Efficacy of Purpureocillium lilacinum AUMC 10149 as biocontrol agent against root-knot nematode Meloidogyne incognita infecting tomato plant / Eficácia de Purpureocillium lilacinum AUMC 10149 como agente de biocontrole contra o nematoide Meloidogyne incógnita que infecta plantas de tomate

Abstract Root-knot nematode Meloidogyne incognita is among the biotic factors which has greatly affected both the yield and the quality of the tomato crop. The egg parasitic nematode, Purpureocillium lilacinum (Pl) is considered as one of the most promising agents in controlling and overcoming this plant pathogen. The nematicidal effect of the native isolate Pl AUMC 10149 on second stage juvenile's survival and egg hatching of M. incognita at different times of exposure was tested in vitro. The obtained data showed that Pl gave a maximum percentage of J2 mortality (97.6%) and egg hatching inhibition (79.8%) after 72 hours of exposure. The potentiality of Pl as well as Bio-Nematon to control M. incognita infecting tomato was conducted using different times of application in vivo. Nine treatments with five replicates were used for such bioagents compared with the nematicide Oxamyl. Each seedling was inoculated with 1000 J2s of nematode/pot and 10 mL of Pl (1x1010 CFU/mL) or Bio-Nematon spore suspension (1x108 CFU/mL) 10mL/pot. The results indicated that the most effective treatments in reducing nematode population, number of galls and egg masses of M. incognita in plant roots was performed with treatment by Pl pre-planting and post-infection with Pl (Rf 1.9) giving a significant enhancement in plant length (64.9%), fresh weight (72.52%) and shoot dry weight (163.41%) without negatively impacting environment. Therefore, the present study confirmed that using P. lilacinum AUMC 10149 can be used as a practical supplement to environmentally friendly disease management of root-knot nematodes in Egypt.

Resumo O nematoide-das-galhas Meloidogyne incognita está entre os fatores bióticos que afetaram enormemente a produção e a qualidade da cultura do tomate. O nematoide parasita de ovos, Purpureocillium lilacinum (Pl), é considerado um dos mais promissores agentes no controle e superação desse fitopatógeno. O efeito nematicida do isolado nativo Pl AUMC 10149 na sobrevivência de juvenis de segundo estágio e na eclosão dos ovos de M. incognita em diferentes momentos de exposição foi testado in vitro. Os dados obtidos mostraram que o Pl deu um percentual máximo de mortalidade de J2 (97.6%) e inibição da eclosão dos ovos (79.8%) após 72 horas de exposição. A potencialidade de Pl e de Bio-Nematon para controlar M. incognita infectando tomate foi conduzida em diferentes tempos de aplicação in vivo. Nove tratamentos com cinco repetições foram usados ​​para tais bioagentes em comparação com o nematicida Oxamyl. Cada muda foi inoculada com 1.000 J2s de nematoide / vaso e 10 mL de Pl (1×1010 CFU/mL). Ou suspensão de esporos Bio-Nematon (1×108 CFU/mL) 10mL/pot. Os resultados indicaram que os tratamentos mais eficazes na redução da população de nematoides, número de galhas e desovas de M. incognita nas raízes das plantas foram realizados com Pl pré-plantio e pós-infecção com Pl (Rf 1.9), dando um aumento significativo no comprimento da planta (64.9%), massa fresca (72.52%) e massa seca da parte aérea (163.41%) sem impactar negativamente o meio ambiente. Portanto, o presente estudo confirmou que o uso de P. lilacinum AUMC 10149 pode ser usado como um suplemento prático para o manejo ecologicamente correto de nematoides-das-galhas no Egito.

Suppression and management of Meloidogyne incognita in soil using Trichoderma harzianum NFCF160 and Trichoderma virens Isf-77

Aims@#Meloidogyne incognita adversely affects numerous crop plants worldwide. Therefore, the modern world has been moving towards biocontrol methods to prevent nematode attacks. This study was aimed to (i) investigate the potential use of Trichoderma harzianum NFCF160 and T. virens Isf-77 in managing M. incognita in soil and (ii) identify trapping mechanisms employed by both Trichoderma strains to suppress M. incognita.@*Methodology and results@#Three weeks old, Basella alba L. plants were subjected to five different treatments. The above and below ground growth parameters and the galling indices of these plants were measured every four weeks for three sampling times. Trapping mechanisms employed by Trichoderma strains were examined following plate assays. Plants treated with T. harzianum NFCF160 and T. virens Isf-77 had significantly higher values for the total number of leaves (34 ± 2.84) and (27 ± 2.61), fresh weight of the shoot (81 ± 9.51 g) and (91 ± 9.70 g), dry weight of the shoot (71 ± 5.24 g) and (62 ± 5.81 g), respectively eight weeks after inoculation of M. incognita. Significantly low galling indices (2 and 2) were recorded in B. alba treated with Trichoderma strains. Both Trichoderma strains exhibited various nematode-trapping mechanisms, such as non-constricting rings and adhesive spores.@*Conclusion, significance and impact of study@#This investigation highlighted the potential of both Trichoderma strains as biocontrol agents to control M. incognita effect in sustainable agriculture.

Survey of nematodes associated with sugarcane in the state of Paraná, Brazil

Sugarcane-associated nematodes (Saccharum spp.) can reduce productivity up to 50%. Through the survey, it was possible to identify the main nematodes that occur in a certain region as a tool for designing the best management and control strategies. The aim of this study was to characterize the population of nematodes associated with sugarcane in the North Central, North Pioneiro and Northwest mesoregion of the state of Paraná, Brazil, quantify the nematode genera associated with the crop and identify the species of Pratylenchus and Meloidogyne. A total amount of 89 soil and root composite samples were collected in nine municipalities. Nematodes were extracted and counted in a Peters counting chamber under an optical light microscope. Morphological description followed identification keys. Pratylenchus spp. were identified by morphological characteristics; Meloidogyne spp. were identified by morphological characteristics and isoenzyme electrophoresis. Twelve genera of nematodes associated with sugarcane were identified: Pratylenchus, Meloidogyne, Helicotylenchus, Xiphinema, Mesocriconema, Trichodorus, Aphelenchus, Hoplolaimus, Tylenchus, Tylenchorhynchus, Ditylenchus, and Paratrichodorus. The genera Pratylenchus and Meloidogyne were found with the highest frequencies in the roots. Among the species of Pratylenchus, P. zeae and P. brachyurus were found, with P. zeae being the most frequent. Among the Meloidogyne species, only M. javanica was found. These results are essential to aid decision making in the management of phytonematodes, mainly in the development of new control strategies and in directing genetic breeding programs for development of sugarcane cultivars for the Paraná state.

