Evolution and related pathogenic genes of Pseudodiploöspora longispora on Morchella based on genomic characterization and comparative genomic analysis.

True morels (Morchella) are globally renowned medicinal and edible mushrooms. White mold disease caused by fungi is the main disease of Morchella, which has the characteristics of wide incidence and strong destructiveness. The disparities observed in the isolation rates of different pathogens indicate their varying degrees of host adaptability and competitive survival abilities. In order to elucidate its potential mechanism, this study, the pathogen of white mold disease from Dafang county, Guizhou Province was isolated and purified, identified as Pseudodiploöspora longispora by morphological, molecular biological and pathogenicity tests. Furthermore, high-quality genome of P. longisporus (40.846 Mb) was assembled N50 of 3.09 Mb, predicts 7381 protein-coding genes. Phylogenetic analysis of single-copy homologous genes showed that P. longispora and Zelopaecilomyces penicillatus have the closest evolutionary relationship, diverging into two branches approximately 50 (44.3-61.4) MYA. Additionally, compared with the other two pathogens causing Morchella disease, Z. penicillatus and Cladobotryum protrusum, it was found that they had similar proportions of carbohydrate enzyme types and encoded abundant cell wall degrading enzymes, such as chitinase and glucanase, indicating their important role in disease development. Moreover, the secondary metabolite gene clusters of P. longispora and Z. penicillatus show a high degree of similarity to leucinostatin A and leucinostatin B (peptaibols). Furthermore, a gene cluster with synthetic toxic substance Ochratoxin A was also identified in P. longispora and C. protrusum, indicating that they may pose a potential threat to food safety. This study provides valuable insights into the genome of P. longispora, contributing to pathogenicity research.

Screening for resistance to four fungal diseases and associated genomic regions in a snap bean diversity panel.

Anthracnose, white mold, powdery mildew, and root rot caused by Colletotrichum lindemuthianum, Scletorinia sclerotiorum, Erysiphe spp., and Pythium ultimum, respectively, are among the most frequent diseases that cause significant production losses worldwide in common bean (Phaseolus vulgaris L.). Reactions against these four fungal diseases were investigated under controlled conditions using a diversity panel of 311 bean lines for snap consumption (Snap bean Panel). The genomic regions involved in these resistance responses were identified based on a genome-wide association study conducted with 16,242 SNP markers. The highest number of resistant lines was observed against the three C. lindemuthianum isolates evaluated: 156 lines were resistant to CL124 isolate, 146 lines resistant to CL18, and 109 lines were resistant to C531 isolate. Two well-known anthracnose resistance clusters were identified, the Co-2 on chromosome Pv11 for isolates CL124 and CL18, and the Co-3 on chromosome Pv04 for isolates CL124 and C531. In addition, other lesser-known regions of anthracnose resistance were identified on chromosomes Pv02, Pv06, Pv08, and Pv10. For the white mold isolate tested, 24 resistant lines were identified and the resistance was localized to three different positions on chromosome Pv08. For the powdery mildew local isolate, only 12 resistant lines were identified, and along with the two previous resistance genes on chromosomes Pv04 and Pv11, a new region on chromosome Pv06 was also identified. For root rot caused by Pythium, 31 resistant lines were identified and two main regions were located on chromosomes Pv04 and Pv05. Relevant information for snap bean breeding programs was provided in this work. A total of 20 lines showed resistant or intermediate responses against four or five isolates, which can be suitable for sustainable farm production and could be used as resistance donors. Potential genes and genomic regions to be considered for targeted improvement were provided, including new or less characterized regions that should be validated in future works. Powdery mildew disease was identified as a potential risk for snap bean production and should be considered a main goal in breeding programs.

Non-proteinogenic amino acids mitigate oxidative stress and enhance the resistance of common bean plants against Sclerotinia sclerotiorum.

White mold, caused by the necrotrophic fungus Sclerotinia sclerotiorum, is a challenging disease to common bean cultivation worldwide. In the current study, two non-proteinogenic amino acids (NPAAs), γ-aminobutyric acid (GABA) and ß-alanine, were suggested as innovative environmentally acceptable alternatives for more sustainable management of white mold disease. In vitro, GABA and ß-alanine individually demonstrated potent dose-dependent fungistatic activity and effectively impeded the radial growth and development of S. sclerotiorum mycelium. Moreover, the application of GABA or ß-alanine as a seed treatment followed by three root drench applications efficiently decreased the disease severity, stimulated plant growth, and boosted the content of photosynthetic pigments of treated S. sclerotiorum-infected plants. Furthermore, although higher levels of hydrogen peroxide (H2O2), superoxide anion (O2 •-), and malondialdehyde (MDA) indicated that S. sclerotiorum infection had markedly triggered oxidative stress in infected bean plants, the exogenous application of both NPAAs significantly reduced the levels of the three studied oxidative stress indicators. Additionally, the application of GABA and ß-alanine increased the levels of both non-enzymatic (total soluble phenolics and flavonoids), as well as enzymatic (catalase [CAT], peroxidases [POX], and polyphenol oxidase [PPO]) antioxidants in the leaves of S. sclerotiorum-infected plants and improved their scavenging activity and antioxidant efficiency. Applications of GABA and ß-alanine also raised the proline and total amino acid content of infected bean plants. Lastly, the application of both NPAAs upregulated the three antioxidant-related genes PvCAT1, PvCuZnSOD1, and PvGR. Collectively, the fungistatic activity of NPAAs, coupled with their ability to alleviate oxidative stress, enhance antioxidant defenses, and stimulate plant growth, establishes them as promising eco-friendly alternatives for white mold disease management for sustainable bean production.

Carpogenic germination of Sclerotinia sclerotiorum sclerotia in Brassica oleracea var gemmifera (VN: Brussels sprouts) in North Patagonia, Argentina.

In August 2018, symptoms of apical and basal rot resembling those caused by Sclerotinia sclerotiorum infection were observed in a commercial Brussels sprouts field in North Patagonia, Argentina. The incidence of apical and basal rot was 23.30% and 2.30%, respectively. Carpogenic germination of sclerotia was detected in shaded, highly humid soil areas. To our knowledge, this is the first report of carpogenic germination of sclerotia from S. sclerotiorum in North Patagonia.

Spongospora subterranea f. sp. subterranea Affects Plant Susceptibility to Subsequent Pathogen Infections Under Controlled-Environment Conditions.

