White mold, caused by Sclerotinia sclerotiorum, is a yield-limiting disease of soybean in Brazil. Uniform fungicide trials have been conducted annually since 2009. Data from 74 cooperative field trials conducted over a 10-year period were assembled. We selected five fungicides applied two times around flowering: dimoxystrobin plus boscalid (DIMO+BOSC), carbendazim plus procymidone (CARB+PROC), fluazinam (FLUZ), fluopyram (FLUO), and procymidone (PROC). For comparison, thiophanate-methyl (TMET) applied four times was also included as a low-cost treatment. Network models were fitted to the log of white mold incidence (percentages) and log of sclerotia mass data (grams/hectare) and to the nontransformed yield data (kilograms/hectare) for each treatment, including the untreated check. Back-transformation of the meta-analytic estimates indicated that the lowest and highest mean (95% confidence interval [CI]) percent reductions in incidence and sclerotia mass were 54.2 (49.3 to 58.7) and 51.6% (43.7 to 58.3) for TMET and 83.8 (79.1 to 87.5) and 87% (81.9 to 91.6) for CARB+PROC, respectively. The overall mean (95% CI) yield responses ranged from 323 kg/ha (247.4 to 400.3) for TMET to 626 kg/ha (521.7 to 731.7) for DIMO+BOSC, but the variance was significantly reduced by a binary variable (30% threshold) describing disease incidence in the untreated check. On average, an increment of 352 kg/ha was estimated for trials where the incidence was >30% compared with the low-disease scenario. Hence, the probability of breaking even on fungicide costs for the high-disease scenario was >65% for the more effective, but more expensive fungicide (FLUZ) than TMET. For the low-disease scenario, profitability was less likely and depended more on variations in fungicide cost and soybean price.

Resumo -Este trabalho teve por objetivos avaliar fungos em sementes de cedro e testar a patogenicidade de Fusarium sp. e Pestalotia sp. Para detecção de fungos, foram utilizados batata-dextrose-ágar e papel filtro. Para o teste de patogenicidade, utilizaram-se isolados de Fusarium sp. e de Pestalotia sp. Foi constatada a presença dos seguintes fungos nas sementes: Pestalotia sp., Fusarium sp., Phomopsis sp., Colletotrichum sp., Macrophomina sp. e Cladosporium sp. Os fungos de maior freqüência foram: Fusarium sp., Phomopsis sp. e Pestalotia sp. Observou-se decréscimo nos valores de emergência das plântulas oriundas das sementes inoculadas com Fusarium sp.Termos para indexação: Sementes florestais, Cedrella fissilis. Fungi Association with Cedar's Seeds and Fusarium sp. and Pestalotia sp. PathogenicitiesAbstract -This research had as main objectives the evaluation of cedar's seeds seed-borne fungi and the Fusarium sp. and Pestalotia sp. pathogenicities. For the fungi detection Potato Dextrose and Agar medium and Blotter test methods were used. For the pathogenicity tests, isolates of Fusarium sp. and Pestalotia sp. were used. The following fungi were observed: Pestalotia sp., Fusarium sp., Phomopsis sp., Colletotrichum sp., Macrophomina sp. and Cladosporium sp. The fungi observed in the highest frequencies were: Fusarium sp., Phomopsis sp. and Pestalotia sp. A reduction of the germination level was observed in seedlings from cedar's seed inoculated with Fusarium sp.

Biological control consists of using one organism to attack another that may cause economic damage to crops. Integrated Pest Management (IPM) is a very common strategy. The white mold produced by Sclerotinia sclerotiorum (Lib.) causes considerable damage to bean crops. This fungus is a soil inhabitant, the symptoms of which are characterized by water-soaked lesions covered by a white cottony fungal growth on the soil surface and/or the host plant. Possible biological control agents taken from plants are being investigated as phytopathogen inhibitors. These are endophytic microorganisms that inhabit the intercellular spaces of vegetal tissues and are often responsible for antimicrobial production. The objective of the present study was to select endophytic fungi isolated from comfrey (Symphytum officinale L.) leaves with in vitro antagonist potential against the phytopathogenic fungus S. sclerotiorum. Twelve isolates of endophytic fungi and a pathogenic strain of S. sclerotiorum were used in the challenge method. With the aid of this method, four endophytes with the best antagonistic activity against S. sclerotiorum were selected. Pathogen growth inhibition zones were considered indicative of antibiosis. The percentages of pathogenic mycelia growth were measured both with and without the antagonist, resulting in growth reductions of 46.7% to 50.0% for S. sclerotiorum. These analyses were performed by evaluating the endophytic/pathogenic mycelia growth in mm/day over an eight-day period of antagonistic tests.

-Most soybean pathogens are seed transmitted, deserving emphasis the fungus Sclerotinia sclerotiorum, which has been presenting worrying levels of field incidence in some soybean cropping areas in several Brazilian states. The objective of this study was to verify the efficiency of different methods for detecting S. sclerotiorum on soybean seeds artificially infected in the laboratory and from field production areas with a historical disease incidence. Seed samples of seven different cultivars collected from naturally infested fields, and one seed sample artificially inoculated in the laboratory were used. The following detection methods recommended in the literature were compared: Blotter test at 7 o C, 14 o C, and 21 o C; Rolled Paper; and Neon-S. Results demonstrated that these methods showed no repeatability and had a low sensitivity for detecting the pathogen in seeds from areas with disease incidence. They were effective, however, for its detection on artificially inoculated seeds. In the Blotter test method at 7 o C, there was a lower incidence of other fungi considered undesirable during seed analysis.Index terms: Glycine max, seed health, white mold, seed quality. Eficiência de métodos para detecção de

ABSTRACT:White mold caused by the fungus Sclerotinia sclerotiorum is an important disease in relation to soybean. The use of less susceptible genotypes can be a productive strategy in the management of this disease, and the development of an appropriate methodology for soybean inoculation is useful for the differentiation of disease-resistant genotypes. The present study aimed to assess the susceptibility of 77 soybean genotypes based on their reaction to oxalic acid, as well as to determine correlations between three traditional disease assay methods (detached leaf, non-wounded stem and straw tests) and the results of the oxalic acid assay. Oxalic acid susceptibility was assessed by using a wilting score scale. For the other methods, the severity of disease symptoms was assessed. To compare methodologies, the values obtained for the genotypes using each method were categorized into classes, and a severity index was used to represent individuals within each class. All the methods used were efficient for the differentiation of soybean genotypes in terms of susceptibility to S. sclerotiorum; however, the behavior of the genotypes depended on the inoculation method adopted. Even though no significant relationship was identified between the severities of the damage resulting from the methodologies, the rankings acquired from the methods strongly agreed. The oxalic acid method was the most rapid, the least laborious, and was the cheapest compared with the other methods that were used.