Ear rots caused by Fusarium spp. are among the main fungal diseases that contribute to poor quality and the contamination of maize grains with mycotoxins. This study aimed to determine the visual incidence of fungal-damaged kernels (FDKs), the incidence of two main Gibberella (a teleomorph of Fusarium) complexes (G. fujikuroi and G. zeae) associated with maize using a seed health blotter test, and the fumonisin levels, using high performance liquid chromatography, in samples of maize grains grown across 23 municipalities during the 2008/09 and 2009/10 growing seasons. Additionally, 104 strains that were representative of all of the analysed samples were identified to species using PCR assays. The mean FDK was seven per cent, and only six of the samples had levels greater than six per cent. Fusarium spp. of the G. fujikuroi complex were present in 96% of the samples, and G. zeae was present in 18% of the samples (5/27). The mean incidence of G. fujikuroi was 58%, and the incidence of G. zeae varied from 2 to 6%. FB1 was found in 58.6%, FB2 in 37.9%, and both toxins in 37.9% of the samples. The FB1 and FB2 levels were below the quantification limits for 41.3% of the samples, and the mean FB1 levels (0.66 µg/g) were higher than the mean FB2 levels (0.42 µg/g). The PCR identification separated the 104 isolates into three of the G. fujikuroi complex: F. verticillioides (76%), F. subglutinans (4%) and F. proliferatum (2%); and G. zeae (anamorph = F. graminearum) (18%). Our results confirmed the dominance of F. verticillioides, similar to other regions of Brazil, but they differed due to the relatively higher incidence of F. graminearum. Total fumonisin levels were below the maximum limit determined by current Brazilian regulations.

Didymella bryoniae, agente causal da podridão gomosa, é um importante patógeno em meloeiro nobre, em cultivo protegido e recentemente, resultados de alguns trabalhos têm evidenciado a ocorrência de infecção latente de D. bryoniae em meloeiro, sem, no entanto, registrar a comprovação. Objetivou-se com este trabalho constatar a ocorrência de infecção latente de D. bryoniae, em plantas dos híbridos de meloeiro nobre Sunrise, Bônus II e Prince Hakucho assintomáticas. Empregou-se a técnica de reação da polimerase em cadeia (PCR), com o conjunto de 'primers' D7S, D6 e UNLO28822, que amplificam regiões do DNA e distinguem D. bryoniae de outras espécies similares e de outros microrganismos comuns. Em todos os híbridos testados, constatou-se a presença de D. bryoniae no caule de plantas assintomáticas, através da amplificação das regiões específicas delimitadas pelos 'primers' utilizados.

The causal agent of gummy stem blight, Didymella bryoniae, is an important pathogen for Cucurbitaceae species and has been the main source of biotic and infectious damages to muskmelon under protected cultivation. Some recent studies have evidenced the occurrence of latent infections by D. bryoniae in melons, but without confirmation. Thus, the present study aimed to the occurrence of latent infection by Didymella bryoniae in asymptomatic plants of the muskmelon hybrids Sunrise, Bonus II and Prince Hakucho through polymerase chain reaction (PCR) using the set of primers D7S, D6 and UNLO28822, which amplify DNA regions capable of distinguishing D. bryoniae from other similar species and common microorganisms. In all tested hybrids, the presence of D. bryoniae was confirmed in the stems of asymptomatic plants through amplification of specific regions delimited by the employed primers.

Os objetivos deste trabalho foram analisar o efeito da temperatura e da luz na germinação in vitro de urediniósporos de Phakopsoraeuvitis, assim como avaliar a viabilidade dos urediniósporos armazenados em diferentes temperaturas. Para a determinação do período de incubação foi avaliada a germinação dos urediniósporos em ágar-água 2%, após 2, 4, 6, 8, 10, 12 e 24 h. Para avaliar o efeito da temperatura e da luz na germinação, placas de Petri contendo suspensão de urediniósporos foram mantidas no escuro e sob luz contínua, nas temperaturas de 15, 20, 25 e 30 ºC, por um período de 24 h. No estudo de viabilidade, urediniósporos armazenados em tubos Eppendorf foram mantidos nas temperaturas de -20±2, 5±2, 23±2 e 33±2ºC, no escuro. Verificou-se o aumento contínuo na germinação dos esporos entre as avaliações com 6 a 24 horas de incubação. As temperaturas cardinais (mínima, ótima e máxima) para a germinação de urediniósporos in vitro estimadas foram de 11,6; 21,0 e 30,6 ºC; e 13,1; 21,0 e 30,0 ºC; respectivamente, nas condições de luz contínua e escuro. A viabilidade dos esporos foi reduzida drasticamente no período de 60 dias de armazenamento, verificando-se maior preservação na temperatura de 23±2 ºC.

The objectives of this research were to analyze the effect of temperature and light on in vitro germination of Phakopsora euvitis urediniospores, as well as the viability of urediniospores stored under different temperatures. For determined the incubation period was evaluate the germination of urediniospores in water-agar 2%, for 2, 4, 6, 8, 10, 12 e 24 h. In order to evaluate the effect of temperature and light in germination, urediniospores in a suspension onto petri dishes were kept at 15, 20, 25 and 30 ºC for 24 h, in the dark and under continuous light. For the viability study, urediniospores were stored in Eppendorf tubes at temperatures of -20±2, 5±2, 23±2 and 33±2 ºC, in dark. Viability was assessed through the germination of urediniospores on agar-water. It was observed that germination increased continuously between 6 to 24 h of incubation. The cardinal temperatures (minimum, optimal and maximum) for urediniospore germination in vitro was 11,6; 21,0 e 30,6 ºC; e 13,1; 21,0 e 30,0 ºC; respectively, under continuous light and in dark. The spore viability was drastically decreased during the 60-day period of storage; and the best temperature for storage was 23±2 ºC.