Spongospora subterranea f. sp. subterranea (Sss) is a soilborne potato pathogen responsible for causing powdery scab on tubers and galls on roots, reducing root water uptake through colonizing root hairs, and vectoring of Potato mop-top virus (PMTV). However, effects of Sss on overall plant susceptibilities against subsequent infections of potato pathogens above ground have not been previously reported. This study aimed to investigate the effects of Sss on root and tuber disease expression, yield, and susceptibilities to subsequent late blight and white mold infections across six potato varieties. Sss-infected Silverton plants had 28.3% less total tuber yield and 29% fewer tubers compared to noninfected Silverton plants. We did not find a correlation across the varieties between root colonization and root gall formation. Sss-infected Silverton plants were more susceptible to hemibiotrophic late blight and less susceptible to necrotrophic white mold. Sss infection also increased susceptibilities of Goldrush and Atlantic plants to white mold. We also evaluated prevalence of asymptomatic Sss infections across the six varieties. Between 50 and 92% of the asymptomatic tubers tested positive for Sss DNA, depending on the variety. Further research is required to understand the possibility and extent of these asymptomatic infections to the spread of Sss in the field. These findings highlight the complexity of Sss-host interactions and give precedence that the lack of disease expression does not necessarily indicate resistance of a variety to Sss.

Double-Stranded RNA Targeting White Mold Sclerotinia sclerotiorum Argonaute 2 for Disease Control via Spray-Induced Gene Silencing.

Sclerotinia sclerotiorum, the causal agent of white mold infection, is a cosmopolitan fungal pathogen that causes major yield losses in many economically important crops. Spray-induced gene silencing has recently been shown to be a promising alternative method for controlling plant diseases. Based on our prior research, we focused on developing a spray-induced gene silencing approach to control white mold by silencing S. sclerotiorum argonaute 2 (SsAgo2), a crucial part of the fungal small RNA pathway. We compared the lesion size as a result of targeting each ∼500-bp segment of SsAgo2 from the 5' to the 3' end and found that targeting the PIWI/RNaseH domain of SsAgo2 is most effective. External application of double-stranded RNA (dsRNA)-suppressed white mold infection using either in vitro or in vivo transcripts was determined at the rate of 800 ng/0.2 cm2 area with a downregulation of SsAgo2 from infected leaf tissue confirmed by RT-qPCR. Furthermore, magnesium/iron-layered double hydroxide nanosheets loaded with in vitro- and in vivo-transcribed dsRNA segments significantly reduced the rate of S. sclerotiorum lesion expansion. In vivo-produced dsRNA targeting the PIWI/RNaseH domain of the SsAgo2 transcript showed increased efficacy in reducing the white mold symptoms of S. sclerotiorum when combined with layered double hydroxide nanosheets. This approach is promising to produce a large scale of dsRNA that can be deployed as an environmentally friendly fungicide to manage white mold infections in the field.

Wheat Rhizosphere-Derived Bacteria Protect Soybean from Soilborne Diseases.

Soybean (Glycine max [L.] Merr.) is an important oilseed crop with a high economic value. However, three damaging soybean diseases, soybean cyst nematode (SCN; Heterodera glycines Ichinohe), Sclerotinia stem rot caused by the fungus Sclerotinia sclerotiorum (Lid.) de Bary, and soybean root rot caused by Fusarium spp., are major constraints to soybean production in the Great Plains. Current disease management options, including resistant or tolerant varieties, fungicides, nematicides, and agricultural practices (crop rotation and tillage), have limited efficacy for these pathogens or have adverse effects on the ecosystem. Microbes with antagonistic activity are a promising option to control soybean diseases with the advantage of being environmentally friendly and sustainable. In this study, 61 bacterial strains isolated from wheat rhizospheres were used to examine their antagonistic abilities against three soybean pathogens. Six bacterial strains significantly inhibited the growth of Fusarium graminearum in the dual-culture assay. These bacterial strains were identified as Chryseobacterium ginsengisoli, C. indologenes, Pseudomonas poae, two Pseudomonas spp., and Delftia acidovorans by 16S rRNA gene sequencing. Moreover, C. ginsengisoli, C. indologenes, and P. poae significantly increased the mortality of SCN second-stage juveniles (J2), and two Pseudomonas spp. inhibited the growth of S. sclerotiorum in vitro. Further growth chamber tests found that C. ginsengisoli and C. indologenes reduced soybean Fusarium root rot disease. C. ginsengisoli and P. poae dramatically decreased SCN egg number on SCN-susceptible soybean 'Williams 82'. Two Pseudomonas spp. protected soybean plants from leaf damage and collapse after being infected by S. sclerotiorum. These bacteria exhibit versatile antagonistic potential. This work lays the foundation for further research on the field control of soybean pathogens.

Análise físico-química e atividades antifúngica e antioxidante do óleo essencial da flor de Curatella americana L / Physichochemical analysis, and antifungal and antioxidant activities of the essential oil of Curatella americana L. flower

Introdução: a espécie vegetal Curatella americana produz anualmente inflorescências com aroma adocicado rica em óleo essencial. Objetivo: avaliar as características físico-químicas, e atividades antifúngica e antioxidante do óleo essencial da flor de Curatella americana. Metodologia: as flores foram coletadas em quatro áreas de Cerrado no estado de Goiás; o rendimento de óleo essencial foi obtido através de hidrodestilação; as características físicas foram determinadas para densidade e solubilidade, a atividade antioxidante foi determinada pela redução do radical livre DPPH; a atividade antifúngica foi determinada por inibição das cepas de Candida, Sclerotinia sclerotiorum, Colletotrichum gloeosporioides e Aspergillus flavus. Resultados: o rendimento de óleo foi de 0,18%, densidade de 0,907 g mL-1, solubilidade positiva para EtOH 70%, atividade antioxidante de CI50 µL mL-1 1,95. Atividade de inibição fúngica apenas para Candida tropicalis na concentração de 8% com halo de antibiose de 10 mm. Sensibilidade discreta nas maiores concentrações de 25, 50 e 100 µL-1 para Aspergillus flavus e Sclerotinia sclerotiorum e baixa atividade de inibição para Colletotrichum gloeosporioides. Conclusão: o óleo essencial da flor de Curatella americana apresentou baixo rendimento, entretanto, alta eficiência na redução do radical livre DPPH. As atividades antifúngicas apresentaram bons resultados de inibição, entretanto, torna-se necessário a adição de outros óleos essenciais para aumento das taxas de inibição micelial.

