Prácticas culturales para el manejo de la Sigatoka negra en bananos y plátanos

Black sigatoka (Mycosphaerella fijiensis) control consists in the continuous use of fungicide sprays and cultural practices. Cultural control reduces inoculum sources of the pathogen and favorable environmental conditions for its development, as well as it increases the vigor of the plants. In order to manage the disease it is necessary to know its behavior through the time, its relationship with the weather and the crop management. The most important cultural practice to reduce the inoculum source is the removal of the whole affected leaves or only the diseased portions of the leaves. The removed tissue is placed over the ground and the use of urea is feasible to accelerate its decomposition. An alternative practice is the "mini-composting" that consists in forming small heaps with the dead leaves and harvested plants for its quick degradation, which allows to reduce the pathogen inoculum and to incorporate nutrients and organic matters into the soil. The early pruning of the tips of the Young leaves before they show symptoms of the disease and the quick elimination of harvested plants reduce the inoculum. Also, the agronomic management of the crop helps to reduce the favorable conditions and to increase the vigor of the plants: this management considers plantation density, drainage systems, irrigation methods, control of weeds, chemical-biological fertilization, and nematode control.

Aspectos sanitários do cultivo da alface americana, irrigada com águas recptoras de efluentes urbanos

Avaliou-se a influência da disposição de mangueiras gotejadoras nos canteiros e a injeção ou não de cloro na água de irrigação, nas condições sanitárias do solo e da alface americana irrigada (Lactuca sativa L.) com águas receptoras de efluentes urbanos. Foram realizadas análises microbiológicas de amostras de água do solo e da alface, no decorrer de todo o ciclo de cultivo. Objetivou-se determinar a possível existência de Salmonella spp. e de formas evolutivas de parasitos humanos e a quantidade de coliformes fecais, em pontos e épocas diferentes do experimento, impedindo assim o consumo da alface. Os resultados não indicaram a presença dos dois primeiros em nenhuma das amostras, mas sim de parasitos não humanos (nematóides) de vida livre no solo. em relação à quantidade de coliformes fecais (NMP ml-1), o valor encontrado na cultura atende às exigências da Secretaria de Vigilância Sanitária do Ministério da Saúde brasileiro, porém a presença dos nematóides em quantidades superiores ao permitido pela Organização Mundial de Saúde (OMS) inviabiliza o seu consumo.

First record of molluscs naturally infected with Angiostrongylus cantonensis (Chen, 1935) (Nematoda: Metastrongylidae) in Brazil

Seeking the identification of Angiostrongylus cantonensis as a potential etiological agent of three clinical cases of eosinophilic meningitis, mollusc specimens were collected in the state of Espírito Santo, Brazil. The snails were identified as Sarasinula marginata (45 specimens), Subulina octona (157), Achatina fulica (45) and Bradybaena similaris (23). Larvae obtained were submitted to polymerase chain reaction and restriction fragment length polymorphism diagnosis. Their genetic profile were corresponded to A. cantonensis. Rattus norvegicus experimentally infected with third-stage larvae, developed menigoencephalitis, and parasites became sexually mature in the lungs. Additionally, larvae obtained from A. fulica snails, from São Vicente, state of São Paulo, also showed genetic profiles of this nematode. This is the first record of Brazilian molluscs infected with this nematode species.