Evaluación de la mezcla de Burdeos, aceites y extractos vegetales sobre la mancha de fresa y la producción de frutos

Plant extracts and oils were assessed for strawberry leaf spot control in organic strawberry in the open field. For first cycle, treatments were extracts of rosemary (10 %) (Rosmarinus officinalis L.), garlic (Allium sativum L.) (0.01 %), rue (Ruta graveolens L.) (10 %), turmeric (Curcuma longa L.) (1 %), Bordeaux mixture (1 %), cotton (1.5 %) and canola oils (1 %), and water (control). For second cycle, Rosemary (20 %), rue (20 %), turmeric (2 %), canola oil (2 %), and water were used as treatments. A completely randomized block design with five replications was used. An analysis of variance was performed on the severity data, AUDPC and fruit production means were compared by the Scott-Knott and Tukey tests at 5% probability for first and second cycles, respectively. Canola oil (1 and 2 %) reduced disease symptoms in both cycles. Rosemary and rue extracts reduced just when disease severity was low. Cotton and canola oils and rosemary, rue and turmeric extracts increased strawberry fruit production.Se evaluaron extractos y aceites vegetales para el control de viruela en fresa orgánica en campo abierto. Los tratamientos en el primer ciclo fueron extractos de romero (Rosmarinus officinalis L.) (10 %), ajo (Allium sativum L.) (0,01 %), ruda (Ruta graveolens L.) (10 %), cúrcuma (Curcuma longa L.) (1 %), mezcla de Burdeos (1 %), aceites de algodón (1,5 %) y aceites de canola (1 %) y agua (control). En el segundo ciclo los tratamientos fueron romero (20 %), ruda (20 %), cúrcuma (2 %), canola aceite (2 %) y agua. El diseño experimental utilizado fue de bloques completamente al azar, con cinco repeticiones. Se realizó un análisis de varianza sobre los datos de severidad, el AUDPC y las medias de producción de frutos se compararon mediante la prueba de Scott-Knott y Tukey al 5 % de probabilidad para primer y segundo ciclos. El aceite de canola (1 y 2 %) redujo los síntomas de la enfermedad en los dos ciclos. Los extractos de romero y ruda se redujeron justo cuando la gravedad de la enfermedad era baja. Los aceites de algodón y canola y los extractos de romero, ruda y cúrcuma aumentaron la producción de frutos de fresa

In vitro control of phytopathogenic fungi and damping-off of tomato by Bacillus velezensis LABIM40 (CMRP 4489)

The in vitro antagonistic activity of Bacillus velezensis LABIM40 (strain CMRP 4489) was assessed against Alternaria linariae, Botryotinia squamosa, Colletotrichum lindemuthianum, Gibberella zeae, and Rhizoctonia solani. An experiment was conducted using treated seeds under growth chamber conditions to determine the impact of various LABIM40 formulations on tomato seedling growth and the biocontrol of damping-off caused by R. solani. The treatments included the use of LABIM40 cell suspension, LABIM40 cell-free supernatant (CFS), 10 times concentrated CFS (10× CFS), commercial products based on Bacillus amyloliquefaciens (CP_1) and Bacillus subtilis (CP_2), and water. The effects of these products were assessed on tomato seedlings grown in sterile substrate or substrate inoculated with R. solani. In a dual culture test, B. velezensis LABIM40 inhibited the mycelial growth of the aforementioned fungal pathogens by 46.6%, 67.4%, 64.7%, 49.0%, and 54.4%, respectively. The minimum inhibitory concentration against each fungus was determined using varying concentrations of CFS in potato dextrose agar medium, followed by a regression analysis of mycelial growth inhibition. Except for A. linariae, the logarithmic model provided the best fit in all cases. Tomato seedlings from seeds treated with 10× CFS in inoculated substrate exhibited a survival rate 57% higher than that exhibited by the control treatment. However, no growth promotion was observed in tomato plants from seeds treated with LABIM40 cells or its CFS metabolites. In summary, these findings highlight the antagonistic activity of B. velezensis LABIM40 against A. linariae, B. squamosa, C. lindemuthianum, G. zeae, and R. solani, as demonstrated by dual culture and CFS diffusion tests. This suggests its potential as a biocontrol agent for damping-off in tomatoes

Biological properties of turmeric

Curcuma spp. (turmeric) has been used since ancient days in popular medicine and gastronomy. Many of its bioactive compounds have just recently been identified and characterized as potential source of new medicines. In this review will relate aspects of cultivated turmeric (Curcuma longa L.), including taxonomy, chemical composition, production and processing, and biological activities such as the action against fungi, bacteria, nematodes, protozoa and viruses, including those of importance for human health, agriculture and food science