Introduction: the plant species Curatella americana produces annual inflorescences with a sweet flavour rich in essential oil. Objective: to evaluate the physicochemical characteristics, antifungal and antioxidant activities of the essential oil of the Curatella americana flower. Methodology: the flowers were collected in four areas of Cerrado in the state of Goiás; the essential oil yield was obtained through hydrodistillation; the physical characteristics were determined for density and solubility, the antioxidant activity was determined by the reduction of the free radical DPPH; antifungal activity was determined by inhibiting the strains of Candida, Sclerotinia sclerotiorum, Colletotrichum gloeosporioides and Aspergillus flavus. Results: the oil yield was 0.18%, density 0.907 g mL-1, positive solubility for EtOH 70%, antioxidant activity of IC50 µL mL-1 1.95. Fungal inhibition activity only for Candida tropicalis at a concentration of 8% with a 10 mm antibiosis halo. Discrete sensitivity in the highest concentrations of 25, 50 and 100 µL-1 for Aspergillus flavus and Sclerotinia sclerotiorum and low inhibition activity for Colletotrichum gloeosporioides. Conclusion: The essential oil of the Curatella americana flower showed low yield, however, high efficiency in reducing DPPH free radical. Antifungal activities showed good inhibition results, however, it is necessary to add other essential oils to increase mycelial inhibition rates.

Chemical composition and in vitro inhibitory effects of essential oils from fruit peel of three Citrus species and limonene on mycelial growth of Sclerotinia sclerotiorum / Composição química e efeito inibitório in vitro dos óleos essenciais das cascas dos frutos de três espécies de Citrus e do limoneno sobre o crescimento micelial de Sclerotinia sclerotiorum

Abstract Essential oils (EO) from aromatic and medicinal plants generally perform a diverse range of biological activities because they have several active constituents that work in different mechanisms of action. EO from Citrus peel have an impressive range of food and medicinal uses, besides other applications. EO from Citrus reticulata, C. sinensis and C. deliciosa were extracted from fruit peel and analyzed by GC-MS. The major constituent of EO under evaluation was limonene, whose concentrations were 98.54%, 91.65% and 91.27% for C. sinensis, C. reticulata and C. deliciosa, respectively. The highest potential of inhibition of mycelial growth was observed when the oil dose was 300 μL. Citrus oils inhibited fungus growth in 82.91% (C. deliciosa), 65.82% (C. sinensis) and 63.46% (C. reticulata). Anti-Sclerotinia sclerotiorum activity of 90% pure limonene and at different doses (20, 50, 100, 200 and 300 μL) was also investigated. This monoterpene showed to be highly active by inhibiting 100% fungus growth even at 200 and 300 μL doses. This is the first report of the in vitro inhibitory effect of natural products from these three Citrus species and its results show that there is good prospect of using them experimentally to control S. sclerotiorum, in both greenhouse and field conditions.

Resumo Óleos essenciais de plantas aromáticas e medicinais geralmente exibem uma gama diversificada de atividades biológicas, pois possuem vários constituintes ativos que atuam por meio de vários mecanismos de ação. Os óleos essenciais das cascas de Citrus têm uma variedade impressionante de usos em alimentos, medicamentos entre várias outras aplicações. Os óleos essenciais (OE) de Citrus reticulata, C. sinenses e C. deliciosa foram extraídos das cascas dos frutos e analisados por CG-EM. O limoneno foi o constituinte majoritário encontrado nos óleos essenciais avaliados, nas concentrações de 98,54%, 91,65% e 91,27% para C. sinensis, C. reticulata e C. deliciosa, respectivamente. Os maiores potenciais de inibição do crescimento micelial foi observado na dose de 300 µL dos óleos. Os óleos de Citrus inibiram em 82,91% (C. deliciosa), 65,82% (C. sinensis) e 63,46% (C. reticulata) o crescimento do fungo. A atividade anti-Sclerotinia sclerotiorum do limoneno 90% puro e em diferentes doses (20, 50, 100, 200 e 300 µL) foi também investigada e este monoterpeno demonstrou-se altamente ativo inibindo 100% o crescimento do fungo inclusive nas doses de 200 e 300 µL. Este é o primeiro relato sobre o efeito inibitório in vitro dos óleos essenciais destas três espécies de Citrus e os resultados deste estudo mostram que existe uma boa perspectiva de uso destes produtos naturais experimentalmente para controlar o S. sclerotiorum tanto em condições de estufa como em condições de campo.

Detection of Sclerotinia sclerotiorum on soybean and common bean seeds by modified neon-s test / Detecção de Sclerotinia sclerotiorum em sementes de soja e de feijão pela técnica neon-s modificada

The Neon-S method has been used for detection of Sclerotinia sclerotiorum on soybean and common bean seeds since the 2010 crop season. However, this method can lead to identification of false-positives due to the presence of other fungi that change the medium pH. Thus, this study evaluated the effect of increasing incubation period on the reliability of Neon-S test in detecting S. sclerotiorum infection on soybean and common bean seeds. A randomized block design was set up with three replicates in a 3x3 factorial scheme, consisting of three detection methods (germination paper test, Neon-S, and modified Neon-S2) and three seed material (naturally infected common beans, naturally infected and artificially inoculated soybean seeds). The three methods were compared by evaluating 400 seeds per replication, after incubating them for seven days in Neon-S, for 15 days in Neon-S2, and for 30 days in germination paper, determining the presence of the fungus and of sclerotia adhered to the seeds. The data were submitted to the analysis of variance and the averages compared by the Tukey test at 5% probability. From 2008 to 2012, 637 lots were evaluated. Among the seed material, artificially inoculated soybean presented the greatest pathogen infection index. The germination paper test led to 2.8% of positive samples, contrasting 29.7% of Neon-S. The modified method Neon-S2 increased detection sensitivity of S. sclerotiorum in seed lots (31.2%); however, did not significantly differ from the Neon-S method, despite its greater averages. We concluded that detection of S. sclerotiorum by the Neon-S method can be optimized by incubation for 15 days (Neon-S2), due to the formation of sclerotia near the infect seeds which confirms the presence of the pathogen avoiding false-positive results.

