16 research outputs found

    EFEITO DE BACTÉRIAS SOBRE A BIOLOGIA DA TRAÇA DAS CRUCÍFERAS (Plutella xylostella) EM REPOLHO (Brassica oleraceae VAR. capitata) CV. MIDORI

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    The diamondback moth (DBM) Plutella xylostella (L.) (Lepidoptera: Plutellidae)is the most important cabbage pest in Brazil. Its control includes the use ofchemicals and Bacillus thuringiensis, individually or combined in an integratedpest management program. Plant growth-promoting rhizobacteria (PGPR)may be an important and new alternative in biological control of P. xylostella.This work aimed to study the effects of PGPR on the biology of DBM oncabbage through two different periods May to July 2000 (raining season) andFebruary to May 2001 (dry season). Cabbage seeds cv. Midori were immersedfor 30 min in a A580 = 0.52 or 108 CFU/ml bacterial suspensions, driedovernight, planted in polystyrene trays and transplanted field to three plots ina randomized design. At different days after transplanting (DAT) leavescollected randomly were brought to the laboratory and 8cm Ø-discs wereplaced in a Petri dish over filter paper. Ten 1st instar DBM larvae grown inlaboratory conditions were placed to feed on each leaf disc. Beginning onthe third day, leaf disks were changed daily until pupation. It was analyzedlarval mortality (LM) and pupal viability (PV), larval (LD) and pupal (LP)duration. In both experiments LM and PV were significantly increased andreduced by strains ENF14 (Enterobacter cloacae), EN5 (Alcaligenes piechaudii)and EN4 (Kluyvera ascorbata). Values for LM reached 60% compared with1.7% in control. In the raining season the protection was observed from 63to 74 DAT. In the dry season the effect was reduced and anticipated to theperiod from 45 to 60 DAT.A traça das crucíferas (DBM) Plutella xylostella (L.) (Lepidoptera: Plutellidae)é a praga mais importante do repolho no Brasil, podendo ser controlada pelouso de químicos e Bacillus thuringiensis, individualmente ou combinados emprograma de manejo integrado. Bactérias promotoras de crescimento deplantas (PGPR) podem ser uma importante nova alternativa para o controlebiológico de P. xylostella. Este trabalho objetivou estudar os efeitos de PGPRna biologia de DBM em repolho durante dois períodos de plantio Maio aJulho de 2000 (estação chuvosa) e Fevereiro a Maio de 2001 (estação seca).Sementes de repolho cv. Midori foram imersas durante 30 min em suspensõesbacterianas a A580 = 0,52 correspondendo a 108 unidades formadoras decolônias/mL, secas durante 12 h, semeadas em bandejas de poliestireno etransplantadas para 3 parcelas no campo em delineamento inteiramentecasualizado. Em diferentes dias após o transplantio (DAT) folhas de cadatratamento foram coletadas ao acaso e levadas ao laboratório, onde discos de8cm de diâmetro foram cortados e colocados em placas de Petri sobre papelde filtro. Dez larvas de DBM 1st instar, criadas em laboratório foram entãocolocadas para se alimentar sobre cada disco de folha. Após três dias, osdiscos foram trocados diariamente até a formação da pupa. Foram observadasmortalidade larval (LM) e viabilidade pupal (PV), duração larval (LD) e pupal(LP. Em ambos experimentos LM e PV foram significativamente elevadas ereduzidas pelos isolados ENF14 (Enterobacter cloacae), EN5 (Alcaligenes piechaudii)e EN4 (Kluyvera ascorbata). LM atingiu 60% comparada com 1,7% natestemunha. Na estação chuvosa, a proteção foi verificada entre 63 a 74 DAT. Na estação seca, o efeito foi menor e antecipado para o período entre45 a 60 DAT

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

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    ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

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    Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    LEVANTAMENTO DA INTENSIDADE DA PODRIDÃOMOLE EM ALFACE E COUVE-CHINESA EM PERNAMBUCO

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    Surveys of the intensity of soft rot in plantations of lettuce and Chinese cabbage were performed from January to May 2004 in mesoregions of the Mata and Agreste of the state of Pernambuco, Brazil. Disease prevalence of 42.9% was observed in lettuce and 100% in Chinese cabbage. The incidence of soft rot ranged from 0 to 22% in lettuce and 1 to 67% in Chinese cabbage. In lettuce higher intensity of soft rot was observed in areas with more than 17 years of cultivation; planted with cultivars "Cacheada", "Elba" and "Tainá"; with clay soil type; irrigated by hosing; and having poor drainage. Lower disease intensity was detected in areas of cultivars "Verdinha" and "Salad Bowl"; when coriander was the previous crop; and when seedlings wereproduced in trays. In Chinese cabbage higher intensity of soft rot was found in areas having more than 10 years of cultivation, and in plantations with more than 50 days of growth. The sole subspecies detected causing soft rot in all areas of lettuce and Chinese cabbage was Pectobacterium carotovorum subsp. carotovorum

    Biological control of mycotoxin-producing molds Controle biológico de fungos de armazenamento produtores de micotoxinas