Biological control of Meloidogyne javanica in bean plants by Hohenbuehelia spp. and Trichoderma koningiopsis

Nematode control strategies are limited and alternative control is demanded. The main aim was to evaluate control potential of Hohenbuehelia spp. (Hohenbuehelia mastrucata, Hohenbuehelia barbatula, Hohenbuehelia bullulifera, Hohenbuehelia portegna, Hohenbuehelia petaloides and Hohenbuehelia paraguayensis) and Trichoderma koningiopsis against Meloidogyne javanica in bean plants in greenhouse. The parameters evaluated were the number of galls and egg masses which were evaluated in three root regions: basal, intermediate and tip; nematode reproduction factor; vegetal growth parameters (plants height on V1, V2, V4, and R5 growth stages, root length, dry weight of root and aerial part dry weight); Treatments were composed by individual interactions of each fungal isolate with 4,000 eggs of M. javanica, having a total control (bean) and a partial control (bean + nematode) arranged in completely randomized design with four repetitions. Data were tested by Scott­Knott (5%). For vegetal growth parameters, there was only significance for dry weight of roots. All species were able to control nematodes.

Host status of eucalypt species to Pratylenchus brachyurus and Meloidogyne incognita

Plant parasitic nematodes are major threats to Brazilian and world agriculture. Among them, Pratylenchus brachyurus and Meloidogyne incognita stand out as major pests for several crops, including corn, cotton, soybean among others, which can be components of integrated crop-livestock-forestry systems (ICLFs). In this context, information about the host status of eucalypts (Corymbia spp. and Eucalyptus spp.) to plant parasitic nematodes becomes more relevant in Brazil, due to the use of eucalypts in ICLFs. If tree components used on this system increase the population density of P. brachyurus and M. incognita, it is possible that these pathogens could damage shorter-cycle crops. Since information about the host status of eucalypts to plant parasitic nematodes is scarce, this study evaluated the host status of some eucalypt species to P. brachyurus and M. incognita. Two greenhouse trials were done to evaluate the reproduction of P. brachyurus and one to M. incognita, using some of the most cultivated species and hybrids of eucalypts in Brazil. The population growth of P. brachyurus increased on Corymbia citriodora, Eucalyptus grandis, Eucalyptus dunnii × Eucalyptus urophylla, and E. grandis × E. urophylla after ~90 days of inoculation. Conversely, despite M. incognita reproducing well in the control plants, no individuals were recovered from C. citriodora, E. urophylla and E. grandis × E. urophylla, which were classified as resistant plants. Based on both obtained and available data, M. incognita poses no threat to eucalypt species today. However, P. brachyurus is suggested to be a threat to eucalypts.

Phytonematodes infesting common bean fields in Brazil, and pathogenicity tests with Pratylenchus brachyurus

Phytonematodes are among the main pathogens of the common bean. In general, control practices that aim to control these pathogens have not been regularly adopted in Brazil. The objectives of the present study were to evaluate the occurrence of phytonematodes in dry bean fields in Paraná and São Paulo states and estimate the pathogenicity of Pratylenchus brachyurus to dry bean in glasshouse experiments. Root and soil were sampled for nematode extraction, identification and estimation of population density. Four glasshouse experiments with different initial population densities were carried out to evaluate the effect of P. brachyurus on the growth of dry bean plants. Six species of phytonematodes were detected, namely Helicotylenchus dihystera, P. brachyurus, Pratylenchus crenatus, Meloidogyne javanica, Meloidogyne incognita and Rotylenchulus sp. The spiral nematode H. dihystera was found in all samples and was the most abundant species in both states. The lesion nematode P. brachyurus was also frequent, reaching 94% in Paraná and 100% in São Paulo. The root-knot nematodes and Rotylenchulus sp. were reported only in São Paulo fields (45% and 18% frequency, respectively), and P. crenatus only in Paraná (12%). The most abundant nematode in the soil was H. dihystera, and in roots was P. crenatus. It was demonstrated that densities of 6.66 specimens of P. brachyurus per cm3 of soil provoke visible and measurable root decay. In conclusion, survey data showed low phytonematode densities and pathogenicity tests demonstrated that densities above 6.67 specimens of P. brachyurus per cm3 of soil cause damage to the dry bean roots.

Phytochemical management of root knot nematode (Meloidogyne incognita) kofoid and white chitwood by Artemisia spp. in tomato (Lycopersicon esculentum L.) / Manejo fitoquímico do nematoide do nódulo de raiz (Meloidogyne incognita) kofoid e do chitwood branco por Artemisia spp. em tomate (Lycopersicon esculentum L.)

Abstract In vitro and screen house experiments were conducted to investigate the effectiveness of thirteen phytochemicals from Artemisia elegantissimia and A. incisa on root knot nematode, Meloidogyne incognita in tomato (Lycopersicon esculentum L.) cv. Rio Grande. A positive control (Carbofuran) and negative control (H2O) were also used for comparison. Effectiveness of phytochemicals against juveniles (J2s) mortality and egg hatch inhibition were evaluated after 24, 48 and 72 hours of incubation at three concentrations viz; 0.1, 0.2 and 0.3 mg/mL in vitro conditions. Amongst thirteen phytochemicals, Isoscopletin (Coumarin), Carbofuran and Apigenin (Flavonoid) showed the highest mortality and egg hatch inhibition of M. incognita at all intervals. Inhibition of eggs and J2s mortality were the greatest (90.0%) and (96.0%) at 0.3 mg/mL concentration. Application of phytochemicals caused reduction in number of galls, galling index, and egg masses on tomato plant and enhanced plant growth parameters under screen house conditions. Gall numbers (1.50), galling index (1.00), number of juveniles (4.83) and egg masses (4.00) were greatly reduced and plant growth parameters such as; plant height (28.48 cm), fresh (72.13 g) and dry shoot weights (35.99 g), and root fresh (6.58 g) and dry weights (1.43 g) were increased significantly by using Isoscopletin. In structure activity relationship, juveniles of M. incognita, exhibited variations in their shape and postures upon death when exposed to different concentrations of phytochemicals of Artemisia spp. The present study suggests that Artemisia based phytochemicals possess strong nematicidal effects and can be used effectively in an integrated disease management program against root knot nematodes.