Respostas de genótipos de tomate suscetíveis e resistentes a Oidium neolycopersici e Alternaria solani, localização in situ de espécies reativas de oxigênio e atividade de enzimas relacionadas à defesa

To investigate plant defense responses on two Solanum section Lycopersicon genotypes differing in their resistance against Oidium neolycopersici and Alternaria solani, histopathology, generation and accumulation of reactive oxygen species (ROS) and expression of defenserelated enzymes [guaiacol peroxidase (GPOX), catalase (CAT), polyphenol oxidase (PPO), β-1,3-glucanase (GLU) and chitinase (CHI)] were studied after inoculation with those pathogens. To select one resistant and one susceptible genotype, we studied the fungus development on hosts in the case of tomato powdery mildew and we evaluated disease severity using a droplet inoculation method in the case of tomato early blight. CNPH 1287 (Solanum habrochaites syn. Lycopersicon hirsutum) and cv. 'Santa Cruz Kada' (Solanum lycopersicum syn. L. esculentum) were selected like as resistant and susceptible genotypes, respectively, against both pathogens. Two experiments were performed, where CNPH 1287 and Kada plants were inoculated with both pathogens and tissue samples collected for analysis at different time intervals. Oxidative explosion and hypersensitive response (HR) seem to be associated to resistance in CNPH 1287 (S. habrochaites) genotype against O. neolycopersici but not against A. solani. Higher constitutive levels and increased post-inoculation activity of β-1,3-glucanase and chitinase, increased activity of GPOX and PPO (enzymes involved with defense mechanisms) and CAT (enzyme involved with ROS scavenging) that were observed in resistant genotype CNPH 1287 after inoculation with O. neolycopersici were associated with simultaneously ROS accumulation and HR in the tissues. When inoculated with A. solani, CNPH 12987 showed similar changes in enzyme activity except for catalase, where no significant changes were observed. This agrees with the lower level of ROS accumulation during the A. solani pathogenesis. Gene-for-gene resistance with expression of HR and oxidative explosion were observed against the biotrophic pathogen O. neolycopersici. In the case of the necrotrophic pathogen A. solani, HR and ROS accumulation did not appear to play important roles in the resistance against this pathogen.Para investigar as respostas de defesa de dois genótipos do gênero Solanum Seção Lycopersicon com resposta diferencial frente a Oidium neolycopersici e Alternaria solani, avaliou-se a histopatologia, a produção e o acúmulo de espécies reativas de oxigênio (EROs) e a atividade de enzimas relacionadas à defesa [peroxidase de guaiacol (GPOX), catalase (CAT), polifenoloxidase (PFO), β-1,3-glucanase (GLU) e quitinase (QUI)] após inoculação com esses patógenos. Para selecionar um genótipo resistente e outro suscetível avaliou-se o desenvolvimento do fungo nos hospedeiros no caso de oídio e a severidade usando o método de inoculação por gota no caso da pinta preta. O genótipo CNPH 1287 (Solanum habrochaites sin. Lycopersicon hirsutum) e a cv. Santa Cruz Kada (S. lycopersicum sin. Lycopersicon esculentum) foram selecionados como resistente e suscetível, respectivamente, frente aos dois patógenos. Foram instalados dois experimentos, onde plantas de CNPH 1287 e cv Kada foram inoculadas com os patógenos separadamente e, posteriormente, coletadas em diferentes tempos após inoculação. O mecanismo de resistência do genótipo CNPH 1287 frente a O. neolycopersici esteve associado com resposta de hipersensibilidade (HR) e explosão oxidativa. Essa associação não foi detectada na resistência frente a A. solani. O aumento pós-inoculação da atividade de GPOX e PFO (enzimas envolvidas nos processos fisiológicos relacionados à defesa), da CAT (enzima envolvida na detoxificação das EROs) e os maiores níveis constitutivos e aumentos da atividade pós-inoculação das enzimas hidrolíticas QUI e GLU ocorridos em CNPH 1287 quando inoculado com O. neolycopersici são coerentes com o acúmulo concomitante de EROs e o desenvolvimento de HR nos tecidos. Mudanças similares na atividade dessas enzimas foram verificadas em CNPH 1287 na interação com A. solani. A exceção foi a ausência de resposta da CAT, coerente com o escasso acúmulo de EROs nos tecidos foliares observada durante a interação com A. solani. No caso do patógeno biotrófico O. neolycopersici, foi observada resistência do tipo gene-a-gene com manifestação de HR e explosão oxidativa. Já na interação com o patógeno necrotrófico A. solani, a magnitude da HR e acúmulo de Eros observada não indicam que cumpram um papel de importância na resistência frente a esse patógeno.xvi, 169

