Biofertilizers in the control of Pratylenchus brachyurus in soybean crop

Nematodes are of great importance in soybean cultivation, especially the Pratylenchus brachyurus known as root lesion nematode. Its attack on plant roots causes less efficiency in the absorption of water and nutrients, in addition to damaging the plant's development. There is still no fully efficient method to control this phytopathogen, however, some products are available on the market, including biological control. Thus, the aim of this study was to evaluate commercial biological products in the efficiency of reducing the nematode population in soybean crop in Goiás, Brazil. The design was completely randomized in a 2x4 factorial scheme, the first factor being two soybean genotypes (Brasmax Bônus and Nidera NS 8383) and the second factor the treatments consisting of different dosages in an association of three commercial products: No-Estio®, Bio-fertility® and Radic®. The treatments used were: T1 control - without application of the products; T2 half the recommended dose; T3 the recommended dose and T4 a dose and a half that recommended by the manufacturer. Plant evaluation was carried out after 75 days of nematode inoculation. The results obtained showed that both cultivars hosted P. brachyurus, however, the treatments using the products had a lower population density of this nematode. It was concluded that the two soybean cultivars are hosts of Pratylenchus brachyurus. The agronomic character plant height was more affected when there was no application by the biological method. The association of No-Estio®, Bio-fertility® and Radic® products reduced the population density of nematodes in infected plants.

BIOLOGICAL NEMATICIDES ASSOCIATED WITH POULTRY LITTER IN THE CONTROL OF NEMATODES IN SOYBEAN AND SECOND CORN CROP

ABSTRACT Alternative management measures have been used to reduce nematode population levels in affected areas. In this perspective, the objective was to evaluate the efficiency of nematicides based on fungus and bacterium, associated with poultry litter applied via ground in the management of Pratylenchus brachyurus and Heterodera glycines in soybean and corn crops in succession. The experiment was conducted in the 2018/19 growing season in the municipality of Ipameri– GO (-17°34’55.58”S−48°12’02.35”O) in naturally infested field, arranged in a randomized block design, with 10 treatments and 4 replicates, being: T1- Witness/ control, T2- Poultry litter, T3- P. lilacinum + T. harzianum, T4- B. subtilis + B. licheniformis, T5- P. chlamydosporia, T6- Abamectina, T7- P. lilacinum + T. harzianum + Poultry litter, T8- B. subtilis + B. licheniformis + Poultry litter, T9- P. chlamydosporia + Poultry litter, T10- Abamectina + Poultry litter. The poultry litter was added in the soil 10 days before planting. The plots were composed of 6 lines of 6 m, with a spacing of 0.5 m. In the soybean crop at 45 and 90 days after sowing (DAS), the fresh weight of the roots (MFR), nematological variables and productivity were evaluated. In corn, only nematological variables were evaluated at 60 DAS. The treatments using P. lilacinum + T. harzianum and B. subtillis + B. licheniformes increased the MFR and reduced the number of P. brachyurus and H. glycines at the root. P. chlamydosporia associated with poultry litter increased in productivity in soybean plants.

Controle biológico no manejo de Pratylenchus brachyurus em diferentes tratamentos na cultura da soja

A cultura da soja possui grande importância para a economia brasileira e pode enfrentar entraves dos fatores bióticos e abióticos em sua produção, sendo os nematoides expoentes na redução da produtividade desta cultura. Desse modo, este trabalho teve como objetivo avaliar o efeito de produtos biológicos para o controle de Pratylenchus brachyurus na cultura da soja. O experimento foi realizado na casa de vegetação e no Laboratório de Fitopatologia e Nematologia do Centro Universitário Católica do Tocantins. O delineamento experimental foi inteiramente casualizado consistindo em cinco tratamentos com diferentes produtos biológicos: T1 – testemunha (sem tratamento), T2 - Presence® (Bacillus subtilis e Bacillus licheniformis), T3 - Votivo Prime® (Bacillus firmus), T4 - Ecotrich® (Trichoderma harzianum) e T5 – Nemat® (Paecilomyces lilacinus) com quatro repetições. Para avaliação da eficiência do controle biológico de nematoides, procedeu-se o tratamento prévio das sementes de soja no momento da semeadura. O tratamento das sementes foi realizado individualmente, adicionando os produtos conforme dosagem estabelecida na recomendação da bula. Aos 30 dias após a inoculação, foram avaliadas a características, comprimento da raiz, tamanho de planta, número de nematoides e severidade. Os produtos utilizados não interferiram no comprimento da raiz e no número de nematoides. O produto T3 – Votivo Prime®, apresentou melhor resultado quando se avalia o comprimento de planta. A severidade foi menor quando se faz uso de algum tipo de produto para controle biológico.

