Brevipalpus mites Donnadieu (Prostigmata: Tenuipalpidae) associated with ornamental plants in Distrito Federal, Brazil

Brevipalpus mites colonize a great number of fruit and ornamental plants. Mite species belonging to this genus have been associated with many plant viruses. Citrus leprosis (CiLV) is the most economically important virus transmitted by B. phoenicis mites. It has recently been shown that ornamental plant species can be alternative hosts of this virus. The high volume of trade and frequent movement of live ornamental plants make them efficient pest disseminators. Because of this, it is desirable to expand knowledge of potential pests aiming to guide the adoption of quarantine measures. This work reports ornamental plant hosts of Brevipalpus mites in the Distrito Federal (DF), as well the occurrence of symptoms consistent with Brevipalpus-borne plant viruses in these same hosts. Between July and September of 2005, five surveys were carried out in 14 localities within DF. Leaves and branches of fifty-five ornamental plant species were sampled. The species Pithecellobium avaremotemo Mart. is for the first time reported as a host for B. phoenicis (Geijskes), B. californicus Banks and B. obovatus Donnadieu species. Additionally, seven new species are reported as hosts for Brevipalpus within South America. New hosts are also listed for individual mite species. Typical symptoms of Brevipalpus-borne viruses were observed in Ligustrum sinense Lour., Pelargonium hortorum L.H. Bailey, Hibiscus rosa-sinensis L. and orchids (Dendrobium and Oncidium). The results of this work emphasize the potential role of the ornamental plants as vehicles for dissemination of Brevipalpus mites.

Os ácaros do gênero Brevipalpus colonizam um grande número de espécies frutíferas e ornamentais e têm sido associados a viroses de muitas plantas. A leprose dos citros é a virose de maior importância econômica transmitida por esses ácaros. Recentemente foi comprovado que algumas plantas ornamentais podem ser hospedeiras alternativas desse vírus. Os grandes volumes e a alta movimentação das plantas ornamentais fazem com que estas ajam como eficientes disseminadoras de pragas. Por essa razão, é necessário ampliar o conhecimento sobre pragas potenciais, de modo a subsidiar a implementação de medidas quarentenárias. Neste trabalho são relatadas as plantas ornamentais hospedeiras de ácaros Brevipalpus no Distrito Federal, assim como a ocorrência de sintomas típicos de viroses a elas transmitidas por Brevipalpus. Entre julho e setembro de 2005, foram realizadas cinco coletas em 14 localidades do DF. Foram amostradas folhas e ramos de 55 espécies de ornamentais. Pithecellobium avaremotemo Mart. é relatada, pela primeira vez, como hospedeira das espécies B. phoenicis (Geijskes), B. californicus Banks e B. obovatus Donnadieu. Adicionalmente, são relatadas sete novas espécies como hospedeiras de Brevipalpus na América do Sul. Novos hospedeiros são também listados para cada uma das espécies. Sintomas típicos de viroses transmitidas por Brevipalpus foram observados em Ligustrum sinense Lour., Pelargonium hortorum L.H. Bailey, Hibiscus rosa-sinensis L. e orquídeas (Dendrobium e Oncidium). Os resultados deste trabalho enfatizam o papel potencial de plantas ornamentais como veículo para disseminação de ácaros Brevipalpus.

Effect of Two Allexivirus Isolates on Garlic Yield.

Garlic (Allium sativum) is infected by numerous viruses forming a viral-complex, which is widely distributed in the garlic production regions of Argentina. This work is the first report of the effect of two Allexivirus isolates, Garlic virus A (GarV-A) and Garlic virus C (GarV-C), on garlic yield. Garlic cvs. Morado-INTA and Blanco-IFFIVE were used in the experiments, and four treatments were evaluated: plants inoculated with GarV-A only, GarV-C only, virus-free plants (negative control), and plants infected with the virus-complex. Assays were performed in anti-aphid cages and in the field during 2002 and 2003. GarV-A caused significant reductions in bulb weight (14 to 32%) and diameter (6 to 11%) compared with the negative control in the two cultivars under both assay conditions. GarV-C caused less damage than GarV-A (15% in weight and 5% in diameter) with respect to the negative control in cv. Blanco-IFFIVE, and did not produce significant yield losses in cv. Morado-INTA in either year or under either assay condition.