Oxidative burst and the activity of defense-related enzymes in compatible and incompatible tomato-Alternaria solani interactions

A produção de espécies reativas de oxigênio (EROs), a resposta de hipersensibilidade (HR) e a atividade das enzimas peroxidase de guaiacol, catalase, polifenoloxidase, B-1,3-glucanase e quitinase foram estudados em folhas de tomateiro resistente [CNPH 1287 (Solanum habrochaites syn. Lycopersicon hirsutum)] e suscetível [Santa Cruz Kada (S. lycopersicum syn. L. esculentum)] inoculadas com Alternaria solani. Essas folhas foram coletadas no momento da inoculação e às 4, 8, 12, 24, 48, 72, 96 e 120 h pós-inoculação. Os conídios germinaram igualmente na superfície foliar de ambos os genótipos sem orientação definida no crescimento dos tubos germinativos. A frequência de lesões causadas por A. solani foi menor no genótipo CNPH 1287 como consequência do menor número de apressórios formados nesse genótipo. O acúmulo de EROs foi observado em baixa frequência tanto no genótipo suscetível quanto no resistente. A HR foi observada nas células epidérmicas onde ocorreu penetração em ambos os genótipos. Os resultados deste trabalho indicam. Aumentos significativos na atividade de peroxidase de guaiacol, polifenoloxidase, B-1,3-glucanase e quitinase foram registrados no genótipo resistente. Estes resultados sugerem que, enquanto EROs e HR não parecem contribuir com a resistência de S. habrochaites frente a A. solani, as enzimas relacionadas à defesa cumprem um papel importante nas respostas de defesa deste genótipo.The production of reactive oxygen species (ROS), hypersensitive response (HR), and the activity of the enzymes guaiacol peroxidase, catalase, polyphenol oxidase, B-1,3-glucanase and chitinase, were studied in leaves of resistant [CNPH 1287 (Solanum habrochaites syn. Lycopersicon hirsutum)] and susceptible [Santa Cruz Kada (S. lycopersicum syn. L. esculentum)] tomato genotypes inoculated with Alternaria solani. Leaves were collected at the time of inoculation and at 4, 8, 12, 24, 48, 72, 96 and 120 hours post inoculation. Conidia germination occurred equally onto the leaf surface in both genotypes and germination tubes grew without apparent orientation. Lesion frequency was lower in CNPH 1287, and it was the consequence of a lower number of appressoria formed in that genotype. ROS were observed in low frequency in both genotypes. HR was observed in penetrated epidermal host cells also in both genotypes. It seems that ROS and HR would not contribute to the resistance of S. habrochaites to A. solani in this study. The activity of guaiacol peroxidase, polyphenol oxidase, B-1,3-glucanase and chitinase was significantly increased in the resistant genotype. These results suggest that defense-related enzymes but no oxidative burst play a role in the defense response of S. habrochaites to A. solani

Survival of <i>Xanthomonas vasicola</i> pv. <i>vasculorum</i> in Soil and in Corn Crop Residues under the Humid Subtropical Climate of Southern Brazil

Bacterial leaf streak caused by Xanthomonas vasicola pv. vasculorum (Xvv) is an emerging disease in several corn-producing regions around the world. In Brazil, there is a lack of information on the survival of this bacterium in soil and crop residues. Thus, the objective of this study was to determine the survival of Xvv in soil and also in infected corn crop residues under the humid subtropical climate of southern Brazil. The survival of Xvv in soil was initially investigated in sandy and clayey soils maintained at 20, 25 and 30 °C under controlled conditions. The survival of the bacterium under field conditions was studied in artificially infested clayey soil. The survival of Xvv in corn crop residues was investigated in infected residues maintained on the soil surface or buried in the soil at 20 cm deep. Under controlled conditions, regardless of the type of soil, the bacterium survived longer at 20 °C than at higher temperatures. The bacterium survived for 40 days in clayey soil kept at 20 °C and four days in sandy soil maintained at 30 °C. Under field conditions, the survival of Xvv in the soil was only for 48 h and in infected corn crop residues for up to 15 days in the samples maintained on the soil surface. In samples of infected corn residues buried in the soil, the bacterium was only detected at the time the experiment was set up. In general, the results obtained in this study revealed that Xvv survives for a short period of time in soil and in infected corn crop residues under humid subtropical conditions. Therefore, soil and corn residues may not be highly important sources of primary inoculum for the development of bacterial leaf streak on corn crops under these conditions