Molecular Diagnosis and Evolutionary Relationship Analysis Of Plant Parasitic Tea Garden Nematodes From Different Tea Estates In Sylhet Region of Bangladesh

Nematodes from plant-parasitic sources are ever-present and incidental to plant growth as well as crop production. The damage of tea gardens caused by nematode is often non-specific and easily confused with symptoms. The present study determined the parasitic and non-parasitic nematodes population in different tea gardens of the Sylhet region by their morphological and partial molecular characterization. Out of 13 tea gardens, it was observed that BTRI, Karimpur, Mathiura, and Tarapur tea garden has the highest number of parasitic and non-parasitic nematodes. After PCR amplification, DNA bands with desired amplicon size were detected by gel electrophoresis. Among thirteen soil samples, nematodes from Malnichara, Karimpur, BTRI, Mathiura , and Finlay had partially confirmed the presence of rootknot nematode (Meloidogyne spp.), root-lesion nematode (Pratylenchus brachyurus), burrowing nematode (Radopholus similis), reniform nematode (Rotylenchulus reniformis) and lance nematode (Hoplolaimus columbus) consequently based on approximately base pair of 1.7, 1.1 and 0.52 kb (different Meloidogyne spp.) 0.52, 0.52, 0.25 and 2.3 kb of specific genes. From evolutionary analysis, it might be said that Meloidogyne species are strongly related with each other making clusters except Meloidogyne natalie where this one is closely related with Hoplolaimus columbus in their evolutionary relationship as remaining others (Rotylenchulus reniformis, Radopholus similis, Pratylenchus brachyurus) are in different clusters in the same clade and this result could be confirmed after sequencing. J. Bio-Sci. 29(1): 101-109, 2021 (June)

Population Dynamics of Pratylenchus brachyurus in Maize Treated with Inorganic Fertilizer

Field studies were conducted in the early and late season of 2010 in the tropical rainforest zone of Nigeria to investigate the effects of NPK fertilizer as an inorganic soil amendment at 75 kg/ha and 150 kg/ha in four replications on population densities of Pratylenchus brachyurus and on crop yield of maize. Seeds of maize variety, DMR LSR-Y were collected from Institute of Agricultural Research and Training, Ibadan. The experimental field was naturally infested with Pratylenchus spp. due to subsequent continuous cultivation of susceptible crop on the field. Seeds were planted and NPK was applied around the roots of maize plants 3 weeks after seedling emergence. Soil samples were taken on treatment plots at planting and harvest to determine the percentage change in nematode population. At the end of experiment, NPK application resulted in the increase in the nematode population. However, the grain yield of maize was not reduced by the increased nematode densities. The results of this study suggests that the usage of NPK caused a surge in the nematode reproduction on the field due to the availability of more feeding sites on the actively growing root system of the crop.

