The Dominance of Fusarium meridionale Over F. graminearum Causing Gibberella Ear Rot in Brazil May Be Due to Increased Aggressiveness and Competitiveness.

In Brazil, Gibberella ear rot (GER) of maize is caused mainly by Fusarium meridionale, whereas F. graminearum is a minor contributor. To test the hypothesis that F. meridionale is more aggressive than F. graminearum on maize, six experiments were conducted in the south (summer) and one in the central-south (winter), totaling seven conditions (year × location × hybrid). Treatments consisted of F. graminearum or F. meridionale (two isolates of each) inoculated once 4 days after silk, inoculated sequentially and alternately (F. graminearum → F. meridionale or F. meridionale → F. graminearum) 6 days apart, or (in the central-south) inoculated sequentially without alternating species (F. meridionale → F. meridionale or F. graminearum → F. graminearum). Overall, severity was two times greater in the south (37.0%), where summer temperatures were warmer (20 to 25°C) than in central-south. In the south, severity was greatest in F. meridionale treatments (67.8%); followed by F. meridionale → F. graminearum (41.1%), then F. graminearum → F. meridionale (19.4%), and lowest in F. graminearum (2.1%), suggesting an antagonistic relationship. In the central-south (15 to 20°C), severity was generally higher in the sequential nonalternating inoculation treatments (F. meridionale → F. meridionale or F. graminearum → F. graminearum) than when either species was inoculated only once. Only nivalenol (NIV) or deoxynivalenol was detected when F. meridionale or F. graminearum, respectively, was inoculated singly, or sequentially with no alternation. Both toxins were found in grains harvested from the F. meridionale → F. graminearum treatment, whereas only NIV was found in kernels from the F. graminearum → F. meridionale treatment, suggesting that F. meridionale was more competitive than F. graminearum in coinoculations. The dominance of F. meridionale as a cause of GER in Brazil may be due in part to its higher aggressiveness and competitiveness compared with F. graminearum.

Claviceps purpurea e Bipolaris sp. como causa de ergotismo em bovinos no estado de Santa Catarina / Claviceps purpurea e Bipolaris sp. as a cause of ergotism in cattle in Santa Catarina State

Claviceps purpurea é o fungo associado ao ergotismo. Esta é uma enfermidade causada pela ingestão de escleródios chamados de ergot, que contém alcalóides que atuam em receptores adrenérgicos, dopaminérgicos e seratoninérgicos causando efeito direto em vasos sanguíneos, musculatura lisa e sistema nervoso central e autônomo. Descrevem-se dados epidemiológicos, sinais clínicos e lesões de uma enfermidade de bovinos caracterizada por hipertermia, taquicardia, taquipneia e ulcerações na coroa do casco de bovinos. Entre 2000 e 2014 foram diagnosticados 13 surtos, três da forma distérmica, sete da forma gangrenosa e três da forma convulsiva. Porém, em cinco destes sete surtos, nos locais onde esses animais pastoreavam havia alta incidência de inflorescências de Sporobolus indicus conhecido como "capim-mourão", infectadas por um fungo com coloração enegrecida, identificado como Bipolaris sp. A enfermidade foi reproduzida experimentalmente em cinco bovinos com a administração destas inflorescências. Os bovinos em experimentação receberam inflorescências de S. indicus respectivamente nas doses diárias de 0,1g/kg, 0,2g/kg, 0,2g/kg, 0,26g/kg e 0,34g/kg por um período de 4, 7, 9 e 30 dias. Após três a sete dias de ingestão das inflorescências infectadas, quatro dos cinco bovinos apresentaram diarreia e manifestaram taquicardia, taquipneia e hipertermia em algum período durante a ingestão. Estes sinais coincidiram com os dias mais quentes deste período. Um bovino manifestou hiperemia na coroa do casco e perda de pêlos da extremidade da cauda. Baseado na reprodução experimental é possível afirmar que o capim Sporobolus indicus infectado pelo fungo Bipolaris sp é capaz de causar diarreia, hipertermia, taquicardia, taquipneia, hiperemia na coroa do casco e perda de pêlos da extremidade da cauda.(AU)

Claviceps purpurea is the fungus associated with ergotism. Ergotism is a disease caused by the ingestion of esclerodios called ergot, which contains alkaloids that act on dopaminergic and adrenergic receptors, causing seratoninergic effect on blood vessels, smooth muscles and central nervous and autonomic system. The present study describes epidemiological data, clinical signs and lesions of a bovine cattle disease characterized by hyperthermia, tachycardia, tachypnea and injuries in the coronary band of the hooves. Initially the cause was attributed to the fungus Claviceps purpurea. Between 2000 and 2014, 13 outbreaks were described, being three of distermic form, seven of gangrenous and three of the convulsive form. However, in five out of the seven of the gangrenous form outbreaks, it has been observed a high incidence of smut grass (Sporobolus indicus) inflorescences infected by a blackened fungus, classified as Bipolaris sp., in the places where the bovine grazed. The disease was reproduced experimentally by administration of inflorescences of smut grass contaminated by Bipolaris sp. Five bovine received daily doses of 0.1g/kg, 0.2g/kg, 0.2g/kg, 0.26g/kg and 0.34g/kg during 4, 7, 9, 30 and 30 days respectively. After three to seven days of eating contaminated inflorescences four cattle had diarrhea, tachycardia, tachypnea and intermittent hyperthermia. These clinical signs happened on the warmest days and during the warmest temperatures of the day. A bovine showed hyperemia in the coronary band of the hoof and loss of tail tip hair. According to data obtained during the experimental reproduction, smut grass contaminated by Bipolaris sp. can cause hyperthermia, tachycardia, tachypnea, injuries in the coronary band of the hoof and loss of the tail tip hair in bovine cattle.(AU)