do Centro de Pesquisa Agropecuária do Trópico Semiárido (Embrapa Semiárido), localizado em Petrolina-PE. Foram realizados três experimentos para a avaliação da penetração, desenvolvimento e reprodução do nematoide, e, ao final, realizadas análises histológicas. O nematoide penetrou indistintamente nas espécies resistentes e suscetíveis, mas apenas em ‘Paluma’ houve evolução dos juvenis vermiformes para as formas salsichoides e globosas, no experimento 1. No experimento 2, em todas as espécies, havia formas salsichoides do nematoide, porém, apenas em ‘Paluma’, elas chegaram a fêmeas adultas. No experimento 3, apenas ‘Paluma’ mostrou-se suscetível a M. enterolobii com fator de reprodução maior do que 1. As análises histológicasmostraram que, ao contrário de P. guajava, as demais espécies de Psidium apresentaram sítios de alimentação pouco desenvolvidos aos 20 dias após a inoculação.

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O objetivo deste trabalho foi caracterizar 119 acessos de goiabeira e 40 acessos de araçazeiro identificados em 35 ecorregiões brasileiras, de acordo com descritores da International Union for the Protection of New Varieties of Plants (UPOV). A maioria dos acessos de araçazeiro apresentou grandes espaços entre as nervuras da folha, enquanto os de goiabeira apresentaram espaços pequenos. Os frutos de araçazeiro foram classificados como pequenos, enquanto os de goiabeira apresentaram tamanho de médio a grande. A maioria dos acessos de araçazeiro (91%) apresentou cor branca para a polpa do fruto, enquanto 58% dos de goiabeira apresentaram cor de rosa-claro a rosa-escuro. As diferenças nos frutos entre Psidium selvagens e domesticados indicam que os frutos foram os mais alterados pela seleção artificial. Made available in DSpace on 2011-04-09T18:03:08Z (GMT). No. of bitstreams: 1 OPB1770.pdf: 60161 bytes, checksum: e389704b33d1f7839782ef7ef7fc9e47 (MD5) Previous issue date: 2008-05-27