ABSTRACT We report a case of urethral obstruction due to seminal vesiculitis in a Dorper sheep, with symptoms of anuria, rectal prolapse, orchitis/epididymitis, and uroperitoneum and biochemical tests indicating severe azotemia. The animal died due to advanced azotemia, and necropsy revealed kidneys with cortical and medullary necrosis, pyelonephritis of renal calyces, hydronephrosis, ruptured and necrotic bladder, and vesicular, bulbourethral, and ampoule accessory sex glands. There was prostate hyperplasia that revealed a large amount of pus in the cross section, which was also observed bilaterally in the epididymis and right testis. Morphotintorial and biochemical analyses of bacteria obtained from microbiological culture revealed Corynebacterium sp. and Escherichia coli. Infection, hyperplasia, and abscessation of accessory sex glands caused urethral compression, resulting in an obstructive condition, similar to urolithiasis, in addition to bacteremia. Hyperplastic seminal vesiculitis, although rare, must be included among the differential diagnoses of obstructive processes in the urinary tract of sheep.

RESUMO Relata-se um caso de obstrução uretral decorrente de vesiculite seminal em carneiro da raça Dorper, com quadro de anúria, prolapso retal, orquite/epididimite e uroperitôneo, com exames bioquímicos indicativos de severa azotemia. Devido ao quadro avançado de azotemia, o animal faleceu e, na necropsia, foi observado:: rins com necrose de cortical e medular, pielonefrite dos cálices renais e hidronefrose, bexiga rompida e necrosada, assim como glândulas sexuais acessórias vesiculares, bulbouretrais e ampola. Havia hiperplasia de próstata que, ao corte transversal, revelou grande quantidade de pus, que também foi observado bilateralmente no epidídimo e no testículo direito. As análises morfotintoriais e bioquímicas das bactérias obtidas a partir do cultivo microbiológico foram compatíveis com Corynebacterium sp. e Escherichia coli. A infecção, a hiperplasia e a abscedação das glândulas sexuais acessória, causaram compressão uretral, levando a um quadro obstrutivo, semelhante à urolitíase, somado à bacteremia. A vesiculite seminal hiperplásica, apesar de rara, deve ser incluída entre os diagnósticos diferenciais dos processos obstrutivos do trato urinário de carneiros.

Resumen La investigación tuvo como objetivo definir las mejores condiciones de extracción asistida por ultrasonido de los cálices de H. sabdariffa L. y la obtención de polvos microencapsulados, mediante secado por aspersión. Los extractos fueron analizados, considerando como variables: disolvente (agua y agua/etanol) y la relación temperatura/tiempo de extracción (25 °C/60 min y 60 °C/30 min). Para el secado se evaluaron las variables temperatura de entrada (150 °C; 190 °C) y la mezcla de encapsulantes goma arábiga (G) y maltodextrina (MD) (G40/ MD60; G60/MD40). Los parámetros utilizados para el análisis fueron: rendimiento, pH, °Bx, composición química (fenoles y antocianinas totales, CLAE-EM) y capacidad antioxidante (DPPH). La mejor condición para la extracción de polifenoles resultó ser con agua:etanol (80:20), a 60 °C y durante 30 min. Se identificó la presencia de ácidos fenólicos, glicósidos de flavonoles y las antocianinas (delfinidina-3-sambubiósido y cianidina-3-sambubiósido), como las señales de mayor intensidad. Con el secado por atomización a 150°Cy con G60/MD40, se logró el mayor contenido de fenoles totales y antocianinas, sin embargo, la capacidad antioxidante se favoreció a 150 °C y con G40/MD60. Las micropartículas obtenidas podrían valorarse como materia prima para la elaboración de fitofármacos o alimentos funcionales, considerando su fácil manipulación, posible estabilidad y su valor antioxidante.