IMPACT OF CHEMICAL COMPOUNDS INTERACTIONS ON SEED TREATMENTS TO CONTROL THE SOYBEAN NEMATODE 𝘗𝘳𝘢𝘵𝘺𝘭𝘦𝘯𝘤𝘩𝘶𝘴 𝘣𝘳𝘢𝘤𝘩𝘺𝘶𝘳𝘶𝘴

Pratylenchus brachyurus se destaca entre as espécies de fitonematoides que mais causam prejuízos na cultura da soja no Brasil. O trabalho teve como objetivo avaliar as interações de diferentes grupos químicos no tratamento de sementes para o controle de P.brachyurus. Os experimentos foram conduzidos em casa de vegetação sendo o delineamento inteiramente casualizado, composto por nove tratamentos e seis repetições, sendo Produto A = tiofanato metílico; Produto B = piraclostrobina; Produto C = fipronil; Produto formulado A+B+C = piraclostrobina + tiofanato metílico + fipronil e Padrão controle = abamectina. As interações químicas foram: Produto A+B = tiofanato metílico + piraclostrobina; Produto A+C = tiofanato metílico + fipronil; Produto B+C = piraclostrobina + fipronil. Tratamentos com sementes sem aplicação de produtos foram mantidos como controle. Todos os produtos combinados apresentaram efeito antagônico, porem o composto fipronil isolado ou combinado com o composto tiofanato metílico se destacou no controle de P. brachyurus.

Suppression of Pratylenchus brachyurus and soybean growth inoculated with arbuscular mycorrhizal fungus

Arbuscular mycorrhizal fungi perform a variety of plant-beneficial processes. including increased resistance to disease. The objective of this work was to study arbuscular mycorrhizal fungus Rhizoglomus clarum effect on phytonematode Pratylenchus brachyurus suppression and on soybean plants growth. Two experiments were performed under greenhouse conditions. First. soybean plants growth was evaluated in mycorrhizal fungi presence and absence. In the second experiment. phytonematode damage in soybean cultivated in mycorrhizal fungi presence and absence was evaluated. During soybean flowering was evaluated mycorrhizal colonization, dry matter, nodulation, chlorophyll and nutrient content in plant tissue, nematodes number in soil and root penetration, and nematode reproduction factor was obtained, R. clarum mycorrhizal colonization reduced by 64% the number of nematodes penetrated in roots and increased soybean plants nodulation, nutrient absorption and dry matter accumulation. The stimulation to mycorrhization is a strategy to reduce damage caused by Pratylenchus brachyurus to soybean plants.

Pratylenchus in sugarcane: a diminishing problem?

This chapter focuses on the economic importance, host range, geographical distribution, damage symptoms and biology and life cycle of Pratylenchus brachyurus, P. neglectus, P. scribneri and P. zeae infesting sugarcane in South Africa. Information on their interactions with other nematodes and pathogens, the efficacy and optimization of some recommended integrated nematode management programmes and future nematode research requirements are also presented.

Uso de esterco bovino e cobertura de solo no manejo de nematoides na cultura da soja

As doenças causadas por nematoides são consideradas importantes devido ao hábito polífago desses patógenos, estratégias de sobrevivência e aos prejuízos econômicos causados. No Brasil, as espécies que provocam os maiores danos na cultura da soja são: Meloidogyne javanica, M. incognita, Heterodera glycines, Pratylenchus brachyurus, Rotylenchulus reniformis e Aphelenchoides sp. Recentemente, surgiram relatos de incidência, em algumas regiões, de Tubixaba spp., Scutellonema brachyurus e Helicotylenchus dihystera. Dessa forma, é necessária a utilização de estratégias de manejo que auxiliem na redução dos níveis populacionais desses fitoparasitas. O uso de esterco bovino, associado a espécies vegetais para cobertura de solo, apresentase como uma alternativa para manejo de nematoides na cultura da soja, devido a um conjunto de propriedades nematostáticas e nematicidas, ao efeito benéfico às plantas e ao estímulo do desenvolvimento de inimigos naturais. São indicadas espécies de plantas que produzam resíduos que cubram melhor o solo, deixem mais palhada, distribuam seus sistemas radiculares pivotantes e/ou fasciculados, mantenham ou aumentem os teores de carbono, e incrementem a densidade/ riqueza macro e microbiológica. Esta revisão tem o objetivo de apresentar e discutir os principais efeitos do uso de matéria orgânica e alternativas de manejo e controle de nematoides na cultura da soja com o emprego de esterco bovino e cobertura de solo com diferentes espécies de plantas.