Rudiney Ringenberg

Análise faunística de cigarrinhas (Hemiptera: Cicadellidae) na cultura da videira no Rio Grande do Sul

In some American countries, grapevines are affected by Pierces disease (PD), which is caused by a particular strain of Xylella fastidiosa not yet reported in Brazil. In order to investigate the potential for PD spread in Brazil in case of pathogen introduction, we conducted a faunistic analysis of leafhoppers (Hemiptera: Cicadellidae) associated to vineyards in the State of Rio Grande do Sul, with emphasis in the subfamily Cicadellinae (sharpshooters), which includes the main potential vectors of X. fastidiosa. Leafhopper samplings were carried out fortnightly during two years (9/2004-9/2006) in four Vitis vinifera vineyards in the municipalities of Bento Gonçalves and Farroupilha (RS). Thirtyfour leafhopper and six spittlebug species were collected, but most (98.4%) of the 3,893 specimens trapped were leafhoppers, distributed in the subfamilies Cicadellinae (60.2%), Gyponinae (34.1%), Deltocephalinae (3.8%) and Coelidinae (0.3%). The sharpshooter specimens were divided in the tribes Cicadellini (68.5%; 12 species) and Proconiini (31.5%; 11 species). Based on the faunistic indices, five species of Cicadellini, Bucephalogonia xanthophis (Berg), Dilobopterus dispar (Germar), Macugonalia cavifrons Stal, Sibovia sagata (Signoret) and Spinagonalia rubrovittata Cavichioli, and three of Proconiini, Molomea consolida (Schöder), Oncometopia facialis (Signoret) and Oncometopia fusca Melichar were prevalent in the vineyards. The high diversity of native sharpshooters in Rio Grande do Sul indicates the existence of a high risk of PD spread if the pathogen is introduced in grapevines.

Survey of potential sharpshooter and spittlebug vectors of Xylella fastidiosa to grapevines at the São Francisco River Valley, Brazil

Survey of potential sharpshooter and spittlebug vectors of Xylella fastidiosa to grapevines at the Sao Francisco River Valley, Brazil. Pierces disease of grapevines, caused by Xylella fastidiosa, is a serious problem in some regions of North America, not yet reported in Brazil. In this study, a survey of potential sharpshooter (Hemiptera, Cicadellidae, Cicadellinae) and spittlebug (Hemiptera, Cercopidae) vectors of X. fastidiosa was conducted in vineyards at the Sao Francisco River Valley, a major grape growing region in Brazil. Four vineyards of Vitis vinifera L. were sampled fortnightly from June/2005 to June/2007, using yellow sticky cards, each placed at two different heights (45 cm aboveground and 45 cm above the crop canopy) in 10 sampling localities. A total of 4,095 specimens of sharpshooters were collected, nearly all from 3 Proconiini species, Homalodisca spottii Takiya, Cavichioli & McKamey, 2006 (96.8% of the specimens), Tapajosa fulvopunctata (Signoret, 1854) (3.1%), and Tretogonia cribrata Melichar, 1926 (1 specimen). Hortensia similis (Walker, 1851) (2 specimens) was the only Cicadellini species. Only 1 cercopid specimen, belonging to Aeneolamia colon (Germar, 1821), was trapped. Even though they are not considered potential Xylella vectors, 2 Gyponini leafhoppers were collected: Curtara samera DeLong & Freytag, 1972 (11 specimens) and Curtara inflata DeLong & Freytag, 1976 (1 specimen). Homalodisca spottii was observed feeding and mating on green branches of grapevines, in addition to egg masses. Because of its prevalence on the crop canopy, occurrence throughout the year (with peaks from February to August), and ability to colonize grapevines, H. spottii could be an important vector if a X. fastidiosa strain pathogenic to grapevines becomes introduced at the Sao Francisco River Valley.

Secondary metabolite contents in different parts of cassava plants infested by Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae)

The objective of this study was to identify and quantify the secondary metabolites in different parts of cassava plants infested and non-infested by Phenacoccus manihoti. Experiments were conducted in a greenhouse at Embrapa Soja, Londrina, Paraná, Brazil, with a completely randomized design involving a 3u2009×u20092u2009×u20092 factorial arrangement [i.e., three cassava cultivars (‘Baianinha,’ ‘Santa Helena,’ and ‘IAC-12’), two canopy strata (apical and basal), and two levels of P. manihoti infestation (infested and non-infested)]. Cassava cuttings were vertically positioned in 5-L plastic pots. To generate cassava plants infested with P. manihoti, leaves containing five mass-reared first-instar nymphs were collected and placed on shoot apices. After 48xa0h, samples were collected for a subsequent extraction of metabolites. Extract aliquots were analyzed by high-performance liquid chromatography to detect and quantify compounds. Extracts from the apical and basal leaves of ‘Baianinha,’ ‘Santa Helena,’ and ‘IAC 12’ cassava cultivars contained caffeic acid, p-coumaric acid, ferulic acid, rutin, and trace amounts of gallic acid. Caffeic acid was mainly detected in the basal leaf extracts for all evaluated cultivars. Additionally, ferulic acid levels were relatively high in the ‘Baianinha’ and ‘Santa Helena’ basal leaves. Furthermore, rutin concentrations were higher in apical leaves than in basal leaves for all three cultivars, regardless of whether the plants were infested by P. manihoti. The presence of P. manihoti induced the production of rutin in the apical leaves of ‘Baianinha’ plants.

Metamasius hemipterus L. as a pest of bananas cv. Terra

Metamasius spp. nao e citado como praga da bananeira. Entretanto, o manejo cultural adotado nos bananais pode interferir na ocorrencia desses insetos. Este trabalho foi realizado com o objetivo de registrar a ocorrencia de Metamasius hemipterus L.. em bananal orgânico cv. Terra e seus danos em uma area experimental e de producao no municipio dexa0 Presidente Tancredo Neves, Bahia. Relata-se a ocorrencia de M. hemipterus como praga da bananeira cv. Terra. Alerta-se para a necessidade de monitoramento do inseto principalmente em sistemas de producao orgânica.