Biological control of bacterial spot of tomato by saprobe fungi from semi-arid areas of northeastern Brazil

Bacterial spot of tomato, caused by Xanthomonas spp., is a common disease in tomato fields that causes significant economic losses. Due to the difficulty with control of bacterial spot by conventional methods, new techniques such as biological control and induction of resistance are gaining prominence. This study aimed to select saprobe fungi from semi-arid regions of the Brazilian Northeast for the biological control of bacterial spot of tomato. To select the best isolates to control bacterial spot, a greenhouse experiment was initially conducted. Tomato plants (‘Santa Cruz Kada’) were treated with filtrates of 25 saprobe fungi and inoculated three days later with Xanthomonas euvesicatoria. Filtrates of Memnoniella levispora, Periconia hispidula, Zygosporium echinosporum, and Chloridium virescens var. virescens were selected as the most effective. Filtrates and volatile compounds from these four isolates were tested for their antibacterial activity in cultures of X. euvesicatoria and in tomato plants (‘Santa Cruz Kada’) inoculated with X. euvesicatoria. In vitro, the addition of nonvolatile fungal metabolites into the culture medium at 5% and 50% (v/v) inhibited bacterial growth by 28.9% and 53.8%, respectively. The volatile compounds produced by C. virescens var. virescens reduced the number of colony-forming units of X. euvesicatoria by 25.9%. In vivo, all treatments reduced from 62.4 to 71.3% the area under bacterial spot progress curve, showing the same control efficacy as the commercial resistance inducer used as a positive control (acibenzolar-S-methyl). Systemicity of the fungal filtrates was confirmed in a separate experiment, where application of the treatments exclusively to the third leaf decreased the severity of the disease on the fourth leaf (except for C. virescens var. virescens). These results show that M. levispora, P. hispidula, Z. echinosporum, and C. virescens var. virescens are potential biocontrol agents against bacterial spot of tomato. Further studies are necessary to elucidate the disease control mechanisms of saprobe fungi

Tratamento de sementes para o manejo de Meloidogyne javanica em soja

The objective of this study was to evaluate the efficacy of the active ingredient abamectin, either in isolation or in combination with fungicides and insecticides formulated for the industrial seed treatment, on the population of Meloidogyne javanica, tested under greenhouse and in vitro conditions. In both tests, the combination of the following treatments was assessed: abamectin; thiamethoxam; fludioxonil + metalaxyl-M + thiabendazole. Water was used as control for the in vitro assay, whereas under greenhouse conditions, controls were inoculated and not inoculated with M. javanica. The tests were conducted in a completely randomized design with six (in vitro) and ten (greenhouse) replicates. For in vitro studies the effect on hatching, motility, and mortality of juveniles of M. javanica was evaluated. Under greenhouse conditions, the soybean ‘BRS 133’ seeds were treated, and at 15, 30, and 60 days after inoculation (DAI) with M. javanica, plant measurements were recorded. The penetration of second stage juveniles (J2) was also evaluated at 15 DAI. At 30 DAI, galls, egg masses, nematodes/g of root, and final population were evaluated. At 60 DAI, the final population of nematodes in the roots was quantified. The treatments containing abamectin were the most effective in diminishing the hatching of juveniles. All treatments had an effect on nematode motility when compared to the control, and in the treatment containing only abamectin, total juvenile mortality was observed. In greenhouse conditions, at 15 DAI, the treated soybean plants had the highest root mass and shoot length, differing statistically from the inoculated control. All treatments reduced the number of nematodes per gram of root, differing from the control. At 30 DAI, treatment efficiency was observed in reducing the final population of M. javanica, particularly the treatments using abamectin, and abamectin + thiamethoxam + fludioxonil + metalaxyl-M + thiabendazole. However, at 60 DAI, the effect of the treatments on the population of M. javanica did not persist.O objetivo do trabalho foi avaliar a eficiência do ingrediente ativo abamectina, isolado ou em combinação com fungicidas e inseticidas formulados para o tratamento industrial de sementes, sobre a população de Meloidogyne javanica, in vitro e em casa de vegetação. Em ambos os ensaios, avaliou-se a combinação dos tratamentos: abamectina; thiamethoxam; fludioxonil + metalaxil-m + tiabendazol. Como controle utilizou-se água para o ensaio in vitro, e testemunhas inoculada e não inoculada com M. javanica, em casa de vegetação. Os ensaios foram realizados em delineamento inteiramente casualizado com seis (in vitro) e 10 (casa de vegetação) repetições. In vitro, avaliou-se o efeito sobre a eclosão, motilidade e mortalidade dos juvenis de M. javanica. Em casa de vegetação, as sementes da cultivar de soja BRS 133 foram tratadas e aos 15, 30 e 60 dias após a inoculação (DAI) com M. javanica foram realizadas mensurações fitométricas das plantas. Avaliaram-se, também, aos 15 DAI a penetração de juvenis de segundo estádio (J2); aos 30 DAI avaliou-se galhas, massas de ovos, nematoides/g de raiz e população final; e aos 60 DAI quantificou-se a população final de nematoides nas raízes. Os tratamentos contendo abamectina foram os mais eficientes em diminuir a eclosão dos juvenis. Todos os tratamentos apresentaram efeito na motilidade dos nematoides com relação à testemunha, sendo que no tratamento contendo apenas abamectina foi observada, também, a total mortalidade dos juvenis. Em casa de vegetação, aos 15 DAI, as plantas de soja tratadas apresentaram maior massa fresca de raiz e comprimento da parte aérea, diferindo estatisticamente da testemunha inoculada. Todos os tratamentos reduziram o número de nematoides por grama de raiz, diferindo da testemunha. Aos 30 DAI, observou-se eficiência dos tratamentos em reduzir a população final de M. javanica, destacando-se os tratamentos abamectina e abamectina + thiamethoxam + fludioxonil + metalaxil-m + tiabendazole. No entanto, aos 60 DAI o efeito dos tratamentos não se manteve sobre a população de M. javanica

