Adaptabilidade de linhagens de Botrytis squamosa resistentes a fungicidas do grupo dos benzimidazois e dicarboximidas.

A adaptabilidade de linhagens resistentes a benomyl, iprodione, duplo-resistentes e sensíveis de Botrytis squamosa, causador da Queima das Pontas da cebola, foi estudada através do crescimento micelial, produção de conídios, patogenicidade e competição in vitro e in vivo. As linhagens de B. squamosa resistentes a benomyl podem ser tão adaptadas quanto as sensíveis, ao passo que as resistentes a iprodione apresentaram-se menos adaptadas. As resistências a benomyl e a benomyl + iprodione mostraram-se instáveis, visto que permaneceram inalteradas após cinco gerações de transferências monospóricas na ausência dos fungicidas. Isolados tanto sensíveis quanto resistentes aos fungicidas benomyl e iprodione se anastomosaram livremente, exceto o isolado Pd 64, resisten-te a benomyl. O número de núcleos/conídio em duas linhagens (uma sensível e a outra resistente a benomyl) foi determinado, não tendo sido constatadas diferenças; ambas apresentaram ate 20 núcleos/conídio

Organic and conventional tomato cropping systems.

Among several alternative agricultural systems have been developed, organic agriculture has deserved increasing interest from. The objective of this paper was comparing both organic (OS) and conventional (CS) tomato cropping systems for varieties Débora and Santa Clara, through an interdisciplinary study. The experiment was set up in a randomized blocks design with six replicates, in a dystrophic Ultisol plots measuring 25 ´ 17 m. Cropping procedures followed by either local conventional or organic growers practices recommendations. Fertilization in the OS was done with organic compost, single superphosphate, dolomitic limes (5L, 60 g, and 60 g per pit), and sprayed twice a week with biofertilizer. Fertilization in the CS was done with 200 g 4-14-8 (NPK) per pit and, after planting, 30 g N, 33 g K and 10.5 g P per pit; from 52 days after planting forth, plants were sprayed once a week with foliar fertilizer. In the CS, a blend of insecticides, fungicides and miticides was sprayed twice a week, after planting. In the OS, extracts of black pepper, garlic, and Eucalyptus; Bordeaux mixture, and biofertilizer, were applied twice a week to control diseases and pests. Tomato spotted wilt was the most important disease in the OS, resulting in smaller plant development, number of flower clusters and yield. In the CS, the disease was kept under control, and the population of thrips, the virus vector, occurred at lower levels than in the OS. Variety Santa Clara presented greater incidence of the viral disease, and for this reason had a poorer performance than 'Débora', especially in the OS. Occurrence of Liriomyza spp. was significantly smaller in the OS, possibly because of the greater frequency of Chrysoperla. The CS had smaller incidence of leaf spots caused by Septoria lycopersici and Xanthomonas vesicatoria. However, early blight and fruit rot caused by Alternaria solani occurred in larger numbers. No differences were observed with regard to the communities of fungi and bacteria in the phylloplane, and to the occurrence of weeds

Ensaio sobre o controle de "damping-off' do cafeeiro

Testes de 3 fungicidas-Vapam, PCNB e Cupravit - foram conduzidos em 2 tipos de substrato, visando controlar "damping-off" do cafeeiro. Os substratos se comportaram de maneira diferente quanto ao número de plantas sadias obtidas. Os fungicidas agiram de maneira diferente em diferentes substratos. No substrato A os fungicidas diferiram na sua ação protetora enquanto que no solo B, não. No resultado finai, alguns tratamentos se mostraram superiores que outros