Resumo Experimentos in vitro e de triagem foram conduzidos para investigar a eficácia de treze constituintes fitoquímicos de Artemisia elegantissimia e A. incisa no nematóide de galhas, Meloidogyne incognita em tomateiro (Lycopersicon esculentum L.) cv. Rio Grande. Um controle positivo (carbofuran) e controle negativo (H2O) também foram utilizados para comparação. A eficácia dos fitoquímicos contra a mortalidade juvenil (J2s) e a inibição da eclosão de ovos foram avaliadas após 24, 48 e 72 horas de incubação em três concentrações, tais como: 0,1; 0,2 e 0,3 mg/mL em condições in vitro. Dentre os treze fitoquímicos, isoscopletina (cumarina), carbofurano e apigenina (flavonoide) apresentaram a maior mortalidade e a inibição da eclosão de ovos de M. incognita em todos os intervalos. A inibição da mortalidade dos ovos e J2s foi a maior (90,0%) e (96,0%) na concentração de 0,3 mg/mL. A aplicação de fitoquímicos causou redução no número de galhas, índice de fricção e massa de ovos no tomateiro e melhorou os parâmetros de crescimento das plantas em condições de triagem. Números de galhas (1,50), índice de insetos galhadores (1,00), número de juvenis (4,83) e massas de ovos (4,00) foram bastante reduzidos e os parâmetros de crescimento das plantas, como altura da planta (28,48 cm), peso fresco (72,13 g) e seco (35,99 g), raiz fresca (6,58 g) e peso seco (1,43 g) foram significativamente aumentados usando isoscopletina. Na relação atividade estrutura, juvenis de M. incognita, exibiram variações em sua forma e posturas após a morte quando expostos a diferentes concentrações de fitoquímicos de Artemisia spp. O presente estudo sugere que os fitoquímicos à base de artemísia possuem fortes efeitos nematicidas e podem ser usados ​​eficazmente em um programa integrado de controle de doenças contra nematóides de galhas.

Immunity of sugarcane cultivars to Meloidogyne enterolobii / Imunidade de cultivares de cana-de-açúcar a Meloidogyne enterolobii

Brazil is currently the world's largest producer and exporter of sugarcane, and the crop has high socioeconomic importance in the country. Root-knot nematodes (Meloidogyne spp.) are one of the major limiting factors in sugarcane production. These plant parasites have wide geographic distribution, high damage potential, and are difficult to control. Recently, the species Meloidogyne enterolobii was identified in sugarcane crops in the state of Pernambuco, Brazil. Given the importance of genetic resistance for integrated nematode management and the lack of research on the M. enterolobii­sugarcane pathosystem, this study aimed to assess the response of sugarcane cultivars to M. enterolobii. Thirteen cultivars were evaluated for their resistance to M. enterolobii based on the nematode reproduction factor. The experiment was conducted in a greenhouse, in a completely randomized design, with 14 replicates. Pre-sprouted sugarcane seedlings were transplanted to 5 L pots, and each pot was considered an experimental unit. At 15 days after transplanting, the seedlings were inoculated with 5,000 eggs and second-stage juveniles of M. enterolobii. Tomato and okra plants were also inoculated to test the viability of the inoculum. At 240 days after inoculation, plant roots were processed and evaluated for nematode number. This parameter was used to calculate the nematode reproduction factor on each cultivar. All sugarcane cultivars were found to be immune to M. enterolobii, with a reproduction factor of 0.

O Brasil é atualmente o maior produtor e exportador mundial de cana-de-açúcar, tendo a cultura grande impacto socioeconômico no país. Dentre os diversos fatores que podem afetar sua produção se destacam os nematoides de galha (Meloidogyne spp.), por apresentarem ampla distribuição geográfica, alto potencial danoso e difícil controle. Recentemente a espécie Meloidogyne enterolobii foi identificada parasitando a cultura da cana-de-açúcar em Pernambuco. Dada à importância da resistência genética no manejo integrado de fitonematoides e a falta de trabalhos envolvendo o estudo desta espécie na cultura, o presente trabalho teve como objetivo avaliar a resposta de cultivares de cana-de-açúcar a M. enterolobii. Foram avaliadas 13 cultivares quanto a sua resistência a esta espécie com base no fator de reprodução do nematoide. O experimento foi conduzido em delineamento inteiramente casualizado, com 14 repetições, e mantido em casa de vegetação. Foram utilizadas mudas pré-brotadas de cana-de-açúcar, transplantadas para vasos de 5L, sendo cada vaso considerado uma unidade experimental. Cada unidade experimental foi inoculada com 5.000 ovos e juvenis de segundo estádio de M. enterolobii 15 dias após os transplantio. Plantas de tomateiro e quiabeiro também foram inoculadas para atestar a viabilidade do inoculo utilizado no experimento. Decorridos 240 dias da inoculação as raízes foram processadas para obtenção da população final e cálculo do fator de reprodução do nematoide de cada tratamento. Todas as cultivares de cana-de-açúcar avaliadas foram resistentes/imunes à M, enterolobii, apresentando fator de reprodução igual a zero.