O método de Neon-S tem sido utilizado para a detecção de Sclerotinia sclerotiorum em sementes de soja e de feijão desde a safra de 2010. Porém, esse método possibilita a leitura de falsos-positivos devido ao aparecimento de fungos que também alteram o pH do meio. O objetivo deste trabalho foi verificar se o aumento do período de incubação melhora a confiabilidade do teste Neon-S em detectar o patógeno S. sclerotiorum em sementes de soja e de feijão. Utilizou-se o delineamento experimental de blocos casualizados, em esquema fatorial 3x3, sendo três métodos de detecção (rolo de papel, Neon-S e o meio modificado Neon-S2) e três tipos de sementes (feijão infectado naturalmente e sementes de soja infectadas natural ou artificialmente), totalizando nove tratamentos, com três repetições. Os três métodos foram comparados avaliando 400 sementes por repetição: em meio Neon-S com incubação de sete dias, Neon-S2 com incubação de 15 dias e em rolo de papel por 30 dias, anotando-se a presença do fungo e de escleródios aderidos às sementes. Realizou-se a análise de variância dos dados e teste de comparação de médias (Tukey 5%). No período de 2008 a 2012, 637 lotes foram testados. Dentre os tipos de sementes, a soja inoculada artificialmente apresentou os maiores índices de infecção pelo patógeno. O teste de rolo de papel apresentou 2,8% de amostras positivas, enquanto o Neon-S 29,7%. O método Neon-S2 aumentou a sensibilidade de detecção de S. sclerotiorum nos lotes de sementes analisadas (31,2%); porém, não foi detectada diferença significativa comparativamente ao método Neon-S, ainda que com maiores médias. Conlui-se que a detecção de S. sclerotiorum pelo método Neon-S pode ser otimizada com a incubação por 15 dias (Neon-S2), em virtude da formação de escleródios próximos às sementes infectadas, o que confirma a presença do patógeno e evita a leitura de falsos-positivos.

Chemical composition and in vitro inhibitory effects of essential oils from fruit peel of three Citrus species and limonene on mycelial growth of Sclerotinia sclerotiorum

Abstract Essential oils (EO) from aromatic and medicinal plants generally perform a diverse range of biological activities because they have several active constituents that work in different mechanisms of action. EO from Citrus peel have an impressive range of food and medicinal uses, besides other applications. EO from Citrus reticulata, C. sinensis and C. deliciosa were extracted from fruit peel and analyzed by GC-MS. The major constituent of EO under evaluation was limonene, whose concentrations were 98.54%, 91.65% and 91.27% for C. sinensis, C. reticulata and C. deliciosa, respectively. The highest potential of inhibition of mycelial growth was observed when the oil dose was 300 L. Citrus oils inhibited fungus growth in 82.91% (C. deliciosa), 65.82% (C. sinensis) and 63.46% (C. reticulata). Anti-Sclerotinia sclerotiorum activity of 90% pure limonene and at different doses (20, 50, 100, 200 and 300 L) was also investigated. This monoterpene showed to be highly active by inhibiting 100% fungus growth even at 200 and 300 L doses. This is the first report of the in vitro inhibitory effect of natural products from these three Citrus species and its results show that there is good prospect of using them experimentally to control S. sclerotiorum, in both greenhouse and field conditions.

Resumo Óleos essenciais de plantas aromáticas e medicinais geralmente exibem uma gama diversificada de atividades biológicas, pois possuem vários constituintes ativos que atuam por meio de vários mecanismos de ação. Os óleos essenciais das cascas de Citrus têm uma variedade impressionante de usos em alimentos, medicamentos entre várias outras aplicações. Os óleos essenciais (OE) de Citrus reticulata, C. sinenses e C. deliciosa foram extraídos das cascas dos frutos e analisados por CG-EM. O limoneno foi o constituinte majoritário encontrado nos óleos essenciais avaliados, nas concentrações de 98,54%, 91,65% e 91,27% para C. sinensis, C. reticulata e C. deliciosa, respectivamente. Os maiores potenciais de inibição do crescimento micelial foi observado na dose de 300 µL dos óleos. Os óleos de Citrus inibiram em 82,91% (C. deliciosa), 65,82% (C. sinensis) e 63,46% (C. reticulata) o crescimento do fungo. A atividade anti-Sclerotinia sclerotiorum do limoneno 90% puro e em diferentes doses (20, 50, 100, 200 e 300 µL) foi também investigada e este monoterpeno demonstrou-se altamente ativo inibindo 100% o crescimento do fungo inclusive nas doses de 200 e 300 µL. Este é o primeiro relato sobre o efeito inibitório in vitro dos óleos essenciais destas três espécies de Citrus e os resultados deste estudo mostram que existe uma boa perspectiva de uso destes produtos naturais experimentalmente para controlar o S. sclerotiorum tanto em condições de estufa como em condições de campo.

New isolates of Trichoderma antagonistic to Sclerotinia sclerotiorum / Novos isolados de Trichoderma antagônicos a Sclerotinia sclerotiorum

Abstract Forty-nine isolates of Trichoderma from the Brazilian Midwest were evaluated for their antagonistic activity in vitro against Sclerotinia sclerotiorum (causal agent of white mold), which were then identified based on their nuclear ribosomal ITS sequences. Paired culture tests showed that all isolates exhibited some antagonism, with a maximum of 77% mycelial inhibition and complete inhibition of sclerotia production. Two isolates were found to be the most promising biocontrol agents, considering both antagonistic parameters (CEN1253 - T. koningiopsis and CEN1265 - T. brevicompactum). Five different species were identified: T. harzianum (23), T. spirale (9), T. koningiopsis (8), T. brevicompactum (7) and T. asperellum (2). These isolates are stored in the Embrapa Fungi Collection for Biological Control and the information obtained in the experiments will be incorporated into the database of biological assets within the genetic resources information system (Allele) and be made available for further studies.

Resumo Quarenta e nove isolados de Trichoderma obtidos no centro-oeste do Brasil foram avaliados quanto a sua atividade antagônica in vitro contra Sclerotinia sclerotiorum (agente causal do mofo branco) e identificados com base nas sequências ITS do DNA ribossômico nuclear. Os testes de cultivo pareado mostram que todos os isolados exibiram algum antagonismo, com um máximo de 77% de inibiação micelial e inibição total da produção de escleródios. Dois isolados se destacaram como os mais promissores, considerando ambos os parâmetros avaliados (CEN1253 - T. koningiopsis e CEN1265 - T. brevicompactum). Cinco espécies diferentes foram identificadas: T. harzianum (23), T. spirale (9), T. koningiopsis (8), T. brevicompactum (7) and T. asperellum (2). Estes isolados estão armazenados na Coleção de Fungos para Controle Biológico da Embrapa e as informações obtidas nos experimentos serão incorporadas na base de dados de ativos biológicos, no sistema de informações de recursos genéticos, e disponibilizados para estudos futuros.

