Areolate mildew, caused by Ramularia areola is an important disease affecting cotton in Brazil. A few years ago this disease was of secondary importance since it used to occur almost at the end of the crop cycle. However, in recent years the disease has gained considerable importance in the main cotton growing areas of Brazil. Amongst control alternatives is the use of fungicides and resistant cultivars the latter being preferred. In order to study the inheritance of cotton resistance to R. areola, plant populations derived from the crossing between the resistant line FMT02102996 and the susceptible cultivar Novaes, T.G.; Almeida, W.P.; Schuster, I.; Aguiar, P.; Mehta, Y.R.. Inheritance of cotton resistance to Ramularia areola. Summa Phytopathologica, v.37, n.2, p.150-152, 2011.Keywords: Gossypium hirsutum, genetics, inheritance of resistance.Palavras-chave adicionais: Mancha-de-ramularia, Gossypium hirsutum, genética. RESUMOA mancha-de-ramularia, doença causada pelo fungo Ramularia areola, é uma das doenças de destaque na cotonicultura brasileira. Há alguns anos atrás, esta doença era considerada de final de ciclo da cultura, mas em anos recentes tornou-se a doença de maior importância econômica nas principais regiões produtoras de algodão do Brasil. Dentre as alternativas de controle, estão o uso de fungicidas e o uso de cultivares resistentes, sendo que o último é o preferido. Visando estudar a herança da resistência do algodoeiro a R. areola, foram avaliadas populações derivadas do cruzamento entre a linhagem FMT02102996, como resistente e a cultivar FMT 701, como suscetível. As plantas Novaes, T.G.; Almeida, W.P.; Schuster, I.; Aguiar, P.; Mehta, Y.R.. Herança de resistência do algodoeiro a Ramularia areola. Summa Phytopathologica, v.37, n.2, p.150-152, 2011.FMT 701, were evaluated. These plants were classified as resistant or susceptible by means of artificial inoculation in greenhouse. The segregation test was done through ÷2 test. Results indicated that cotton resistance to areolate mildew is controlled by a dominant gene. This finding can assist in planning cotton breeding programs aimed at incorporating resistance to R. areola in nem cultivars, constituting basic information for the beginning of the genetic mapping of this resistance gene in agronomically desirable cotton cultivars.foram classificadas como resistentes ou suscetíveis por meio de inoculação artificial em casa de vegetação. Realizou-se teste de segregação por meio de teste qui-quadrado. Os resultados obtidos indicam que a resistência do algodoeiro à mancha-de-ramularia é condicionada por um gene dominante. Este resultado pode auxiliar o planejamento dos programas de melhoramento do algodoeiro na incorporação da resistência a R. areola em novas cultivares, também consti tuin do informaç ão bási ca p ara o i níci o de trabalhos de mapeamento genético deste gene de resistência agronomicamente desejável.A mancha-de-ramularia, doença causada pelo fungo Ramularia areola, é uma das doenças de destaque na cotonicultura brasileira. Também ...

Earlier studies showed that the resistance of cotton genotype FMT 02102996 to Ramularia areola is governed by one dominant gene. More recently, the resistance of another genotype CNPA BA 2003-2059 to R. areola was detected under field and glasshouse conditions. Present investigation was conducted to verify the mechanism of resistance of the genotype CNPA BA 2003-2059 and to find out if the resistance of these two genotypes is governed by the same or by different genes. Segregating plant populations derived from the cross between the resistant genotype CNPA BA 2003-2059 and the susceptible genotype FMT 701, the back cross populations, as well as those derived from the cross between the two resistant genotypes were evaluated for disease severity by artificial inoculations under glasshouse conditions. The ratio of plants segregating for resistance and susceptibility was studied by χ2 test. The results indicated that the resistance to R. areola in genotype CNPA BA 2003-2059 is governed by one dominant gene and that the resistance in each one of the resistant genotypes is governed by a different dominant gene. These results may assist the local breeding programs aimed at pyramiding resistance genes to this pathogen and may form the basis for genetic mapping of resistance genes. Key words: Gossypium hirsutum, genetics, inheritance of resistance. RESUMO Mecanismo de resistência e presença de genes diferentes de resistência a Ramularia areola em dois genótipos de algodoeiroA mancha-de-ramulária, causada por Ramularia areola, é uma das doenças de importância econômica para o Brasil. Estudos anteriores demonstraram que a herança da resistência do genótipo FMT 02102996 a R. areola é governada por um gene dominante. Recentemente, a resistência do genótipo CNPA BA 2003-2059 a este patógeno foi verificada em casa de vegetação e no campo. O presente estudo foi realizado para verificar o mecanismo de resistência deste genótipo e verificar se os genes de resistência dos dois genótipos resistentes são os mesmos. Foram avaliadas populações segregantes derivadas do cruzamento entre o genótipo resistente CNPA BA 2003-2059 e o genótipo suscetível FMT 701, dos retrocruzamentos, e também do cruzamento entre os dois genótipos resistentes. As plantas foram classificadas como resistentes ou suscetíveis por meio de inoculação artificial. Com base nos resultados, constatou-se que a resistência do genótipo CNPA BA 2003-2059 é condicionada por um gene dominante e que os dois genótipos possuem um gene diferente de resistência. Estes resultados podem auxiliar o planejamento dos programas de melhoramento do algodoeiro visando piramidar genes de resistência a R. areola em novas cultivares, ao mesmo tempo constituindo informação básica para o início de trabalhos de mapeamento genético deste gene de resistência. Palavras-chave: Gossypium hirsutum, genética, herança de resistência.