Physiological changes in Solanum lycopersicum L. in the presence of root-knot nematodes and salicylic acid / Alterações fisiológicas em Solanum lycopersicum L. na presença de nematóides das galhas e ácido salicílico

Nematodes of the genus Meloidogyne spp. are one of the tomato culture's main pathogens. According to their soil infestation level, physiological changes may occur. Consequently, it is extremely important to employ given products to minimize their effect. A feasible option is the salicylic acid, a phytohormone that can induce into resistance due to its ability to increase the production level of some pathogenicity proteins. Therefore, the purpose hereof was to assess the effect of salicylic acid on the physiology of tomato plants subject to different populational densities of Meloidogyne javanica. The design employed was one of randomized blocks, in an incomplete factorial scheme, using the Box Central Compound (BCC) matrix with five nematode populational densities (PD) (0; 5815; 20000; 34184; and 40000 eggs per plant) and five salicylic acid doses (0.0; 0.29; 1.0; 1.71; and 2.0 mM), with four repetitions and two plants per experimental patch. The gas exchanges, fluorescence, and chlorophyll levels were evaluated 45 days after the transplant and soil infestation. The data were submitted for analysis of variance through the F test and, in the significance cases, the polynomial regression analysis was performed. For stomatal conductance, a greater reduction was seen at the PD of 21755 eggs per plant, a fact that might have decreased the liquid assimilation of CO2 and the efficiency of carboxylation. The salicylic acid (SA) affected the CO2 liquid assimilation and the efficiency of carboxylation. The infestation of M. javanica in tomato plants negatively affected the gas exchange and the chlorophyll levels because the SA application did not mitigate the negative effect thereof.

Os nematoides do gênero Meloidogyne spp. são um dos principais patógenos na cultura do tomate, podendo causar alterações fisiológicas em função do nível de infestação do solo. O uso de produtos que minimize seus efeitos é de suma importância, nesse sentido, o ácido salicílico pode ser uma alternativa viável, visto que, esse fitormônio pode induzir a resistência devido à capacidade de proporcionar um aumento na produção de algumas proteínas de patogenicidade. Com isso, objetivou-se avaliar o efeito do ácido salicílico na fisiologia do tomateiro submetido a diferentes densidades populacionais de Meloidogyne javanica. O delineamento utilizado foi o de blocos casualizados, em esquema fatorial incompleto, utilizando-se a matriz Composto Central de Box (CCB) com cinco densidades populacionais (DP) de nematoides (0; 5815; 20000; 34184 e 40000 ovos por planta) e cinco doses de ácido salicílico (0,0; 0,29; 1,0; 1,71 e 2,0 mM), com quatro repetições e duas plantas por parcela experimental. Foram avaliadas as trocas gasosas, fluorescências e índices de clorofilas aos 45 dias após o transplantio e infestação do solo. Os dados foram submetidos à análise de variância pelo teste F e nos casos de significância foi realizada análise de regressão polinomial. Para a condutância estomática, observou-se uma maior redução na DP de 21755 ovos por planta, fato que pode ter ocasionado reduções na assimilação líquida de CO2 e na eficiência de carboxilação. O ácido salicílico (AS) influenciou na assimilação líquida de CO2 e eficiência de carboxilação. A infestação por M. javanica em plantas de tomateiro influenciou negativamente nas trocas gasosas e nos teores de clorofila, sendo que a aplicação do AS não atenuou os efeitos negativos desses patógenos.

Root-knot nematode, Meloidogyne javanica, in response to soil fertilization / Nematoide-das-galhas, Meloidogyne javanica, em resposta à fertilização do solo

Abstract Root-knot nematodes (RKNs) (Meloidogyne spp.) are well known disease problem causing major losses in vegetable crops. Although, chemical nematicides have been used as one of the primary means for controlling RKNs, reliance on these nematicides is associated with heavy costs and negative effects on human health and environment. In this research, the suppressing potential of 6 Iranian commercial fertilizers on RKNs was investigated in laboratory and greenhouse conditions as an alternative to reduce the use of chemical nematicides. For this purpose, M. javanica inoculum was thoroughly mixed with autoclaved sandy loam soil. Then, 6 fertilizers (biofertilizer, phosphate chemical fertilizer (phosphate), potassium chemical fertilizer (potassium), peat moss, vermicompost, and leaf mold) were added individually to the inoculated soil, according to the defined treatments. The nematicide Cadusafos was used as a positive control. A negative control was also included in the experiment (including no fertilizer and no nematicide). Four-leaf seedlings of the tomato (Super Chief cv.) were transferred to the pots filled using 2 kg of the treated soil. After 60 days, reproduction factor (RF), egg mass, and root galling of the nematode were recorded. The results showed that, fertilizer-treated soils had significantly (P≤0.05) lower root galling, egg mass, and RF compared to the negative control. After the nematicide treatment, the highest suppression capability on the RKN was obtained in treatments of phosphate, biofertilizer, potassium, vermicompost, peat moss, and leaf mold, respectively. It can be concluded that, replacing chemical nematicides with fertilizers may be considered as a successful nematode management in tomato fields.

Resumo Nematoides-das-galhas das raízes (RKNs) Meloidogyne spp. causam perdas consideráveis na produção de hortaliças em todo o mundo. Embora o uso de nematicidas químicos seja um dos principais meios de controle de RKNs, a dependência nesses nematicidas está associada aos altos custos e impactos negativos à saúde humana e ao meio ambiente. No presente estudo, foi investigado o potencial de supressão de seis fertilizantes comerciais iranianos em RKNs em condições de laboratório e estufa, a fim de reduzir o uso de nematicidas químicos. Para este propósito, o inóculo de M. javanica foi totalmente misturado com o solo franco-arenoso autoclavado. Em seguida, os fertilizantes (biofertilizante, fertilizante químico de fosfato (fosfato), fertilizante químico de potássico (potássio), musgo de turfa, vermicompostagem e bolor) foram adicionados e misturados individualmente ao solo inoculado, de acordo com os tratamentos definidos. O nematicida Cadusafós foi utilizado como controle positivo. Um controle negativo também foi considerado (sem fertilizante e sem nematicida). Mudas de quatro folhas do tomate (Super Chief cv.) foram transferidas para vasos cheios de 2 kg de solo tratado. Após 60 dias, o fator de reprodução (FR), a massa de ovos e o número de galhas foram registrados. Os resultados mostraram que os tratamentos com fertilizantes apresentaram significativamente (P≤0,05) menor número de galhas nas raízes, massa de ovos e FR, em comparação com o controle negativo. Depois do controle positivo, a maior capacidade de supressão de M. javanica foi obtida nos tratamentos com fosfato, biofertilizante, potássio, vermicompostagem, turfa e bolor, respectivamente. Conclui-se que a substituição de nematicidas químicos por fertilizantes pode ser uma estratégia aceitável para se alcançar uma gestão bem-sucedida de nematoides em campos de tomate.

