Upland cotton (Gossypium hirsutum ) is an important fiber crop grown throughout the southern United States. Plant-pathogenic nematodes are worm-like animals that feed on the roots of most agronomic crops, including cotton. The southern root-knot nematode (Meloidogyne incognita, RKN) and the reniform nematode (Rotylenchulus reniformis, RN) cause significant yield losses in cotton every year. Current sources of resistance are effective but limited, therefore historical screenings of cotton accessions were revisited in search for novel resistance sources. None were identified but many of the screened accessions possessed markers of known root-knot nematode and reniform nematode resistance. The emerging guava root-knot nematode (Meloidogyne enterolobii, GRKN) is a risk for upland cotton production, and identifying host plant resistance would greatly reduce the yield losses for growers. Assays were conducted on the currently available RN and RKN resistance sources inoculated with GRKN. No known nematode resistance gene suppressed GRKN infection, indicating that work must be done to protect crops from the eventual discovery of GRKN in Mississippi fields. Using the same resistance sources, tests were conducted to determine if the currently available resistances to RKN and RN offer any suppression of secondary infection of non-target nematode species for resistance. This is referred to as systemic acquired resistance, which is the induction of non-specific plant defense. Assays found that early inoculation with the nematode targeted by resistance did not effect infection by a secondary nematode species.

One of the objectives of this research was to evaluate the need for an additional imidacloprid seed treatment on ThryvOn® (Bayer Crop Science®, St. Louis, MO) cotton to effectively manage tobacco thrips, Frankliniella fusca (Hinds). While evaluating thrips densities and damage ratings, ThryvOn cotton continued to display reduced damage and thrips populations than non-ThryvOn. Thrips populations and damage ratings were consistently reduced when incorporating a higher rate of imidacloprid, but they were not reduced enough to justify the higher rates of imidacloprid. Another objective of this research was to evaluate the impact of aldicarb (AgLogic Chemical®, LLC; Chapel Hill, NC) and ThryvOn on reniform nematode, Rotylenchulus reniformis (Linford & Oliveira). The impact of aldicarb and ThryvOn technology had no impact on reniform nematode densities in Mississippi cotton throughout this study. The reduced thrips populations and damage ratings provided by ThryvOn cotton has the potential to improve integrated pest management in the southern U.S.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-20T13:02:10Z No. of bitstreams: 1 Daniela Silva Salgues de Matos.pdf: 463245 bytes, checksum: 6041b12480d1db2b27dea971c15113a0 (MD5) / Made available in DSpace on 2017-02-20T13:02:10Z (GMT). No. of bitstreams: 1 Daniela Silva Salgues de Matos.pdf: 463245 bytes, checksum: 6041b12480d1db2b27dea971c15113a0 (MD5) Previous issue date: 2006-02-21 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / More than 35 species of plant parasitic nematodes are reported associated with papaya (Carica papaya) being the root-knot nematodes one of the most important. These populations occur in polyspecific communities and different densities depending on cultivars, host stress and physical, chemical and biological soil properties. The present study had the objectives of describing nematode community structure associated with papaya croping in soil infested with Meloidogyne sp. in Mamanguape, Paraíba, and evaluating number of samples and pattern for soil colllection in order to monitore Meloidogyne sp. and Rotylenchulus sp. population density in field. Samplings were carried out in three areas with different population levels of root-knot and reniform nematodes. In each area, 5,776 m2 was split in 400 (20 × 20) squares of 14.44 m2 (3.8 × 3.8 m), containing three plants. Evaluations for nematode community structure based upon nematode community indexes: maturity index (MI), plant parasitic index (PPI) and modified maturityindex (MMI), and nematode trophic group ratios. It was simulated collecting samples in “X”, diamond, parallel lines, parallel rows, inverted “V”, zig-zag, inverted “W”, “degree”, “S”, randomly and in ordinary walking in order to select diagram pattern for sampling. For sample size evaluation, all diagram patterns were used changing the number of samples (40, 30 e 20) in each area. Population density (specimes/300cm3 soil) of both nematodes were predicted according to size and diagram of sampling and compared through Kruskal-Wallis test at 5% probability level. In