Alternative products to control Sclerotinia sclerotiorum in soybean / Produtos alternativos no controle de Sclerotinia sclerotiorum na cultura da soja

The aim of this study was to evaluate different alternative products, foliar sprayed either alone or in combination with fungicide fluazinam, to control white mold in soybean at three locations: Arapoti, Mauá-da-Serra, and Pinhão, in Paraná state, southern Brazil. The following chemical products were used: sodium dichloroisocyanurate, benzalkonium chloride, pyroligneous extract, sodium hypochlorite, cobalt + molybdenum, sucrose, sodium bicarbonate and acibenzolar-S-methyl. Incidence, severity, yield, and number of sclerotia produced were analyzed. The majority of the variables did not follow the normal distribution of the data according to the Kolmogorov-Smirnov test; therefore, the use of non-parametric analysis was necessary. The analysis of all the treatments individually revealed no significant effects so it was decided to separate the analysis into the following groups of treatments: 'control', treatments using alternative products ('alternatives'), treatment only with fungicide ('fungicide') and treatments with alternative products and fungicide ('alternatives + fungicide'). In Arapoti, no significant differences for any variables were observed. In Mauá-da-Serra, the 'fungicide' and 'alternatives + fungicide' had the lowest incidence and number of sclerotia, with higher yield when compared to 'control' and 'alternatives'. No differences were observed for severity. In Pinhão, the 'fungicide' and 'alternatives + fungicide' were superior for incidence, number of sclerotia produced, and yield when compared to the 'control' and 'alternatives'. The 'alternatives + fungicide' showed significantly lower severity when compared to the control, 'alternatives' and 'fungicide' in Pinhão experiment. In conclusion, the alternative products applied in combination with fluazinam resulted in lower severity of white mold in soybean in the experiment conducted in Pinhão, and the application of fluazinam alone or in combination with alternative products, was efficient to control white mold in soybean in locations with high disease incidence.

O objetivo deste estudo foi avaliar diferentes produtos alternativos pulverizados via foliar, isoladamente ou em combinação com o fungicida fluazinam para o controle do mofo branco na cultura da soja, em três locais: Arapoti, PR, Mauá-da-Serra, PR e Pinhão, PR, Brasil. Os produtos utilizadas foram: dicloroisocianurato de sódio, cloreto de benzalcônio, extrato pirolenhoso, hipoclorito de sódio, cobalto + molibdenio, sacarose, bicarbonato de sódio e acibenzolar-S-metil. As variáveis analisadas foram incidência, severidade, rendimento e o número de escleródios produzidos. A maioria das variáveis não segue a distribuição normal dos dados conforme o teste Kolmogorov-Smirnov, assim sendo, o uso de testes não-paramétricos se fez necessário. A análise de todos os tratamentos individualmente não revelou efeitos significativos, onde optou-se por separar a análise em grupos de tratamentos, onde a testemunha foi denominada "controle"; os tratamentos com os produtos alternativos como "alternativos", o tratamento com o fungicida isolado como "fungicida" e os tratamentos com produtos alternativos e fungicida foi denominado "alternativos + fungicidas". Em Arapoti, não foram observadas diferenças estatisticamente significantes em nenhuma das variáveis analisadas. Em Mauá-da-Serra, os grupos 'fungicida' e 'alternativos + fungicida', apresentaram a menor incidência e número de escleródios, com maior rendimento quando comparados aos grupos 'controle' e 'alternativos'. Não foram observadas diferenças na severidade. Em Pinhão, os grupos 'fungicida' e 'alternativos + fungicida' foram estatisticamente superiores para incidência, número de escleródios produzidos e rendimento, quando comparados aos grupos 'controle' e 'alternativos'. O grupo 'alternativo + fungicida' apresentou severidade significativamente menor quando comparado aos grupos 'controle', 'alternativos' e 'fungicida' no experimento conduzido em Pinhão. Como conclusões, observou-se que os produtos alternativos aplicados em associação com o fungicida fluazinam proporcionaram menor severidade do mofo branco na cultura da soja no experimento conduzido em Pinhão, PR, e a aplicação do fungicida fluazinam isolado ou em associação com os produtos alternativos foi eficiente no controle do mofo branco na cultura da soja nos locais com alta incidência da doença.

Genetic and aggressiveness variation among Sclerotinia sclerotiorum dry bean isolates from Brazil fields / Variação genética e agressividade entre isolados de Sclerotinia sclerotiorum provindos de campos de feijão do Brasil

Sclerotinia sclerotiorum, infection of bean fields, has increased in Brazil. Fungicides application is the control strategy used due to lack of cultivars with complete disease resistance. To guide the use of isolates in resistance screening 25 S. sclerotiorum isolates from Brazilian dry bean fields were characterized using microsatellite markers, mycelial compatibility groups (MCGs) and aggressiveness. Microsatellite primer pairs were used to identify polymorphisms among the S. sclerotiorum isolates and MCGs were determined from interaction of all isolates grown sideby-side. Aggressiveness was derived from a straw test where fungal mycelium was placed over a cut bean stem and rated for disease progress. Data from microsatellite profiles grouped the 25 isolates into four clusters and seven MCGs were identified. No association among host cultivar and cluster or MCG of isolates was observed. For MCGs, 57% contained isolates sampled frequently over multiple locations and 43% contained isolates unique to locations. There were significant differences among isolates in aggressiveness within and between MCGs. The most aggressive isolates in resistance screening will be helpful in the identification of higher levels of resistance in bean germplasm/lines.

A infecção de Sclerotinia sclerotiorum em campos de feijoeiro tem aumentado no Brasil. A aplicação de fungicidas é a estratégia de controle utilizada devido à falta de cultivares com resistência completa á doença. Para orientar o uso de isolados visando resistência, 25 isolados de S. sclerotiorum coletados em campos de feijoeiro no Brasil foram caracterizados utilizando marcadores microssatélites, grupos de compatibilidade micelial (MCGs) e agressividade. Pares de primers de microssatélites foram utilizados para identificar polimorfismo entre os isolados de S. sclerotiorum e MCGs foram determinados a partir de interação dos isolados crescendo lado-a-lado. O teste de agressividade foi derivado a partir do straw test onde o micélio do fungo foi depositado sobre a haste cortada de feijoeiro e avaliado o progresso da doença. Os dados de microssatélites dos 25 isolados de S. Sclerotiorum foram agrupados em quatro grupos e identificados sete MCGs. Não foi observada associação entre a cultivar hospedeira e o cluster ou MCG dos isolados. Para MCGs, 57% continham isolados amostrados em vários locais e 43 % continham isolados de apenas um local. Houve diferença significativa entre os isolados na agressividade dentro e entre os MCGs. O isolado mais agressivo no screening de resistência será útil na identificação de níveis mais elevados de resistência em germoplasma/linhagens de feijoeiro.