Crotalaria and millet as alternative controls of root-knot nematodes infecting okra / Crotalária e milheto como controles alternativos de nematóides das galhas infectando quiabo

The relationship of crops grown in rotation or in succession has increased every day and the use of antagonistic plants and/or non-host plants is one of the most efficient practices of integrated management of nematodes. This study aimed to evaluate the efficiency of crotalaria (Crotalaria spectabilisRoth) and millet [Pennisetum glaucum (L.) Leeke] 'ADR 300' in reducing the population of Meloidogyne incognita and M. javanica and in increasing the productivity of okra [Abelmoschus esculentus (L.) Moench] when cultivated in succession. The experiment was conducted in an area cultivating okra (host culture) in rotation, with a history of severe infestation by phytonematodes. The experimental design involved randomized blocks with six treatments and four replicates, with the following treatments: T1, 15 kg.ha-1 of millet seeds; T2, 30 kg.ha-1 of crotalaria; T3, 10 kg.ha-1 of millet + 20 kg.ha-1 of crotalaria; T4, 20 kg.ha-1 of millet + 6 kg.ha-1 of crotalaria; T5, 6 kg.ha-1 of millet + 36 kg.ha-1 of crotalaria; and T6, control. The nematode populations in the soil and roots were evaluated about 60 d after planting okra, and the yield was evaluated at the end of the crop cycle. Simple treatment with millet or crotalaria reduced the nematode population by 61% and 72%, respectively. The millet-crotalaria intercropping treatments reduced the nematode population by up to 85% compared with the control. In terms of productivity, there was an increase of 787 kg.ha-1 in the millet treatment and 2,109 kg.ha-1 in the intercropping treatments. Both the single cultivation of crotalaria or millet and the consortia of crotalaria and millet were effective in controlling the root-knot nematodes, and increased the productivity of okra.

A relação de culturas cultivadas em rotação ou em sucessão tem aumentado a cada dia, e a utilização de plantas antagônicas e/ou plantas não hospedeiras é uma das práticas mais eficientes de manejo integrado de nematoides. O trabalho teve como objetivo avaliar a eficiência do cultivo de crotalária (Crotalaria spectabilis Roth) e milheto [Pennisetum glaucum (L.) Leeke] 'ADR 300' no incremento de produtividade e redução populacional de Meloidogyne incognita e M. javanica em quiabeiro [Abelmoschus esculentus (L.) Moench] cultivado em sucessão. O experimento foi conduzido em área de rotação com quiabeiro (cultura hospedeira), que tem histórico de grande infestação dos referidos fitonematoides. O delineamento experimental adotado foi o de blocos casualizados com seis tratamentos e quatro repetições, sendo T1 ₌ 15 kg.ha-1 de sementes de milheto, T2 ₌ 30 kg.ha-1 de crotalária, T3 ₌ 10 kg.ha-1 de milheto + 20 kg.ha-1 de crotalária, T4 ₌ 20 kg.ha-1 de milheto + 6 kg.ha-1 de crotalária, T5 ₌ 6 kg.ha-1 de milheto + 36 kg.ha-1 de crotalária e T6 ₌ Testemunha. Foram avaliadas as populações de nematoides no solo e nas raízes cerca de 60 dias após o plantio do quiabeiro e a produtividade ao final do cultivo. Os tratamentos milheto e crotalária solteiros reduziram a população de nematoides em 61 e 72%, respectivamente. Nos cultivos consorciados, obteve-se a redução de 85%, comparado com a testemunha. Quanto a produtividade, houve acréscimo de 787 kg.ha-1 no tratamento com milheto solteiro e de 2.109 kg.ha-1 nos tratamentos consorciados. Tanto o cultivo solteiro de crotalária e milheto, quanto seu uso em consórcio, efetivaram o controle dos nematoides de ganha e elevaram a produtividade do quiabeiro.

Development of quantitative detection method for Meloidogyne incognita by qPCR / Desenvolvimento do método de detecção quantitativo para Meloidogyne incognita por qPCR

The root-knot nematode (Meloidogyne spp.) is the most important plant-parasitic nematode genus, they are the most common and destructive pathogens in this group. They produce some of the most drastic symptoms in plants and can significantly reduce the yield of crops. In order to achieve deploy an efficient method of plant-parasitic nematode management, is necessary an identification and quantification accurate and reliable of plant-parasitic nematodes. The aim of this study was to analyze samples in qPCR to detect and quantify M. incognita, in the field samples, comparing different methods of extraction of DNA and its efficacy in establishing the number of individuals. For this purpose the effectiveness of different DNA methods of extraction was compared through the values of CT intervals. For standard curve and method comparisons, we used nematodes multiplied in a greenhouse and carefully separated in the specific quantities of the experiments. For the number of individuals experiment field samples previously counted under an optical microscope were used. The DNA extraction was made from 100 nematodes by the methods: CTAB, Phenol: Chloroform and commercial kit (PureLink® Genomic DNA Kit, Invitrogen). In the comparative analysis using the three methods of DNA extracting from 100 nematodes, it was observed that commercial kit and CTAB methods obtained CT values similar. The CTAB method of extraction, showed less variation in the repeats and greater linearity of standard curve in comparison with other methods tested. So, it was possible to quantify the samples through the CT value intervals, established from different numbers of individuals (1, 10, 25, 100, 250, 500 and 750), in field samples. This study demonstrated that qPCR technique is an alternative sensitive and reliable for the quantification of M. incognita to support laboratories of diagnose and field survey.