areas 1 and 3 there was predominance of plant parasitic nematodes, 43.84 and 39.95 % respectively, especially Rotylenchulus sp. In area 2, Meloidogyne was the taxon of highest dominance among the plant parasitic nematodes. Inthe three areas MI and MMI were high (> 30%) and PPI ranged from 20.95 to 32.88%. Twenty samples per area were indicated for both nematode genus, being recommended to collect the samples randomly, in parallel bars, or in diamond for monitoring Meloidogyne sp. and in parallel bars or parallel lines for Rotylenchulus sp / Mais de 35 espécies de fitonematóides são relatadas na rizosfera de mamoeiro (Carica papaya), com destaque para os nematóides das galhas. Essas populações ocorrem em comunidades constituídas por diferentes espécies e densidades populacionais que variam com a cultivar, estresse sobre a hospedeira e propriedades física, química e biológica do solo. O presente estudo teve como objetivos: descrever a estrutura da comunidade de nematóides associada ao cultivo comercial do mamoeiro em áreas com diferentes níveis populacionais de Meloidogyne sp. em Mamanguape, Paraíba, e determinar padrão de caminhamento e número de amostra, para monitoramento de populações de Meloidogyne sp. e Rotylenchulus sp. no campo. Foram avaliadas três áreas, com diferentes níveis populacionais de nematóide das galhas e reniforme. Em cada área, tomou-se 5.776 m2 que foi dividido em 400 (20 × 20) quadriláteros contíguos de 14,44 m2 (3,8 × 3,8 m),com três plantas por quadrilátero. Para descrição da estrutura da nematofauna, foram usados índices de comunidade de nematóides: índice de maturidade (MI), índice de parasitos de plantas (PPI) e índice de maturidade modificada (MMI), e razões entre grupos tróficos de nematóides. Para seleção do diagrama para coleta de amostras foram simulados padrões de caminhamento em “X”, diamante, linhas paralelas, barras paralelas, “V” invertido, zigue-zague, “W” invertido, “degrau”, “S”, aleatório e caminhamento geral. Para determinação do tamanho das amostras utilizou-se todos os padrões de caminhamento testados e variou-se o número de amostras (40, 30 e 20) dentro de cada padrão em cada área. As densidades populacionais (espécimes/300cm3 de solo) de ambas espécies, estimadas em função do número de amostras e padrão de caminhamento, foramcomparadas pelo teste de Kruskal-Wallis a 5% de probabilidade. Nas áreas 1 e 3 houve predominância de fitoparasitos, respectivamente 43,84 e 39,95 % do total de nematóides encontrados, destacando-se o gênero Rotylenchulus sp. Na área 2, Meloidogyne foi o taxon de maior dominância entre os fitoparasitos. Nas três áreas, MI e MMI foram altos (> 30%) e PPI variou de 20,95 a 32,88%. Vinte amostras por área foi indicado para monitoramento dos dois gêneros de nematóides, recomendando-se caminhamento aleatório, em diamante ou em barras paralelas para coleta de amostras de Meloidogyne sp. e caminhamento em linhas ou barras paralelas para Rotylenchulus sp.

Made available in DSpace on 2016-04-28T14:57:35Z (GMT). No. of bitstreams: 1 2008 - Rhadyson Reinaldo Silva do Nascimento.pdf: 1733739 bytes, checksum: b1070eca267f85de92499d2e245add23 (MD5) Previous issue date: 2008-09-03 / Cowpea (Vigna unguiculata L. Walp.) is a very important crop in Brazil, mainly in the north and northeast regions of the country, and is gaining importance in the southeast region. In this crop, nematodes are a great threat, because they can cause yield decrease. Information about these pathogens is very few. In a first approach this work aimed at surveying for the occurrence of plant parasitic nematodes that are associated to cowpea in the State of Rio de Janeiro, through sampling achieved in some locations of Nova Igua?u, Mag?, Serop?dica, S?o Francisco de Itabapoana, and Itagua?, where cowpea is grown cultivated. Eight genera of plant parasitic nematodes we found, besides others, that are free leving that were not identified. At the level of species M. incognita and Rotylenchulus reniformis were identified. Nematode identification was done on the bases of morphometric characteristics descriptive keys M. incognita by juvenile (J2 ) and males characteristics and perineal female patterns and esterases profile. In this step, surveys were carried out aiming at the detection of esterases activity for a population of R. reniformis. Protocols routinely used in isoezymes analysis were tested and showed negative results. On the other hand, assays using PCR tubes with the objective to identify esterase activity demonstrated that it was positive for R. reniformis. Modifications in the common protocols, such as changes in buffer solution at the and steps of the procedures, as well as adjusting pH near to neutrality enabled the