Control del moho azul en poscosecha de manzana con productos naturales

Plant extracts for the control of plant disease are emerging as promising alternatives to the use of synthetic fungicides. The objective of this work was to study the effect of plant extracts and essential oils on naturally infected apple fruits with Penicillium spp. causal agent of blue mold. Apple fruits were immersed in citric and Azadirachta indica extracts at concentrations of 0.5 and 1.0% (v/v), stored at room temperature (25 °C and 90% RH) and analyzed at 21 days after the application of the treatments. Evaluated also the effect of fumigation of apple fruits with essential oils of Thymus vulgaris, Origanum vulgaris, Mentha piperita and Melaleuca alternifolia. Treated fruits were stored at 25±2 °C and 90±5% relative humidity for 20 days. Treated fruit with distilled water constituted the group controls. The higher values of incidence (100%), severity (99.98%) and the lowest percentage of disease control (4.56%) were observed in apple fruits treated with distilled water (group control). All treatments exhibited inhibitory effect on Penicillium spp. in apple fruits, however, A. indica and citric extracts, at concentrations of 1.0%, had a disease control of98.33% and 99.57%, respectively. There were no significant differences between the oils applied; except between these and the control. However, the treatments with essential oils were that exhibited the least incidence, severity and control of the disease. The results showed that essential oils showed good results, above 98.1% of control of blue mold disease in postharvest. It was demonstrated that extracts the different concentration and essential oils have antifungal activities and that they have a potential use as an alternative control in relation to chemical methods.El uso de los extractos vegetales con actividad antimicrobiana para controlar enfermedades en pre o poscosecha es una alternativa promisoria frente al uso de fungicidas sintéticos. El objetivo de este estudio fue evaluar el efecto de extractos vegetales y aceites esenciales en manzanas infectadas naturalmente con Penicillium spp., agente causal del moho azul. Se sumergieron manzanas en extractos de cítricos y de neem (Azadirachta indica) en concentraciones de 0,5 y 1,0% (v/v) y se almacenaron a 25 °C y 90% de humedad relativa. Después de 21 días se midió incidencia y severidad de la enfermedad. También se evaluó el efecto de los aceites esenciales de Thymus vulgaris, Origanum vulgaris, Mentha piperita y Melaleuca alternifolia por fumigación. La fruta se almacenó a 25±2 °C y 90±5% de humedad relativa durante 21 días. Frutos tratados con agua destilada estéril constituyeron el tratamiento control. Los frutos sin tratar presentaron los valores más altos de incidencia (100%) y severidad (99,98%) de moho azul, así como el menor porcentaje de control (4,56%). Todos los tratamientos mostraron efecto antifúngico de Penicillium spp, sin embargo, los extractos cítricos y de A. indica en la concentración de 1,0% proporcionaron los mayores niveles de control de la enfermedad (99,57% y 98,33%, respectivamente). Los frutos tratados con aceites esenciales mostraron menor incidencia, menor severidad y mayor control de la enfermedad. Se ha demostrado que el extracto y aceites esenciales estudiados tienen actividad antifúngica y potencial para uso en poscosecha como una alternativa al control químico