Os nematoides-das-galhas (Meloidogyne spp.) é o gênero de fitonematoide mais importante, são os patógenos mais comuns e destrutivos deste grupo. Eles produzem alguns dos sintomas mais drásticos nas plantas e podem reduzir significativamente o rendimento das culturas. Para conseguir implantar um método eficiente de manejo de nematoides parasitas de plantas, é necessária a identificação e quantificação precisa e confiável dos fitonematoides. O objetivo deste estudo foi analisar amostras em qPCR para detectar e quantificar M. incognita, em amostras de campo, comparando diferentes métodos de extração do DNA e sua eficácia no estabelecimento do número de indivíduos. Para este propósito, a eficácia de diferentes métodos de extração de DNA foi comparada através dos valores dos intervalos de Ct. Para comparações padrão de curvas e métodos, usamos nematoides multiplicados em casa de vegetação e cuidadosamente separados nas quantidades específicas dos experimentos. Para o número de indivíduos, foram utilizadas amostras de campo previamente contadas sob um microscópio óptico. A extração de DNA foi realizada a partir de 100 nematoides, pelos métodos: CTAB, Phenol: Clorofórmio e kit comercial (PureLink® Genomic DNA Kit, Invitrogen). Na análise comparativa utilizando os três métodos de extração de DNA a partir de 100 nematoides, observou-se que o kit comercial e os métodos de CTAB obtiveram valores de CT semelhantes. O método de extração CTAB apresentou menor variação nas repetições e maior linearidade da curva padrão em comparação com os demais métodos testados. O coeficiente de correlação (R2) da curva padrão foi de 0,98 indicando uma relação linear entre o valor de Ct e a quantidade de padrões de DNA variando de 90 a 0,00009 ng.µL-1. Assim, foi possível quantificar as amostras através dos intervalos de valores de CT, estabelecidos a partir de diferentes números de indivíduos (1, 10, 25, 100, 250, 500 e 750), em amostras de campo. Este estudo demonstrou que a técnica de qPCR é uma alternativa sensível e confiável para a quantificação de M. incognita, para apoiar laboratórios de diagnóstico e levantamentos de campo.

Influence of Meloidogyne incognita race 1 on the development of clones of Coffea canephora, variety "Jequitibá Incaper 8122" / Influência de Meloidogyne incognita raça 1 no desenvolvimento de clones de Coffea canephora, variedade "Jequitibá Incaper 8122"

Root-knot nematode is one of the most important phytosanitary problems for Conilon coffee, as it reduces productivity and is difficult to handle. We aimed at studying the infectivity and damage caused by M. incognita race 1 in the "Jequitibá Incaper 8122" intermediate maturity coffee variety. The experiment was conducted in a greenhouse, in completely randomized design, with five replicates. The clones composing the variety "Jequitibá Incaper 8122" were inoculated with 2,000 eggs + second-stage juveniles of M. incognita race 1. Uninoculated plants were the control. Evaluations were performed 180 days after inoculation, considering the plant height (H), stem diameter (SD), number of leaves (NOL), leaf area (LA), number of plagiotropic branches (NPB), number of nodes (NN), chlorophyll content (CHLO), shoot dry matter (SDM), root fresh matter (RFM), final population (FNP), and reproduction factor (NRF). The nematode reduced NOL in clones 208 and 209, NRF in clones 201, 203, 207 and 208, NN in clones 203, 207, 208 and 209, CHLO in clones 201, 204, 206, 207 and 209, SDM in clones 201, 203, 204 and 205 and RFM in clones 205 and 207. M. incognita race 1 FNP and NRF were larger in clones 208, 201, 207 and 203. Clone 202 had FNP and NRF equal to zero, being immune to the nematode. Clone 206 presented the lowest NRF value among clones parasitized by M. incognita.(AU)

O nematoide-das-galhas é um dos mais importantes problemas fitossanitários para o cafeeiro conilon, por reduzir a produtividade e ser de difícil manejo. Objetivou-se estudar a infectividade e os danos causados por M. incognita raça 1 na variedade de café conilon de maturação intermediária "Jequitibá Incaper 8122". O experimento foi conduzido em casa de vegetação, em DIC, com cinco repetições. Os clones que compõem a variedade "Jequitibá Incaper 8122" foram inoculados com 2.000 ovos + juvenis de segundo estádio de M. incognita raça 1. Plantas não inoculadas constituíram a testemunha. As avaliações foram realizadas 180 dias após a inoculação, sendo avaliados: altura da planta (ALT), diâmetro do caule (DCA), número de folhas (NFO), área foliar (AFO), número de ramos plagiotrópicos (NRP), número de nós (NN), teor de clorofila (CLO), massa seca da parte aérea (MSA), matéria fresca da raiz (MFR), população final (PFN) e fator de reprodução (FRE). O nematoide reduziu o NFO nos clones 208 e 209, NRP nos clones 201, 203, 207 e 208, NN nos clones 203, 207, 208 e 209, CLO nos clones 201, 204, 206, 207 e 209, MSA nos clones 201, 203, 204 e 205 e MFR nos clones 205 e 207. PFN e FRE de M. incognita raça 1 foram maiores nos clones 208, 201, 207 e 203; o clone 202 teve a PFN e a FRE igual a zero, apresentando-se imune ao nematoide. O clone 206 apresentou o menor valor de FRE entre os clones parasitados por M. incognita.(AU)

Effect of Pleurotus ostreatus (Jacq) and Trichoderma harzianum (Rifai) on Meloidogyne incognita (Kofoid & White) in tomato (Solanum lycopersicum Mill)