Abstract The objective of the research was to define the best conditions for ultrasound-assisted extraction of H. sabdariffa L. calyces, and to obtain microencapsulated powders, by spray drying. The extracts were analyzed, considering as variables: extracting solvent (water and water/ethanol) and the temperature /extraction time ratio (25 °C/ 60 min and 60 °C/30 min). Inlet air temperature (150 °C; 190 °C) and the mixture of gum arabic (G) and maltodextrin (MD) as encapsulating agents (G40/MD60; G60/MD40) were the variables studied. The parameters used for the analysis were: yield, pH, °Bx, chemical composition (phenols and total anthocyanins, HPLC-MS), and antioxidant capacity (DPPH). The best polyphenols extraction conditions were water:ethanol (80:20), at 60 °C for 30 min. The presence of phenolic acids, flavonol glycosides, and anthocyanins (delphinidin-3-sambubioside and cyanidin-3-sambubioside) were identified as the signals of highest intensity. Inlet air temperature at 150 °C and G60/MD40 allowed the highest total phenols and anthocyanins content. However, the antioxidant capacity was better at 150 °C and G40/MD60. The microparticle obtained could be used as an ingredient for the preparation of phytopharmaceuticals or functional foods, considering their easy handling, and antioxidant capacity.

Resumo O objetivo da pesquisa foi definir as melhores condições para a extração assistida por ultrassom de H. sabdariffa L. calyces e obter pós microencapsulados, por meio de secagem por pulverização. Os extratos foram analisados considerando-se variáveis: menstruação (água e água/etanol) e a razão temperatura/tempo de extração (25 °C/60 min e 60°C/30 min). Para a secagem, os variais foram avaliados: temperatura de entrada (150 °C; 190 °C) e mistura dos encapsulantes goma arábica (G) e maltodextrina (MD) (G40/ MD60; G60/MD40). Os parâmetros utilizados para a análise foram: rendimento, pH, °Bx, composição química (fenóis e antocianinas totais, HPLC-MS) e capacidade antioxidante (DPPH). A melhor condição de extração acabou com a água: etanol (80:20), a 60 °C e por 30 min. A presença de ácidos fenólicos, flavonol glicosídeos e antocianinas (delfinidin-3-sambubiosídeo e cianidin-3-sambubiosídeo) foram identificados como sinais de maior intensidade. Com a secagem por pulverização a 150°Ce com G60/MD40, foi atingido o maior teor de fenóis e antocianinas totais, no entanto, a capacidade antioxidante foi favorecida a 150 °C e com G40/MD60. As microcápsulas obtidas podem ser utilizadas como matéria-prima na preparação de fitofarmacêuticos ou alimentos funcionais, considerando seu fácil manuseio, possível estabilidade e seu valor antioxidante.

OBJECTIVES: This study aimed to determine the effects of age, race/ethnicity, body mass index, and contraception on human chorionic gonadotropin (hCG) regression following the evacuation of a molar pregnancy. METHODS: This was a retrospective cohort study of 277 patients with molar pregnancies between January 1, 1994 and December 31, 2015. The rate of hCG regression was estimated using mixed-effects linear regression models on daily log-transformed serum hCG levels after evacuation. RESULTS: There were no differences in hCG half-lives among age (p=0.13) or race/ethnicity (p=0.16) groups. Women with obesity and hormonal contraceptive use demonstrated faster hCG regression than their counterparts (3.2 versus. 3.7 days, p=0.02 and 3.4 versus. 4.0 days, p=0.002, respectively). CONCLUSION: Age and race/ethnicity were not associated with hCG regression rates. Hormonal contraceptive use and obesity were associated with shorter hCG half-lives, but with unlikely clinical significance. It is important to understand whether the clinical characteristics of patients may influence the hCG regression curve, as it has been proposed as a way to predict the risk of gestational trophoblastic neoplasia.

RESUMO O objetivo do presente estudo foi determinar como o tempo de secagem e o estádio fenológico da planta influenciam na composição química e qualidade da silagem de azevém (Lolium multiflorum, Lam.). O delineamento experimental foi de blocos ao acaso, com seis tratamentos (vegetativo: cortar e ensilar; cortar + pré-secagem de 4 horas e ensilar; cortar + pré-secagem de 7 horas e ensilar; pré-florescimento: ensilagem, cortar e ensilar e pré-secagem de 4 horas; florescimento: cortar e ensilar) e quatro repetições, com quatro meses de conservação da silagem. Foram determinados: desaparecimento de massa após o corte, rendimento de massa seca, proteína bruta e frações fibrosas. Além disso, foram determinados na silagem: pH, lipídios totais, nitrogênio insolúvel em detergente neutro e ácido. O manejo empregado auxilia na desidratação da forragem, com perda na quantidade de nitrogênio no vegetativo. No pré-florescimento, essa perda não ocorre. O avanço do ciclo da forrageira ocasiona diminuição na quantidade de nutrientes na biomassa, entretanto a produção de forragem é aumentada. A silagem apresentou composição bromatológica semelhante à observada na massa verde de azevém, o que demonstra a eficiência do método de conservação. A ensilagem em estádios mais avançados é aconselhada quando se busca maior quantidade de biomassa ensilada, porém com qualidade inferior.

