Chemical treatment of papaya seeds aiming at long-term storage and control of damping off

Damping off is a nursery disease of great economic importance in papaya and seed treatment may be an effective measure to control. The aim of this work was to evaluate the quality of papaya seeds treated with fungicides and stored under two environmental and packaging conditions. Additionally, the efficiency of fungicide treatments in the control of damping-off caused by Rhizoctonia solani was evaluated. Papaya seeds were treated with the fungicides Captan, Tolylfluanid and the mixture Tolylfluanid + Captan (all commercial wettable powder formulations). Seeds of the control group were not treated. The seeds were stored for nine months in two conditions: packed in aluminum coated paper and kept at 7 ± 1ºC and in permeable kraft paper and kept in non-controlled environment. At the beginning of the storage and every three months the seed quality (germination and vigor tests), emergence rate index, height, dry mass and damping of plants in pre and post-emergence (in contaminated substrate and mycelia-free substrate) were analyzed. Both storage conditions as well as the fungicide treatments preserved the germination and seed vigor. In the infested substrate, seedling emergence was favored by fungicides, but in post-emergence, fungicides alone did not control the damping off caused by R. solani. Symptoms of damping off were not observed in the clean substrate. The results showed that the fungicide treatments may be used to pretreat papaya seed for long-term storage and commercialization.

Silicon in plant disease control

All essential nutrients can affect the incidence and severity of plant diseases. Although silicon (Si) is not considered as an essential nutrient for plants, it stands out for its potential to decrease disease intensity in many crops. The mechanism of Si action in plant resistance is still unclear. Si deposition in plant cell walls raised the hypothesis of a possible physical barrier to pathogen penetration. However, the increased activity of phenolic compounds, polyphenol oxidases and peroxidases in plants treated with Si demonstrates the involvement of this element in the induction of plant defense responses. The studies examined in this review address the role of Si in disease control and the possible mechanisms involved in the mode of Si action in disease resistance in plants.

Postharvest biological control of brown rot in peaches after cold storage preceded by preharvest chemical control 1

ABSTRACT Pathogenic fungi cause skin darkening and peach quality depreciation in post harvest. Therefore, alternative techniques to chemical treatment are necessary in order to reduce risks to human health. The aim of this study was to evaluate the effect of the application of Trichoderma harzianum in association with different fungicides applied before harvest to 'Eldorado' peaches for brown rot control and other quality parameters during storage. The treatments consisted of five preharvest fungicide applications (control, captan, iprodione, iminoctadine and tebuconazole) associated with postharvest application of T. harzianum, after cold storage (with and without application), in three evaluation times (zero, two and four days at 20 °C), resulting in a 5x2x3 factorial design. The application of T. harzianum only brought benefits to the control of brown rot when combined with the fungicide captan, at zero day shelf life. After two days, there was a greater skin darkening in peaches treated with T. harzianum compared with peaches without the treatment, except for peaches treated with the fungicide iprodione and T. harzianum The application of T. harzianum during postharvest showed no benefits for the control of brown rot, however, the association with fungicides reduced the incidence of Rhizopus stolonifer during the shelf life.

Quantificação e precificação de risco de crédito através do modelo de opções

O trabalho está dividido em duas partes. Na primeira, são desenvolvidos os conceitos fundamentais para o entendimento do modelo de Black e Scholes com exemplos de sua utilização. Na segunda, inicialmente discute­se o conceito de risco das empresas. A seguir, através de uma aplicação, demonstra-se como uma empresa pode alterar favoravelmente o equilíbrio de risco e retorno: aceitando mais risco, aumentando seu débito ou pagando dividendos extras para os acionistas. Finalmente, mostra-se como os credores podem defender-se dessas mano­bras alterando adequadamente a taxa de juros, de forma a compensar o maior risco assumido e, assim, manter a posição de equilíbrio inicial entre risco e retorno.

Compra compulsiva e a influência do cartão de crédito

Este artigo investiga a influência do cartão de crédito sobre o comportamento de compra compulsiva entre jovens. A compra compulsiva é um estado de descontrole que visa a minimizar sentimentos negativos. Nesse contexto, o cartão de crédito pode ser um elemento impulsionador de compras que podem ter como possíveis conseqüências a geração de dívidas e problemas de relacionamentos. O estudo analisou tal comportamento entre jovens universitários, a partir de uma pesquisa de campo. Os resultados sugerem que, na amostra, os jovens com propensão à compulsividade usam o cartão de crédito de forma mais intensa. Sugere-se que as organizações envolvidas não negligenciem a questão da compra compulsiva e que suas responsabilidades sejam discutidas.

CESSÃO DE CRÉDITO E RESTRIÇÃO DE CAPITAL: UM ESTUDO COM BANCOS BRASILEIROS

Este estudo investiga a relação entre restrição de capital e as operações de cessão de crédito realizadas pelos bancos brasileiros. O período de análise, compreendido entre junho de 2004 e junho de 2009 - em que as cessões de crédito aumentaram em quase 20 vezes, ante um crescimento de 162% no volume de crédito - inclui a crise financeira de 2008/2009, choque exógeno ao sistema financeiro brasileiro, durante o qual instituições financeiras enfrentaram dificuldades por causa da diminuição na captação por meio de depósitos livres e interbancários. Isso permite, também, verificar se os efeitos da restrição de capital sobre a cessão se exacerbam diante de crises financeiras. Os resultados observados indicam que um aumento na restrição de capital - próprio e de terceiros - está relacionado à expansão das operações de cessão de crédito realizadas pelos bancos brasileiros.