Two isolations of fungi from a bank of microorganisms in the Biological Sciences Laboratory at Escuela Superior Politécnica de Chimborazo were tested on the galling caused by Meloidogyne incognita in tomato seedlings grown in pots with substrate infested with a suspension of nematodes, with approximately 2000 juvenile stages (J2) from root galls of plants infested with M. incognita, taken from the Nematology laboratory of the Ecuadorian Agricultural Quality Assurance Agency (AGROCALIDAD). Pleurotus ostreatus was a fungus with nematicidal characteristics through production of toxins; while Trichoderma harzianum is a widely known fungus, although it is a plant growth promoter rather than a nematicide. The two fungi were formulated in wheat straw and rabbit manure. A complete randomized design (CRD) with three replications was used, with a chemical control (Fenamiphos) and an absolute control. Five grams of each formulation was applied per plant before the transplant. The number of galls in the roots, plant height, stem diameter, number of leaves and fresh and dry weight of the aerial part and roots of 180 tomato plants grown in greenhouse were evaluated at 60 days after transplant. The results showed that the two fungi reduced the number of galls and made it possible to obtain dry weights of the aerial and radicular part very close to the chemical control (10.09 and 3.39 g) with 8.68; 8.04; 2.96 and 3.25 g respectively. Besides Trichoderma harzianum proved to be a good promoter of root growth, therefore, the use of these bioformulates is a promising measure for the control of this phytonematode

Role of Synadenium grantii latex proteases in nematicidal activity on Meloidogyne incognita and Panagrellus redivivus / Papel das proteases do látex de Synadenium grantii na atividade nematicida sobre Meloidogyne incognita e Panagrellus redivivus

Abstract Synadenium grantii is a Euphorbiaceae plant commonly found in Brazil, known as Janaúba or Leitosinha, whose latex is traditionally used for several purposes. However, it is not known whether the nematicidal action of this plant latex occurs due to the action of proteases. The present work aims to evaluate the nematicidal activity of proteases from Synadenium grantii latex on Meloidogyne incognita and Panagrellus redivivus. S. grantii latex used in the present study was collected from specimens found in Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil. The drained latex was collected in Eppendorf microtubes and immediately stored on ice at 4 °C. After this extraction, the latex was frozen (-20 °C) during 2 hours, thawed at room temperature (25 °C) and centrifuged at 10,000 g at 4 °C for 30 minutes to remove larger particles and concentrate the proteases. After the centrifugation, assays of enzymatic activity were performed in order to know in which of the phases the enzymes were found. S. grantii latex presented protease, but no chitinase activity. The results show that there was a significant difference (p <0.01) between the treated and control groups, with 100% mortality of Meloidogyne incognita and 72% average mortality of Panagrellus redivivus. In addition, it was demonstrated that the nematicidal action occurred due to the action of the proteases, since the control was only differentiated from the treatment by the presence of the enzymes with biological activity.

Resumo Synadenium grantii é uma planta Euphorbiaceae comumente encontrada no Brasil, conhecida como Janaúba ou Leitosinha, e tem seu látex usado tradicionalmente para diferentes propósitos. Entretanto, não se conhece se a atividade nematicida da planta ocorre devido à ação de proteases. O presente trabalho tem como objetivo avaliar a atividade nematicida das proteases do látex de Synadenium grantii sobre Meloidogyne incognita e Panagrellus redivivus. O látex de S. grantii utilizado no presente trabalho foi coletado a partir de espécimes encontradas na Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil. O látex foi coletado em microtubos Eppendorf e imediatamente armazenado em gelo a 4 °C. Após esta extração, o látex foi congelado (-20 °C) durante 2 horas, descongelado à temperatura ambiente (25 °C) e centrifugado a 10000 g a 4 °C durante 30 minutos para a remoção de partículas e concentração das proteases. Após a centrifugação, foram realizados ensaios de atividade enzimática para saber em qual das fases as enzimas foram encontradas. O látex de S. grantii apresentou atividade de protease, mas nenhuma atividade de quitinase. Os resultados mostram que houve diferença significativa (p <0,01) entre os grupos tratados e controle, com 100% de mortalidade de Meloidogyne incognita e 72% de mortalidade média de Panagrellus redivivus. Além disso, foi demonstrado que a ação nematicida ocorreu devido à ação das proteases, uma vez que o grupo controle só foi diferenciado do tratamento pela presença das enzimas com atividade biológica.

Nematicidal potential of essential oils of Ageratum fastigiatum, Callistemon viminalis and Schinus terebinthifolius / Potencial nematicida de óleos essenciais de Ageratum fastigiatum, Callistemon viminalis e Schinus terebinthifolius

Some essential oils are rich in nematicidal compounds and can be used for the management of plant-parasitic nematodes. Laboratory and field studies aiming to evaluate the efficiency of this compounds are necessary. The objective of this research was to assess the nematicidal potential of essential oils from leaves of Ageratum fastigiatum and Callistemon viminalis, and green and mature fruits of Schinus terebinthifolius on the root-knot nematode Meloidogyne javanica. In laboratory, the essential oil of S. terebinthifolius green fruits reduced hatching by more than 80% and increased juvenile mortality by 300% when compared to Tween 20 + water. In the field, none of the essential oils controlled M. javanica in lettuce. In conclusion, the essential oil of S. terebinthifolius green fruits reduces the egg hatching and kills J2 of M. javanica in laboratory. In an infested field with an average of 555 J2/100 cm3 of soil, the application of the essential oils of S. terebinthifolius, C. viminalis and A. fastigiatum does not control M. javanica in lettuce.

Alguns óleos essenciais são ricos em compostos nematicidas e poderiam ser usados no manejo de fitonematoides. Estudos laboratoriais e de campo que visam avaliar a eficiência desses compostos são necessários. O objetivo desta pesquisa foi avaliar o potencial nematicida de óleos essenciais de folhas de Ageratum fastigiatum e Callistemon viminalis e frutos verdes e maduros de Schinus terebinthifolius sobre o nematoide de galhas Meloidogyne javanica. Em laboratório, o óleo essencial de frutos verdes de S. terebinthifolius reduziu mais de 80% a eclosão e aumentou em 300% a mortalidade de juvenis em comparação com Tween 20 + água. No campo, nenhum óleo essencial controlou M. javanica em alface. Em conclusão, o óleo de frutos verdes de S. terebinthifolius reduz a eclosão e mata J2 de M. javanica em laboratório. Em campo com infestação média de 555 J2/100 cm3 de solo, a aplicação dos óleos essenciais de S. terebinthifolius, C. viminalis e A. fastigiatum não controla M. javanica em alface.