ABSTRACT The aim was how to define the effect of pre-drying time and the plant phase’s influence on chemical composition and quality of ryegrass silage. The experimental design was randomized blocks with six treatments (Vegetative: Cut and ensiled; cut + pre-drying 4 hours and ensiled and; cut + pre-drying of 7 hours and ensiled; Pre-flowering: Silage cutting and ensiled and pre-drying 4 hours Flowering:. cut and ensiled) and four repetitions. The silage was stowed for four months. It were determined the mass disappearance after cutting, dry matter yield, crude protein and fiber fractions. Moreover, it was determined on silage pH, total lipids and insoluble protein content. The management used aids in dehydration of fodder, resulting in losses on the amount of nitrogen on vegetative phase. For pre-flowering, this loss has not occur. The advance of fodder cycle causes a decrease in the amount of nutrients in biomass, but fodder yield increased. Ryegrass silage presented chemical composition similar to that observed on green mass of ryegrass, evinced the efficiency of fodder conservation method. The silage in more advanced phases is advised when seeking greater amount of ensiled biomass, but lower quality.

RESUMEN. We introduce the main results and techniques related to the constructions of the moduli spaces of linear series, limit linear series on curves and its relations with Abel maps. We start with a brief exposition of the theory of the linear series and its main consequences on smooth curves. Also, we examine two constructions of limits of linear series and their moduli spaces: Eisenbud and Harris types [14] and Osserman types [42]. In addition, we discuss the relation of the latter construction with Abel maps [22] and we present a new limits construction: Esteves-Nigro-Rizzo types [20,21] which generalize Eisenbud-Harris and Osserman constructions. Finally, we give a brief overview on further works related to these theories and their applications.

ABSTRACT. Se presentan los principales resultados y técnicas en la construcción de los espacios moduli de series lineales, series lineales límite sobre curvas y la relación de estos con los morfismos de Abel. Se inicia con una breve revisión de la teoría de series lineales y sus principales consecuencias sobre curvas suaves. Son examinadas dos construcciones de límites de series lineales y sus espacios moduli: los de tipo Eisenbud-Harris [14] y los de tipo Osserman [42]. Adicionalmente, es presentada la relación de esta última construcción con las fibras de los morfismos de Abel [22] y así mismo la construcción de los límites del tipo Esteves-Nigro-Rizzo [20,21] que generalizan los dos tipos de límites anteriores. Finalmente, una breve digresión presenta los avances actuales y aspectos de futuros desarrollos relacionados a estas teorías y sus aplicaciones.

ABSTRACT The parasite community structure in fish species of Chile have scarcely been analysed through time and locations, making it difficult to understand the spatio-temporal variation patterns. In this study, we investigated whether the endoparasitic community of three intertidal fishes in central Chile exhibited spatial or temporal changes. We collected a total of 954 individuals of Helcogrammoides chilensis, Gobiesox marmoratus and Scartichthys viridis in the intertidal rocky zone in localities close to the bays of Valparaíso (~32°45'S, 33°30'S) and of Concepción (~36°28'S, 36°41'S), during in 2013 and 2014. We analized the endoparasite community for each host according to their numerical descriptors, species composition and nestedness, comparing these communities as a function of both space and time. The average richness, abundance and diversity of the parasite infracommunity did not exhibit significant difference between localities (Valparaíso vs Concepción) for any of the host species. Only the parasitological descriptors of H. chilensis and G. marmoratus showed significant difference between years for Valparaíso. Similarity of parasite composition of each host species was low between years and geographical localities. The endoparasite infracommunity of S. viridis exhibited a nestedness pattern over time and space, unlike G. marmoratus that showed a random pattern over time and space. We concluded that spatio-temporal scales seem to be important factors for endoparasite community organization, but they affect different host species differently. The repeatability seems to be associated with the host species biology and the aggregate characteristics of the parasitic communities. However, our results suggest that other factors, such as environmental and/or ecological features, could impact on the community structure of parasites.

