RESUMO A pimenta-de-cheiro, Capsicum chinense é uma cultura importante na Bacia Amazônica, cultivada principalmente por pequenos produtores. Plantas de C. chinense em um campo experimental localizado no norte do estado brasileiro do Amazonas, foram encontradas apresentando sintomas característicos de infecção viral. Extratos de amostras de folhas sintomáticas examinados ao microscópio eletrônico de transmissão revelaram a presença de partículas alongadas e flexuosas e de partículas isométricas. Análises moleculares permitiram identificar a presença do pepper yellow mosaic virus (PepYMV) e do cucumber mosaic virus (CMV). Pulgões, identificados como Aphis gossypii foram encontrados colonizando pimenteiras-de-cheiro neste campo experimental e podem representar o provável vetor de PepYMV e CMV. Este trabalho relata a primeira ocorrência desses vírus infectando C. chinense no estado do Amazonas.

ABSTRACT The habanero chilli pepper, Capsicum chinense is an important crop in the Amazon Basin, mainly grown by small-scale producers. Capsicum chinense plants in an experimental field in the northern Brazilian state of Amazonas were found exhibiting characteristic symptoms of viral infection. Leaf sap from symptomatic plants examined under a transmission electron microscope revealed the presence of elongated flexuous particles and isometric particles. Using molecular assays, the viruses were identified as pepper yellow mosaic virus (PepYMV) and cucumber mosaic virus (CMV). Aphids, identified as Aphis gossypii, were found colonizing the C. chinense plants in the field and may be the vector for both PepYMV and CMV. We report the first occurrence of these viruses infecting C. chinense in the state of Amazonas.

Em um plantio comercial localizado no Vale do Ribeira, no estado de São Paulo, foram observadas plantas de abobrinha-de-moita (Cucurbita pepo L.) apresentando superbrotamento de ramos, malformação da parte aérea e folhas disformes e enrugadas. Através de PCR foi demonstrada a presença de fitoplasma associado aos tecidos doentes. Um fitoplasma do grupo 16SrIII foi identificado por PCR e pela análise de RFLP, conduzida com cinco enzimas de restrição. A presente comunicação se constitui no primeiro relato da presença de um fitoplasma do grupo 16SrIII em abobrinha-de-moita no Brasil.

In a commercial field located in the Vale do Ribeira, in the State of São Paulo, Brazil, plants of summer squash (Cucurbita pepo L.) exhibiting witches' broom and leaf deformation were observed. PCR assays demonstrated the presence of phytoplasma associated with diseased tissues. A phytoplasma belonging to the 16SrIII group was identified by PCR and RFLP analysis performed with five restriction enzymes. The present note is the first report of the presence of phytoplasma representative of the 16SrIII group in summer squash in Brazil.

Avaliou-se a transmissão de Passion fruit woodiness virus (PWV) por Aphis gossypii (Glover). Em dois experimentos independentes, o afídeo transmitiu o PWV para maracujazeiros com taxas de 75% e 100%, ao se depositarem oito e doze afídeos virulíferos por planta, respectivamente. No final dos testes, observaram-se, em algumas plantas de maracujá, formas ápteras e ninfas de A. gossypii, sugerindo a colonização dessas plantas pelo afídeo. Esse parece ser o primeiro relato da colonização de Passiflora edulis f. flavicarpa (Deneger) por uma espécie de afídeo.

The transmission of Passion fruit woodiness virus (PWV) by Aphis gossypii (Glover) was evaluated. In two independent experiments, A. gossypii transmitted PWV to passion fruit plants at the rates of 75% and 100%, when eight and twelve viruliferous aphids were deposited by plant, respectively. At the end of the tests, nymphs of A. gossypii were observed in some of the passion fruit plants, suggesting that the aphid species was colonizing the plants. This seems to be the first report of Passiflora edulis f. flavicarpa (Deneger) colonization by a species of aphid.