Host status of crispy-leaf lettuce cultivars to root-knot nematodes / Reação de cultivares de alface do grupo crespa aos nematoides de galhas

Lettuce is the main leafy vegetable grown in the world, being the crispy-leaf lettuce type predominant. With consecutive cultivation in the same area, several factors may impair yield, highlighting the damage caused by root-knot nematodes, Meloidogyne spp. This study aimed at evaluating the reaction of twenty crispy-leaf lettuce cultivars to Meloidogyne incognita race 3, M. javanica and M. enterolobii. Three experiments were conducted, one for each nematode species. The experiments were carried out in a greenhouse, in pots with sterilized substrate. The design was completely randomized with five replications. Seedlings were inoculated with 1.000 eggs and second-stage juveniles of nematode per pot, on the day of transplantation of seedlings. The tomato 'Rutgers' was used as inoculum viability control for each specie tested. The variables evaluated were: reproduction factor (FR), total number of eggs and second-stage juveniles (NTOJ) and number of eggs and second-stage juveniles per gram of root (NOJGR), 60 days after inoculation. The results showed that the cultivars Veronica, Grand Rapids and Crespa para Verão are resistant to the three nematode species. The cultivars Thaís, SRV 2005 and Marisa are resistant to M. incognita race 3 and M. javanica. The cultivar Black Seed Simpson is resistant to M. enterolobii. The cultivars Vanda and Mônica SF 31 are resistant to M. incognita race 3. The cultivars Crespa, Rubia, Cinderela and Veneranda are resistant to M. javanica.

A alface é a principal hortaliça folhosa cultivada no mundo, sendo o tipo crespa mais comercializada. Com o cultivo consecutivo na mesma área, vários fatores podem prejudicar a produtividade, se destacando os danos causados pelos nematoides de galha, Meloidogyne spp. Este trabalho teve como objetivo avaliar vinte cultivares de alface, do grupo crespa, quanto a reação à Meloidogyne incognita, Meloidogyne javanica e Meloidogyne enterolobii. Foram realizados três ensaios, um para cada espécie de nematoide. Os experimentos foram conduzidos em casa de vegetação, em vaso com substrato autoclavado. O delineamento experimental foi em blocos casualizados, com cinco repetições. As plantas foram inoculadas com 1.000 ovos e eventuais juvenis de segundo estágio do nematoide, no dia do transplantio das cultivares. O tomateiro 'Rutgers' foi utilizado como padrão de viabilidade do inóculo de cada espécie de nematoide. As variáveis avaliadas foram: número total de ovos e juvenis do segundo estádio (NTOJ), fator de reprodução (FR) e número de ovos e juvenis de segundo estádio por grama de raízes (NOJGR) avaliadas 60 dias após a inoculação. Os resultados obtidos mostraram que as cultivares Verônica, Grand Rapids e Crespa para Verão foram resistentes as espécies M. enterolobii, M. incognita, M. javanica. As cultivares Thaís, SRV 2005 e Marisa foram resistentes as espécies M. incognita e M. javanica. A cultivar Black Seed Simpson foi resistente à M. enterolobii. Vanda e Mônica SF 31 foram resistentes à M. incognita. As cultivares Crespa, Rubia, Cinderela e Veneranda foram resistentes à M. javanica.

Evaluation of root-knot nematode disease control and plant growth promotion potential of biofertilizer Ning shield on Trichosanthes kirilowii in the field

Abstract Biofertilizer Ning shield was composed of different strains of plant growth promotion bacteria. In this study, the plant growth promotion and root-knot nematode disease control potential on Trichosanthes kirilowii in the field were evaluated. The application of Ning shield significantly reduced the diseases severity caused by Meloidogyne incognita, the biocontrol efficacy could reached up to 51.08%. Ning shield could also promote the growth of T. kirilowii in the field by increasing seedling emergence, height and the root weight. The results showed that the Ning shield could enhance the production yield up to 36.26%. Ning shield could also promote the plant growth by increasing the contents of available nitrogen, phosphorus, potassium and organic matter, and increasing the contents of leaf chlorophyll and carotenoid pigment. Moreover, Ning shield could efficiently enhance the medicinal compositions of Trichosanthes, referring to the polysaccharides and trichosanthin. Therefore, Ning shield is a promising biofertilizer, which can offer beneficial effects to T. kirilowii growers, including the plant growth promotion, the biological control of root-knot disease and enhancement of the yield and the medicinal quality.

Control potential of Meloidogyne javanica and Ditylenchus spp. using fluorescent Pseudomonas and Bacillus spp

ABSTRACT Plant Growth Promoting Rhizobacteria (PGPR) have different mechanisms of action in the development of plants, such as growth promotion, production of phytohormones and antibiotic substances and changes in root exudates. These help to control plant diseases. In order to evaluate the potential of microorganisms in the control of Meloidogyne javanica and Ditylenchus spp., five rhizobacteria isolated from rhizosphere of garlic cultivated in the Curitibanos (SC) region were tested. Hatching chambers were set on Petri dishes, in which were added 10 mL of bacterial suspension and 1 mL of M. javanica eggs suspension, at the rate of 4500, on the filter paper of each chamber. The same procedure was performed with 300 juvenile Ditylenchus spp. The experimental design was completely randomized, with four replications. The evaluations were performed every 72 h for nine days. The antagonized population of nematodes was determined in Peters counting chamber, determining the percentage hatching (for M. javanica) and motility (for Ditylenchus spp). Isolates CBSAL02 and CBSAL05 significantly reduced the hatching of M. javanica eggs (74% and 54.77%, respectively) and the motility of Ditylenchus spp. (55.19% and 53.53%, respectively) in vitro. Isolates were identified as belonging to the genera Pseudomonas (CBSAL05) and Bacillus (CBSAL02).