RESUMEN La estructura comunitaria de parásitos en peces de Chile ha sido poco abordada a través del tiempo y el espacio, impidiendo conocer los patrones de variaciones espacio-temporales. En este trabajo se estudia si la comunidad de endoparásitos de tres peces del intermareal de Chile central difiere entre localidades y años de muestreo, mediante descriptores parasitológicos, composición de especies y anidamiento. Se recolectaron 954 peces de tres especies, Helcogrammoides chilensis, Gobiesox marmoratus y Scartichthys viridis en pozas intermareales ubicadas en lugares cercanos a las bahías de Valparaíso (~32°45'S, 33°30'S) y de Concepción (~36°28'S, 36°41'S), durante 2013 y 2014. Las comunidades parasitarias fueron analizadas y comparadas por especie de hospedero, entre los rangos espaciales (localidades) y temporales (años). Los resultados muestran diferencias no significativas en los descriptores de abundancia, riqueza y diversidad entre localidades en los tres hospederos. Sin embargo, se observaron diferencias de estos descriptores entre años en la Bahía de Valparaíso para H. chilensis y G. marmoratus. La similitud de la composición parasitaria fue baja en cada especie hospedera al comparar entre años y localidades. Las infracomunidades de endoparásitos de S. viridis presentaron un patrón anidado en el tiempo y el espacio, a diferencia de G. marmoratus que presentó un patrón azaroso. En consecuencia, las escalas espacio-temporales son factores influyentes en la estructura de la comunidad de endoparásitos, pero su influencia difiere entre los hospederos. La repetitividad parece estar asociada a la especie de pez y las características agregadas de las comunidades de sus parásitos. Estos resultados indican que otros factores, ambientales y/o ecológicos, pueden influir en su estructura comunitaria.

Objectives: To compare hair cortisol concentrations (HCC) in drug-naïve first-episode psychosis (FEP) patients and healthy controls and to investigate the correlations between HCC and psychopathology. Methods: Twenty-four drug-naïve FEP patients and 27 gender- and age-matched healthy control subjects were recruited. The Structured Clinical Interview for DSM-IV (SCID-1) was used to confirm/rule out diagnoses, and the Positive and Negative Symptoms Scale (PANSS) was used to assess symptom severity. Hair samples (2-3 cm long) obtained from the posterior vertex region of the scalp were processed in 1-cm segments considering a hair growth rate of 1 cm per month. The 1-cm segments were classified according to their proximity to the scalp: segment A was the closest to the scalp and referred to the month prior to inclusion in the study. Segments B and C referred to the 2nd and 3rd months prior to the time of evaluation respectively. Hair steroid extraction was performed using a known protocol. Results: Two-way analysis of covariance (ANCOVA) with gender and age as covariates revealed a group effect (F1.106 = 4.899, p = 0.029) on HCC. Between-segment differences correlated with total PANSS score and with PANSS General Psychopathology subscale and total score. Conclusions: Our findings suggest that hypothalamic-pituitary-adrenal (HPA) axis, as assessed by long-term (3-month) cortisol concentration, is abnormal in the early stages of psychosis. The magnitude of changes in HCC over time prior to the FEP correlates to psychopathology. HPA axis abnormalities might begin prior to full-blown clinical presentation requiring hospital admission.

ResumenLa estructura de la comunidad de parásitos, determinada mediante análisis de anidamiento, varía considerablemente en función de la especie hospedera y el tamaño corporal de la misma. El patrón anidado es aquel en el que comunidades pobres en especies constituyen subunidades de comunidades de mayor riqueza, lo cual también se observa en las comunidades de parásitos. Existen grandes diferencias de riqueza y abundancia de parásitos en función del tamaño del hospedero. Por lo tanto, en este estudio determinamos, mediante análisis de anidamiento, si la estructura de la comunidad de parásitos de peces del intermareal, se relaciona con la longitud corporal de los hospederos y los descriptores parasitológicos. Se recolectaron 2 435 individuos de cinco especies de peces del intermareal rocoso de Chile central (32º02'-33º57' S y 70º30'- 70º30' W); Helcogrammoides chilensis, Scartichthys viridis, Auchenionchus microcirrhis, Gobiesox marmoratus y Sicyases sanguineus. Cada especimen fue revisado con respecto a sus parásitos y medido en su longitud total (LT). Las cinco especies muestreadas fueron clasificadas en función de la longitud corporal (LT) en tres rangos, cada uno de los cuales constituye una infracomunidad del estudio, y para la que se calculó el índice de anidamiento. Se emplearon los modelos NTCP (Nestedness Temperature Calculator Program) y NODF (Nestedness metric based on the Overlap and Decreasing Fill), utilizando la presencia/ ausencia de especies parásitas. También se empleó el modelo WNODF (Weighted - NODF) utilizando la abundancia de parásitos por especie. Así mismo, se calculó la riqueza total de especies, el promedio de riqueza, abundancia, diversidad y dominancia a nivel de la infracomunidad, para relacionarlos con los índices de anidamiento. Las infracomunidades de parásitos de la mayoría de las especies presentaron patrones de anidamiento, excepto en G. marmoratus y H. chilensis, en algunos de sus rangos de LT. No se encontró una relación directa entre el índice de anidamiento y la LT de los peces. Sin embargo, se observaron correlaciones directas de los índices de anidamiento con la riqueza promedio, abundancia y la diversidad infracomunitaria de parásitos, pero no con la riqueza total, que mostró una correlación inversa con la LT del hospedero. Además, se detectó anidamiento en la comunidad componente de parásitos en todas las especies de peces. Concluimos que las comunidades de parásitos de peces provenientes de la zona intermareal son estructuradas y predecibles, y se encuentran vagamente condicionadas por la LT de los hospederos y las características agregadas de los parásitos, especialmente a un nivel infracommunitario.