Relationship between mycelial inoculum of Sclerotinia sclerotiorum and performance of sunflower seeds under controlled conditions / Relação entre inóculo micelial de Sclerotinia sclerotiorum e o desempenho de sementes de girassol em condições controladas

The cultivated area of sunflower in Brazil is expanding considerably over the last years as the result of the great interest in the biodiesel production derived from that crop. One consequence of that expansion is the occurrence of several diseases some of devastating nature in part of the growing areas with sunflower. This study evaluated the effects of the association of sunflower seeds infected by Sclerotinia sclerotiorum and the pathogen transmission rates from these infected seeds, considering some factors which may interfere in that interaction. Four inoculum potentials, two isolates of the cited fungus, two sunflower cultivars, 'Helio 250' and 'Helio 253' and two environmental temperatures, 20°C and 25°C, were used for the purpose in this work. Seed germination and health, emergence speed index, and plant populations were variables analyzed. From the results, increased levels of inoculum potentials led to gradual reduction of the mean values of germination, emergence rate index and plant populations, regardless the genotype, fungal isolates and temperatures. Transmission rates were higher at the highest levels of inoculum potential, the maximum reaching 80%. These results show the significance of S. sclerotiorum inoculum associated with sunflower seeds both in the establishment of plants in fields and also in spreading the pathogen inoculum between crop fields.

A área cultivada de girassol no Brasil tem se expandido consideravelmente, nos últimos anos, como resultado do elevado interesse na produção de biodiesel. Como consequência do crescimento da cultura, a ocorrência de várias doenças vem devastando as áreas plantadas com girassol. Este estudo avaliou os efeitos da associação de sementes de girassol infectadas por Sclerotinia sclerotiorum e as taxas de transmissão do patógeno a partir destas sementes infectadas, considerando os fatores que podem interferir nesta interação. Foram utilizados, neste trabalho quatro potenciais de inóculo, dois isolados de fungo, duas cultivares de girassol, 'Helio 250' e 'Helio 253', e duas temperaturas de crescimento, 20°C e 25°C. Sanidade e germinação das sementes, índice de velocidade de emergência e população de plantas foram as variáveis analisadas. A partir dos resultados, o aumento do nível do potencial de inóculo levou a uma redução gradual nos valores de germinação, índice de velocidade de emergência e população de plantas, independente da cultivar, do isolado fúngico e da temperatura. As maiores taxas de transmissão foram observadas nos níveis de potencial de inóculo mais elevados, atingindo níveis próximos de 80%. Estes resultados são indicativos sobre a importância do inóculo de S. sclerotiorum associado com sementes de girassol, tanto na disseminação do inóculo do patógeno, quanto como causa de possíveis danos em condições de campo.

Atividade de óleos e extratos vegetais sobre germinação carpogênica e crescimento micelial de Sclerotinia sclerotiorum / Activity of plant extracts on the carpogenic germination and mycelial growth of Sclerotinia sclerotiorum

A germinação carpogênica e o crescimento micelial de Sclerotinia sclerotiorum foram avaliados sob extratos metanólicos de Annona cacans, A. coriacea, A. crassiflora, A. dioica, A. sylvatica, Geophila repens, Guettarda viburnoides, Palicourea crocea, Schinus terebinthifolius e Trichilia silvatica, e sob as frações hexânica, hidrometanólica, clorofórmica e acetato de etila de A. cacans e óleo essencial de S. terebinthifolius. A concentração utilizada foi de 1.000 ppm para os extratos e de 100 ppm para as frações. Os extratos vegetais e as frações foram incorporados em meio ágar-água, que foi vertido em caixas gerbox com 20 escleródios. O crescimento micelial foi avaliado em óleo essencial de S. terebinthifolius, nas concentrações de 0, 100 e 1.000 ppm, incorporado ao meio BDA (Batata-Dextrose-Ágar). A germinação carpogênica apresentou-se menor sob os extratos de G. repens, P. crocea e S. terebinthifolius e sob as frações acetato de etila e clorofórmica de A. cacans. O número de apotécios formados por gerbox foi menor com o extrato de A. cacans. O crescimento micelial apresentou 10% de inibição na maior concentração do óleo essencial de S. terebinthifolius.(AU)

The efect of methanolic extracts of Annona cacans, A. coriacea, A. crassiflora, A. dioica, A. sylvatica, Geophila repens, Guettarda viburnoides, Palicourea crocea, Schinus terebinthifolius e Trichilia silvatica, and A. cacans hexane, ethyl etila, aqueous and chloroform fractions and the essential oil of S. terebinthifolius on mycelial growth and carpogenic germination of Sclerotinia sclerotiorum was evaluated. Te concentrations are 1,000 ppm for the extracts and 100 ppm for the fractions. To evaluate the germination, carpogenic, extracts and fractions were incorporated in agar-water that was poured into gerboxes where 20 sclerotia were distributed. To evaluate the mycelial growth, essential oil of S. terebinthifolius in concentrations of 0, 100 and 1,000 ppm was incorporated into the PDA and then poured into Petri dishes, to where pathogen mycelial discs were transferred. Extracts of G. repens, P. crocea and S. terebinthifolius and fractions ethyl acetate and chloroform of Annona cacans reduced the carpogenic germination of sclerotia of S. sclerotiorum and the extract of A. cacans reduced the number of apothecia formed. Mycelial growth showed 10% inhibition at the highest concentration of essential oil of S. terebinthifolius.(AU)

Influência de herbicidas e fungicidas na germinação carpogênica de escleródios de Sclerotinia sclerotiorum (Lib. ) de Bary / Influence of herbicides and fungicides in the carpogenic germination of sclerotia of Sclerotinia sclerotiorum (Lib. ) de Bary