A virus was isolated from soybean (Glycine max) plants with symptoms of dwarfing and bud blight in Wenceslau Braz County, Paraná, Brazil. The host range and properties resembled those of Tobacco streak virus (TSV). The purified virus showed three peaks in a frozen sucrose gradient. Antiserum was produced and the virus was serologically related to TSV. Electron microscopy detected 28 nm spherical particles. Coat protein (CP) had a Mr of 29.880 Da. A fragment of 1028 nt was amplified, cloned and sequenced. One open reading frame with 717 nt was identified and associated to the CP. The CP gene shared 83% identity with the sequence of TSV CP from white clover (Trifolium repens) (GenBank CAA25133). This is the first report of the biological and molecular characterization of TSV isolated from soybeans. It is proposed that this isolate be considered a strain of TSV named TSV-BR.

-Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis are commonly found in avocado and persimmon orchards in northern Parana state. However, their abundance depends on whether insecticides are used or not to control the key lepidopteran pests Stenoma catenifer (Wals.) (Lepidoptera: Elachistidae) and Hypocala andremona (Stoll) (Lepidoptera: Noctuidae), respectively. The aim of this work was to evaluate the effects of an aqueous neem seed extract (ANSE) at 15, 3 and 1.5%, and of an emulsifi able concentrate neem oil (ECNO) at 2.5, 0.5 and 0.25% on lifetime parameters of these trichogrammatids as a way of testing the feasibility of integrating the biological and chemical control methods. Chemicals were applied on Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs before or after parasitization (one, three or fi ve days). ANSE was more deleterious to both parasitoid species than ECNO, regardless of the concentration and the time of application. The chemicals acted on a concentration and time dependent manner. Treating the host with neem before parasitism was less deleterious to wasp emergence, especially for T. annulata. Pre-treatments (24h) of the host eggs with ECNO at concentrations varying from 0.5% to 0.25% did not affect T. pretiosum longevity, but 2.5% reduced T. annulata survival. Feeding wasps with honey mixed with 0.25% ECNO negatively affected T. annulata survival.

The avocado fruit borer, Stenoma catenifer (Wals.) has been a limiting factor in growing avocados over the last years in many Brazilian states. This is a result of the lack of safe and feasible management practices to minimize the fruit borer damage. The aim of this study was to obtain information on the pest biology and ecology as well as on the role of natural enemies to define strategies to control the pest. Samples were taken biweekly and consisted of 20 fruits collected randomly (10 from the upper half and 10 from the lower half of the plant) in ten plants, cv. Margarida, in a commercial avocado grove in Arapongas and Cambé regions, PR, from October/2001 to September/2002. Laboratory determinations of the percentage of damaged fruit per plant region, location and number of bored fruit sites, and the number and location of the fruit borer eggs, including parasitized ones, were performed. The results showed that S. catenifer preferred to oviposit and attack fruits located on the upper half of the trees. The majority of the eggs were laid on the fruit pedicel whereas the damage was mainly located on the lower half of the fruits. Trichogrammatids were the most constant and abundant parasitoids found in both localities throughout the study period.