establishment of a three band pattern of esterase in the studied populations of R. reniformis. In another phase of this work, six cowpea lines in advanced phase of improvement from determining their behavior when inoculated with M. incognita race 1, M. javanica and R. reniformis. The tomato cv. TRural was used as susceptible pattern. The experiments were carried out under greenhouse condition, using 5,000 eggs + juveniles per experimental plots, as inoculum level; for Meloidogyne species evaluation was done 50 days after nematodes inoculations based in the following parameters: galls indices (IG), egg mass indices (IMO) and reproductions rate (FR), calculated by the relation Pf/Pi ( Pf = final populations and Pi= start population). Among the tested lines, five of then RJ 04-04, RJ 04-08, RJ 04-26, RJ 04-48 and RJ 04-65 showed to be highly resistant and line RJ 04-29 was moderately resistant to M. incognita race 1. In the case of M. javanica all lines were highly susceptible. For evaluation of R. reniformis it was used as inoculum and "pure" population multiplied vegetation home. It was inoculated 5000 eggs and juvenile of males and of immature females. As parameter for evaluation of the resistance of the cowpea lineages to the nematode, the reproduction factor was used (Fr) appraised to the 45 days after inoculation. It was verified that all of the tested lineages were considered susceptible; to cultivate "Costel?o" included as witness showed equal behavior. / O caupi (Vigna unguiculata Walp.) ? uma cultura de grande import?ncia para o pa?s, principalmente na regi?o Norte e Nordeste e vem ganhando espa?o na regi?o Sudeste. Nesta cultura, os nemat?ides possuem influ?ncia significativa, chegando ao ponto de limitar a sua produ??o. As informa??es sobre estes pat?genos no Estado do Rio de Janeiro s?o escassas. Assim, numa primeira etapa, este trabalho teve por objetivo fazer um levantamento de nemat?ides fitoparasitas associados a cultura do caupi no Estado do Rio de Janeiro, por meio de coletas realizadas em alguns munic?pios produtores de caupi cultura. Foram encontrados, um total de oito g?neros de nemat?ides fitoparasitas, al?m de outros de vida livre n?o identificados. Em n?vel de esp?cie foram identificadas Meloidogyne incognita ra?a 2 e Rotylenchulus reniformis. As identifica??es foram efetuadas a partir de caracter?sticas morfom?tricas e aux?lio de chaves descritivas. M. incognita foi identificada pelas caracter?sticas dos juvenis (J2) e de machos, configura??o do modelo perineal das f?meas e perfil de esterases. Foram realizados ensaios com o objetivo de detec??o de atividade de esterase, para uma popula??o do nemat?ide R. reniformis. Para tanto foram testados protocolos rotineiramente usados em an?lises isoenzim?ticas, que apresentaram resultados negativos. Entretanto, ensaios montados em microtubos para PCR, evidenciaram atividade ester?sica para R. reniformis. Finalmente, modifica??es nos protocolos usuais como mudan?as na concentra??o da solu??o tamp?o de revela??o, assim como a fixa??o do pH da mesma pr?ximo a neutralidade, permitiram estabelecer um padr?o com tr?s bandas distintas de esterases na popula??o de R. reniformis estudada. Em uma segunda etapa deste trabalho, seis linhagens de caupi em fase avan?ada de melhoramento para resist?ncia a viroses, foram testadas visando determinar a rea??o das mesmas quando inoculadas com M. incognita ra?a 1, ou M. javanica, ou R. reniformis. A cultivar de tomate TRural foi usada como testemunha suscet?vel nos testes com as duas esp?cies de nemat?ide das galhas radiculares. Os experimentos foram realizados em casa de vegeta??o e usou-se uma carga de in?culo de 5000 ovos + juvenis/repeti??o; para as esp?cies de Meloidogyne a avalia??o ocorreu 50 dias ap?s inocula??o e os par?metros usados foram: ?ndice de galhas (IG), ?ndice de massa de ovos (IMO) e fator de reprodu??o (Fr) calculado pela rela??o Pf/Pi (Pf = popula??o final e Pi = popula??o inicial). Das cinco linhagens testadas, RJ 04-04, RJ 04-08, RJ 04-26, RJ 04-48 e RJ 04-65 comportaram-se como altamente resistentes e a linhagem RJ 04-29 como moderadamente resistente para M. incognita ra?a1. Enquanto que, para M. javanica, todas as linhagem foram altamente suscet?veis. Para avalia??o de R. reniformis foi usado como in?culo uma popula??o pura multiplicada em casa de vegeta??o. Inoculou-se 5000 ovos e/ ou juvenis de machos e de f?meas imaturas. Como par?metro para avalia??o da resist?ncia das linhagens de caupi ao nemat?ide, foi usado o fator de reprodu??o (Fr) avaliado aos 45 dias ap?s inocula??o. Verificou-se que todas as linhagens testadas foram consideradas suscet?veis; a cultivar Costel?o inclu?da como testemunha mostrou igual comportamento.