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    Mycotoxins are produced by the secondary metabolism of many fungi and can be found in almost 25% of the world's agricultural commodities. These compounds are toxic to humans, animals, and plants and therefore, efforts should be made to avoid mycotoxin contamination in food and feed. Besides, up to 25% of all harvested fruits and vegetables are lost due to storage molds and/or mycotoxin contamination and many methods have been applied to mitigate these issues, but most of them rely on the use of fungicides. Although chemicals are often the first defensive line against mycotoxigenic fungi, the indiscriminate use of fungicides are awakening the public perception due to their noxious effects on the environment and human/animal health. Thus, there is an increasing public pressure for a safer and eco-friendly alternative to control these organisms. In this background, biological control using microbial antagonists such as bacteria, fungi and yeasts have been shown to be a feasible substitute to reduce the use of chemical compounds. Despite of the positive findings using the biocontrol agents only a few products have been registered and are commercially available to control mycotoxin-producing fungi. This review brings about the up-to-date biological control strategies to prevent or reduce harvested commodity damages caused by storage fungi and the contamination of food and feed by mycotoxins.As micotoxinas são produzidas pelo metabolismo secundário de várias espécies de fungos e podem ser encontradas em quase 25% das commodities agrícolas. Esses compostos são tóxicos a humanos, animais e plantas e, portanto, esforços para evitar a contaminação de micotoxinas em alimentos e rações devem ser feitos. Além disso, até 25% das frutas e legumes em pós-colheita são perdidos em decorrência do ataque de fungos de armazenamento e/ou contaminações por micotoxinas. Vários métodos têm sido aplicados para mitigar os problemas de micotoxinas, mas a maioria deles se baseia no uso de fungicidas. Embora os produtos químicos sejam, muitas vezes, a primeira estratégia de defesa contra fungos micotoxigênicos, o uso indiscriminado de fungicidas vem despertando a percepção pública, em razão de seus efeitos nocivos sobre o meio ambiente e à saúde humana/animal. Assim, existe uma crescente pressão pública em busca de alternativas mais segura e não nocivas ao meio ambiente para controlar estes organismos. Nesse contexto, o controle biológico utilizando antagonistas microbianos, tais como bactérias, fungos e leveduras têm mostrado ser um substituto viável para reduzir a utilização de produtos químicos. Apesar dos resultados positivos, usando os agentes de controle biológico, poucos produtos apenas foram registrados e estão comercialmente disponíveis para controlar fungos produtores de micotoxinas. Esta revisão traz estratégias de controle biológico para evitar ou reduzir danos em commodities agrícolas causadas por fungos de armazenamento e a contaminação de alimentos e rações por micotoxinas

    Endophytic fungi from Brachiaria grasses in Brazil and preliminary screening of Sclerotinia sclerotiorum antagonists

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    Fungal endophytes of Brachiaria, a nonhost of Sclerotinia sclerotiorum, may harbor species with antagonistic effects against this plant pathogen. The objective of this work was to investigate the diversity of endophytic fungi associated with different Brachiaria species and hybrids and evaluate their potential to inhibit the plant pathogen S. sclerotiorum. Stem samples from 39 Brachiaria spp. plants were collected in pasture fields and experimental areas of three states of Brazil resulting in 74 endophytes isolated. Twenty-eight species were identified by sequences of the Internal Transcribed Spacer (ITS) and 18S rDNA regions. Paraconiothyrium sp. was the most abundant endophyte, accounting for 24 % (14 isolates) of total, and it was isolated from B. ruziziensis, B. decumbens, B. humidicola, and B. brizantha. Phoma sorghina was the second most abundant taxon, followed by Sarocladium strictum, and Plenodomus sp. In vitro analyses showed that Paraconiothyrium sp., Sarocladium kiliense, Acremonium curvulum, Setophoma terrestris, Dissoconium sp., and Cladosporium flabelliforme exhibited antagonistic activity against S. sclerotiorum, with percentages of growth inhibition ranging from 25 to 60 (p < 0.05). Paraconiothyrium sp. BBXE1 (60 %), BBPB4.1 (60 %), BCMT4.1 (54 %), and S. kiliense (54 %) showed the highest values of Antagonism Percentages (AP). Therefore, fungi with inhibitory activity against S. sclerotiorum such as Paraconiothyrium sp. are naturally endophytic in Brachiaria grasses

    Contribution of organic amendments to soil properties and survival of Stenocarpella on maize stalk

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    The incorporation of organic matter to the soil not only improves nutrient content, but also reduces the survival of Stenocarpella, the causal agent of stalk rot, Diplodia ear rot, and grey leaf spot, in maize stubble. We evaluated the effect of organic waste incorporation on Stenocarpella survival in maize stalks, the activity of suppressiveness-related enzymes, and nutrient contents. We conducted the assays in the municipalities of Lavras and Sete Lagoas, Minas Gerais State, Brazil. Maize stalks infested with Stenocarpella were kept in field conditions for three months after poultry litter, swine manure, fish hydrolysate, compost sewage sludge, and urea application. Infested stalks, without residue amendment, were kept on surface or incorporated into the soil, representing negative and positive controls. Stenocarpella concentration in stalks was assessed using qPCR expressed as cycle threshold number. Sewage sludge, buried stalks, and stalks retained on the surface showed reduction of pathogen inoculum. Swine manure and urea did not reduce the quantity of DNA. In the experiment conducted in Lavras, poultry litter stimulated β-glucosidase, urease and hydrolysis of fluorescein diacetate activities when compared to the negative control. Sewage sludge, poultry litter, and swine manure increased Ca in the soil by 44 %, 38 % and 36 %, respectively, in the experiment conducted in Lavras. Poultry litter increased Ntotal three months after application. The results indicate that organic wastes are promising in improving nutrient content, activity of hydrolysis-related enzymes, but Stenocarpella inoculum dynamics should be taken into consideration when deciding on the specific organic amendment
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