AbstractStructure and richness of parasite communities varies substantially among species and body sizes of hosts, which can be determined by analyzing the nestedness. The nestedness pattern is originated when depauperate communities are subsets of those found in communities with greater species richness, and has normally used to study parasite communities. Therefore, in this study we determined whether the structure of parasite communities of the intertidal fish, of central Chile, relates to host lengths and parasitological descriptors, by the use of nested subset analyses. We collected 2 435 individuals of five fish species from the intertidal rocky zone of central Chile (32º02'-33º57' S - 70º30'-70º30' W): Helcogrammoides chilensis, Scartichthys viridis, Auchenionchus microcirrhis, Gobiesox marmoratus, and Sicyases sanguineus; each specimen was analyzed for parasites and its total body length (LT) was measured. The total species richness, average richness, abundance, diversity, and dominance of parasites infracommunity (all parasites in a host specimen) were calculated. Each fish species was classified into three LT ranges, to calculate the indices of nestedness and average of these parasitological descriptors in each LT range. We used the models given in the NTCP (Nestedness Temperature Calculator Program) and NODF (Nestedness metric based on Overlap and Decreasing Fill), considering the presence or absence of parasite species; we also used WNODF (Weighted-NODF) model for parasite abundances. The average of parasitological descriptors and LT of each host species, as well as the indices of nestedness were also calculated and related one another, considering the infracommunity and component community levels. The parasite infracommunity of most fish species exhibited a nestedness pattern structure, with the exception of G. marmoratus and H. chilensis, in some of the LT ranges. No relationship between the nestedness indices and fish LT was found. Nevertheless, direct correlations were observed among nestedness indices, average of richness, abundance and diversity of parasite infracommunity, and an inverse correlation with the parasite total richness (per LT range). Moreover, the nestedness pattern was present in all host species. We concluded that the parasite communities of intertidal fish are structured and predictable, and determined only minimally by the host LTs and the aggregated characteristics of the parasites, particularly at the infracommunity level. Rev. Biol. Trop. 63 (4): 995-1005. Epub 2015 December 01.

For the process of hydrazine electrooxidation over the layer of ferrocene-carbonylic derivative, the electroanalytic functionmechanism has been suggested. Also there has been developed and analyzed (by means of linear stability theory and bifurcation analysis) the mathematical model, capable to describe the processes in the system. The results of the modeling have been compared with experimental and theoretical for analogous systems

Para o processo da eletrooxidação da hidrazina sobre a camada do composto carbonílico derivado de ferroceno, foi sugerido o mecanismo do desempenhoeletroanalítico. Para ele, também foi desenvolvido e analisado (por meio da teoria de estabilidade lineal e análise de bifurcações) o modelo matemático, capaz de descrever os processos no sistema. Os resultados da modelagem foram comparados com os experimentais, bem como com os teóricos, observados para sistemas análogos.

O objetivo deste estudo foi avaliar a ocorrência da infecção pelo vírus Maedi-Visna em ovinos criados nas microrregiões de Botucatu, Campinas, Piedade e São Paulo do Estado de São Paulo. As amostras de soro sanguíneo foram colhidas de 226 ovinos e foi realizada a técnica de imunodifusão em gel de ágar para a detecção de anticorpos antivírus Maedi-Visna e verificou-se que nenhuma das amostras testadas foi sororeagente. Dessa forma, faz-se necessário um estudo mais amplo no estado, a fim de se confirmar a baixa ocorrência e importância da enfermidade no estado.