Sclerotinia sclerotiorum é um fungo polífago apresentando mais de 400 espécies hospedeiras. No Brasil relata-se que sua ocorrência tenha aumentado a partir da safra 2003/2004 em função do uso de sementes infectadas, falta de rotação de culturas, entre outras causas. Nos EUA, há relatos que o aumento da doença também tenha ocorrido devido à redução no uso de herbicidas do grupo das triazinas na cultura do milho, em rotação. Alguns trabalhos relatam que esse herbicida atua na formação de apotécios anormais e na inibição da produção de ascósporos. Frente a isso o presente trabalho objetivou o estudo do efeito de 12 herbicidas e 5 fungicidas sobre a germinação carpogênica de S. sclerotiorum. O trabalho foi conduzido em laboratório na Universidade Estadual de Ponta Grossa. Em caixas tipo gerbox foram colocados 80 gramas de substrato e 20 escleródios. A aplicação foi realizada utilizando um volume de calda de 400 L ha-1. Após a aplicação as caixas foram acondicionadas em ambiente controlado (20°C e fotoperíodo de 12 horas). Os tratamentos utilizados foram: glifosato, lactofen, atrazina, setoxidim, diuron, diuron + paraquat, imazaquim, trifluralina, diclofop metílico, clorimuron etílico, metribuzim e imazetapir (herbicidas) e fluazinam, procimidone, carbendazim, dimoxystrobin + boscalid e tiofanato metílico (fungicidas). Aos 36 dias após a aplicação foi realizada uma contagem do número de escleródios germinados, número de estipes e número de apotécios por escleródio. Para os dados de germinação de escleródios, foi constatado que somente dimoxystrobin + boscalid apresentou germinação inferior a 70%. Os demais tratamentos apresentaram germinação superior a 83%. Para número de estipes formadas por escleródio foi constatado que todos os tratamentos apresentaram de duas a quatro estipes por escleródio. Foi observado que os tratamentos com dimoxystrobin + boscalid, tiofanato metílico e carbendazim apresentaram as menores taxas de diferenciação de estipes em apotécios, ou seja, constatou-se a formação de estipes inviáveis. No tratamento com dimoxystrobin + boscalid foi constatado uma viabilidade de apenas 34,56% de suas estipes. Os resultados aqui apresentados mostram que a aplicação antecipada desses tratamentos pode ser realizada visando atingir a fonte de inóculo (escleródios) no solo, reduzindo o potencial de infecção dos mesmos e consequentemente sua incidência sobre culturas.

Sclerotinia sclerotiorum is a pathogenic fungus with over 400 host species. In Brazil, it is reported that its occurrence has increased since the 2003-2004 growing season due to use of infected seed, lack of crop rotation, and several other factors. In the United States, reports suggest that the disease increase has occurred due to reduced use of herbicides from the triazine group on corn in rotation with soybean. Reports show that these herbicides affect S. sclerotiorum, causing the formation of abnormal apothecia and inhibiting ascospore production. Because of the possible linkage with herbicide use, a study was designed to examine the effect of 12 herbicides and 5 fungicides on the carpogenic germination of S. sclerotiorum. This work was performed at Universidade Estadual de Ponta Grossa. Eighty grams of sterilized field soil and 20 sclerotia, placed on the soil surface, were added to "gerbox" boxes. Chemicals were applied once using a rate of 400 L ha-1. After application, boxes were incubated in a controlled environment (20°C with a photoperiod of 12 hours). The treatments used were: glyphosate, lactofen, atrazine, sethoxydim, diuron, diuron + paraquat, imazaquin, trifluralin, diclofop methyl, chrlorimuron ethyl, metribuzin and imazethapyr (herbicides) and fluazinam, procymidone, carbendazim, dimoxystrobin + boscalid and thiophanate methyl (fungicides). The number of germinated sclerotia, stipes and apothecia was recorded 36 days after chemical application. For sclerotia germination, only dimoxystrobin + boscalid reduced germination below 70%. All other treatments had greater than 83% sclerotia germination. The number of stipes produced per sclerotium was constant for all treatments (two to four stipes per sclerotium). Dimoxystrobin + boscalid, thiophanate methyl and carbendazim had the lowest level of apothecia formation, which means inviable stipes were formed. For the treatment of dimoxystrobin + boscalid, only 34.56% of stipes developed into mature apothecia. The results of this study demonstrate that application of herbicides did not affect the sclerotia of S. sclerotiorum. Three of the five fungicide tested in this trial, dimoxystrobin + boscalid, thiophanate methyl and carbendazim, can reduce inoculum on the soil, which, in turn, would likely reduce disease incidence in the following crop.

Micobiota parasitária de escleródios de Sclerotinia sclerotiorum isolada de solos da fronteira oeste do Rio Grande do Sul / Parasitic mycoflora of sclerotia of Sclerotinia sclerotiorum isolated from soils of the western frontier of the state of Rio Grande do Sul, Brazil

O objetivo do presente trabalho foi identificar a diversidade da micobiota parasitária e o tempo decorrido até o início do parasitismo de escleródios de Sclerotinia sclerotiorum em solos da fronteira oeste do Rio Grande do Sul (RS). Foram coletados solos agrícolas e não agrícolas de cinco localidades na fronteira oeste do Rio Grande do Sul. O isolamento dos fungos foi realizado por meio do teste de iscas, sendo que as iscas foram os escleródios do fitopatógeno, os quais permaneceram enterrados no solo durante 15, 30 e 60 dias. Os fungos foram identificados em nível de gênero. Os gêneros fúngicos encontrados parasitando escleródios foram: Trichoderma, Penicillium, Aspergillus, Fusarium, Pythium (Cromista), Clonostachys rosea (Gliocladium), Chaetomium, Curvularia, Phytophthora (Cromista), Rhizopus, Lichtheimia (Absidia), Mucor, Acremonium, Periconia e Isaria.Observou-se que os escleródios foram parasitados pelos fungos até 15 dias depois de serem enterrados, e deste período em diante apenas a frequência de ocorrência dos fungos mudou. Concluiu-se que os gêneros fúngicos Isaria, Periconia, Acremonium, Lichtheimia (Absidia), Phytophthora, Curvularia e Chaetomium são encontrados em solos agrícolas e não agrícolas na fronteira oeste do RS, e não foram citados anteriormente em outros trabalhos. Existe diversidade de fungos parasitários de escleródios de S. sclerotiorum nos solos da fronteira oeste do RS, os quais podem ser utilizados em experimentos para compor um programa de controle biológico desse fitopatógeno. Os escleródios são parasitados pelos fungos durante até 15 dias, após os mesmos serem enterrados no solo.(AU)

The aim of this study was to identify the diversity of the parasitic mycoflora and to identify the necessary time until the beginning of the parasitism of sclerotia of Sclerotinia sclerotiorum in soils of the western frontier of the state of Rio Grande do Sul (RS), Brazil. Agricultural and non agricultural soils of five locations in the western frontier of Rio Grande do Sul were collected. The fungi isolation was performed by testing baits, and baits were the sclerotia of the phytopathogen, which remained buried in the soil for 15, 30 and 60 days. The fungi were identified at the genus level. The following fungal genera were found parasitizing sclerotia: Trichoderma, Penicillium, Aspergillus, Fusarium, Pythium (Cromista) Clonostachys rosea (Gliocladium), Chaetomium, Curvularia, Phytophthora (Cromista), Rhizopus, Lichtheimia (Absidia), Mucor, Acremonium, Periconia and Isaria. It was observed that the sclerotia were parasitized by fungi until 15 days after they had been buried. And after this period, only the frequency of occurrence of fungi has changed. It was concluded that the fungal genera Isaria, Periconia, Acremonium, Lichtheimia (Absidia), Phytophthora, Curvularia and Chaetomium are found both in agricultural and non-agricultural soils on the western frontier of RS, but they were not previously cited in other works. There is diversity of parasitic fungi of sclerotia of S. sclerotiorum in the soils of the western frontier of the RS, which can be used in experiments to compose biological control programs for this pathogen. The sclerotia are parasitized by fungi until 15 days after being buried underground.(AU)