Em São Paulo, ocorrem quatro isolados do vírus que induz o mosaico das nervuras da videira (Vitis spp.), os quais são diferenciados pelos sintomas que provocam em algumas variedades. Para confirmar a identidade desse vírus e o relacionamento existente entre os quatro isolados, foram aplicados os testes DAS-ELISA e TAS-ELISA usando anti-soros comerciais contra o Grapevine fleckvirus (GFkV). As fontes de antígeno foram tecidos de floema de ramos dormentes e de folhas jovens da brotação de primavera de videiras sabidamente infetadas. As reações nos testes imuno-enzimáticos envolvendo os quatro isolados do vírus foram positivas para o anti-soro contra o GFkV. Os resultados foram também positivos para amostras de 66 plantas infetadas de 26 variedades de videira procedentes de 11 regiões vitícolas de São Paulo e de 24 plantas de 12 variedades provenientes dos estados de Minas Gerais, Paraná, Pernambuco, Rio Grande do Norte e Santa Catarina. Extratos de folhas novas e tenras apresentaram valores de absorbância mais consistentes do que extratos de ramos dormentes. Plantas não infetadas foram empregadas como controle negativo. Os resultados obtidos confirmaram que os quatro isolados virais possuem relacionamento sorológico com o GFkV, sugerindo que os mesmos pertencem ao complexo viral que causa o "grapevine fleck disease".

In the State of São Paulo, four different isolates of the virus that induces chlorotic translucent vein break in the minor veins of grapevines (Vitis spp.) were separated by their differential biological behaviour and tested for their relationship to Grapevine fleck virus (GFkV) by DAS-ELISA and TAS-ELISA with commercial antisera against GFkV. Young leaves from spring shoots and dormant cuttings were used for antigen extraction. All infected plants were previously indexed by graft-inoculation to 'Rupestris du Lot'. The four isolates gave positive reactions to the GFkV antiserum. Positive ELISA reactions were observed in 66 samples of 26 varieties, from 11 grape-growing areas from the State of São Paulo as well as 24 samples, of 12 varieties, from five other states of Brazil. Healthy plants consistently gave negative results. Young leaves were better sources of antigen than cortical scrapings of dormant cuttings. The results showed that the four isolates have a serological relationship with the GFkV, suggesting that they belong to the viral complex that induce grapevine fleck disease.

The first observations on the presence of Bemisia tabaci biotype B (=B. argentifolii) in Brazil were made in the beginning of the 1990s in the State of São Paulo. from then on, that whitefly has spread out to other States. In the summer of 1997/98, B. tabaci biotype B reached Guaíra-Miguelopólis, an area of the State of São Paulo not yet infested, with high populations of the insect, mainly in soybean, cotton and vegetable crops. In the the first week of February 1998, during a survey in an abandoned field of soybean, an epizootic of Aschersonia cf. goldiana was verified on that whitefly in the whole area, with total infection of nymphs in the lower surface of the leaves. At the same date, in two other soybean fields of the region, the incidence of this entomopathogen was low, but it increased in the following two weeks, reaching high control levels of the insect, which was similar to the previously observed field. This occurrence indicates A. cf. goldiana as a potential agent for biological control of B. tabaci biotype B.

Since 1991, when the whitefly Bemisia argentifolii Bellows & Perring was first described in São Paulo, it dispersed rapidly to all the regions of Brazil. Although the high incidence of geminivirus is correlated with high population of this whitefly, the transmission efficiency of this insect is unknown. To determine whether the B. argentifolii is a vector of BGMV, two experiments were carried out. After an aquisition period of 24 hours on infected beans plants cv. Carioca 80, adults of the whitefly were transferred to seedlings of some cultivars, giving a period of inoculation of 24 hours. In the 1st experiment, the percentage of symptomatic plants were: 25.0% for Carioca 80, 21.0% for Moruna 80, 21.0% for Aeté, 75.0% for Preto and 26.3% for Manteiga. In the 2nd experiment, the percentage of virus transmission were: 63.6% for IAC Carioca and 60.0% for BT-2. The results showed that B. argentifolii is a vector of BGMV and apparently there are no marked differences in efficiency of transmission between this specie and Bemisia tabaci (Genn.).