The purpose of the study was to evaluate the occurrence of infection with maedi-visna virus in sheep raised in the regions of Botucatu, Campinas, Piedade and São Paulo, state of São Paulo, Brazil, that showed symptoms of the disease. Blood serum samples collected from 226 sheep were submitted to the agar gel immunodiffusion technique for detection of antibodies against maedi-visna virus, and none of the samples tested was serum reactive. In conclusion, the maedi-visna virus has low frequency in animals raised in the regions studied.

In the present paper we studied the recoveries of glyphosate, N-(phosphonomethyl)glycine (GLY) and its major metabolite, (aminomethyl)phosphonic acid (AMPA) in soil using national (Brazilian) ion-exchange resins, derivatization by a mixture of trifluoroacetic anhydride and trifluoroethanol and analyses by GC-MS. The quantification limits were 12 ng.g-1 for both compounds and the methodology showed a range of recuperation from 85 to 94% with coefficients of variation (CV) ranging from 4.07 to 6.91% for GLY. For AMPA, the mean recoveries ranged from 87 to 102% with CVs ranging from 5.81 to 6.99%. Additional studies showed that, due to the instability of the derivatized compounds, they must be analysed keeping constant time between derivatization and analysis, preferably less than 24 h.

A partir de 1995, uma nova doença foi observada em tubérculos de batata provenientes da região de Tulelake, Califórnia, USA, com sintomas que sugeriam a doença conhecida como sarna prateada, causada por Helminthosporium solani. Assim, os objetivos deste trabalho foram: a) isolar, identificar a natureza do agente causal dessa doença de batata na Califórnia; b) investigar a distribuição de H. solani nos campos de batata de Tulelake e o seu potencial de inóculo no momento da colheita; c) caracterizar o progresso da doença e populações de esporos de H. solani em condições de armazenamentos comerciais. Em armazéns comerciais, os principais gêneros de fungos associados aos tubérculos doentes foram Helminthosporium solani, Colletotrichum sp., Fusarium sp. e Rhizoctonia sp. Os resultados dos postulados de Koch indicaram que H. solani é o responsável pelos ataques de sarna prateada na região de Tulelake. Em campos de batata naturalmente infestados, observou-se que infecções de H. solani ocorreram em todos os três campos estudados, entretanto, a extensão das infestações diferiram significativamente entre os campos. Durante o armazenamento, a incidência da sarna prateada aumentou progressivamente em todos os armazéns. A percentagem da superfície do tubérculo afetada por sarna prateada aumentou de 3,5% para 35,5% durante o período de armazenamento. O número de lesões de H. solani por tubérculo também aumentou de 6 para 35 lesões por tubérculo após 6 meses de armazenamento. As populações de esporos de H. solani também aumentaram significativamente ao longo do período de armazenamento em todos os armazéns estudados. Entretanto, esses aumentos não foram contínuos, ou seja, as populações apresentaram múltiplos picos de aumento e redução durante o período de armazenamento.

A new potato tuber disease has been observed in the Tulelake region, California, USA, since 1995, with tuber symptoms suggestive of silver scurf disease (Helminthosporium solani). In this work we isolated, identified and demonstrated the nature of the causal agent of this potato disease in California. In addition, the distribution of H. solani in potato fields and the inoculum potential at harvest time were investigated. Disease progress and H. solani spore populations were also characterised under commercial storage conditions. The main fungal genera associated with potato tubers in storage were Helminthosporium solani, Colletotrichum sp., Fusarium sp., and Rhizoctonia sp. The results of Koch's postulates indicated that H. solani is responsible for the outbreak of silver scurf in the Tulelake region. In a disease survey in three commercial potato fields naturally infested, H. solani infections occurred in all fields. However, the extension of the infections differed significantly between the fields. During potato storage, silver scurf usually increased over time. The percentage of the tuber surface covered by silver scurf varied from 3.5% up to 35.5% during the storage period. The number of H. solani lesions per tuber also progressively increased from 6% up to 35%, six months after storage. H. solani spore populations also increased over time in all studied potato stores; nevertheless, they followed no consistent pattern, exhibiting multiple and variable peaks of increase and reduction during the period of storage.