Escala diagramática para avaliação da severidade de mofo branco em soja / Diagramatic scale to evaluation of white mold on soybean

O patógeno Sclerotinia sclerotiorum (Lib.) De Bary ocorre em sistemas de cultivo no Brasil por décadas, mas a avaliação da severidade da doença no campo ainda não foi devidamente estabelecida com o uso de escalas diagramáticas para avaliação de fungicidas em campo, produtos biológicos e resistência de germoplasma em programas de melhoramento ou cultivares. Este trabalho teve como objetivo propor uma escala diagramática obtida por meio do Programa Quant, via 500 fotos digitais em alta resolução (300 dpi) com obtidas por uma câmara Nikon D-90, equipada com lentes AFS-Nikor (18-105 mm), e ao mesmo tempo validá-la em ensaios de campo na cultura da soja. Para tanto foram implantados dois ensaios na fazenda do Grupo Eldorado ­ Uberlândia, com as cultivares de soja BRS-Favorita e P98Y11 (ambas RR nos anos 2010-2011 e 2011-2012, respectivamente). Os ensaios foram em blocos casualizados com seis tratamentos e quatro repetições e parcelas experimentais de 6 linhas com 6 m de comprimento. A área experimental continha em média 7-10 escleródios.m-2. Durante a condução dos experimentos foi avaliada presença de 2-3 apotécios.m-2. As avaliações de severidade nos ensaios de controle biológico com Trichoderma spp., nas safras 2010-2011 e 2012-2013 foram realizadas validando a escala entre dois grupos de 5 pessoas (cinco avaliadores com e cinco sem treinamento) e 10 imagens (níveis de severidade de 0 a 100 %). Esta escala foi utilizada nacionalmente nos ensaios de rede para o controle biológico e químico de mofo branco da soja.

The pathogen Sclerotinia sclerotiorum occurs in cropping systems in Brazil for decades, but the assessment of disease severity in the field has not been properly established using diagrammatic scales for evaluation of fungicides in field, biologics products and germplasm for resistance programs improvement or cultivars development. This work aimed to propose a diagrammatic established by Quant Program from 500 high resolution photos (300 dpi) from Nikon D 90 camera, lens AFS-Nikor (18-105 mm), while validating it in field trials when the effectiveness of biological products was being quantified in the 2010-2011 and 2011-2012 seasons. Therefore, we deployed two essays on the farm Eldorado Group - Uberlândia with cultivars (BRSFavorite and P98Y11, both RR in the years 2010-2011 and 2011-2012, respectively). Trials were in blocks with six treatments and four replications experimental plots of 6 rows with 6 m .As sowing rows spaced 45 cm with a population of plants 15 plants/m. The experimental area contained on average 7-10 escleródios.m-2. During the conduct of the experiments was assessed presence of 2-3 apotécios.m-2. During severity assessments were conducted in 2010-2011. This scale was used to validation between two groups from five persons (five trainers and five no trainers group by scale) and 10 levels of severity (0 to 100 %). After validation the scale that was used in the tests from nationally network for biological and chemical control of white mold on soybeans.

Ranqueamento de genótipos de soja com resistência parcial por diferentes métodos de inoculação de sclerotinia sclerotiorum submetidos à análise de correlação / Ranking of soybean genotypes with partial resistance from different inoculation methods of sclerotinia sclerotiorum and correlation analysis between procedures

A podridão branca da haste da soja ou mofo branco tornou-se a segunda doença em importância na cultura no Brasil. Pouco se conhece sobre a resistência de soja ao patógeno. O objetivo do trabalho foi avaliar e definir um método confiável na seleção de genótipos de soja resistentes ao mofo branco, causado por Sclerotinia sclerotiorum. O trabalho baseou-se em diferentes métodos de inoculação. Os testes foram conduzidos em ambiente controlado e à campo. Em condições de laboratório e câmara de crescimento sob condições ótimas de favorabilidade ótima e contínua ao patógeno e em campo com alternância de menor e maior favorabilidade ao mesmo. Para definir qual o melhor método de inoculação, como também os genótipos que possuem maior resistência parcial calcularam-se correlações pelo coeficiente de Spearman entre os métodos avaliados e métodos com o ranking geral das genótipos ou cultivares. O melhor método para avaliação da resistência de genótipos de soja ao mofo branco foi a inoculação realizada com ferimento no terço médio da planta onde estas se encontravam no final do florescimento e início de enchimento dos grãos, com discos de BDA e avaliadas 14 dias após a inoculação (rs=0,86) A cultivar que poderá ser considerada com padrão de resistência em outros estudos foi a Emgopa 316, sendo o padrão de suscetibilidade a BRSMG Garantia e BRSMG 68 Vencedora, sendo este último o genótipo mais suscetível ao mofo branco.

White mold or Sclerotinia stem rot is the second disease on soybeans in Brazil. In nowadays there is the lack of studies and inoculations methods to resistance in soybean genotypes his study evaluated and developed a reliable method for the selection of soybean genotypes resistant to white mold of soybean, also called Sclerotinia stem rot. The work was based on rating inoculations on the stem. The tests were conducted in two different environments, a controlled one, where plants were grown in a greenhouse and brought into the laboratory to be inoculated and incubated in a growth chamber where the temperature is favorable for fungal growth, and a field, where the pathogen is subjected to adverse environment conditions. Spearman´s coefficients of rank correlation were used to measure the correspondence between ranks of cultivar and ranks of the same cultivars in field experiments to establish the best inoculation method. The best method to evaluate soybean resistance was by wound inoculating the middle third of the plant when the plants were at the end of flowering and early grain filling, with PDA disks and evaluating 14 days later. This method was rs = 0.86, and the variety that can be considered as resistance standard in other studies was Emgopa 316, while the susceptible standards were BRSMG Garantia and BRSMG68 Vencedora. The most susceptible genotype was BRSMG 68 Vencedora.