ABSTRACT Some psyllids transmit 'Candidatus Liberibacter solanacearum' (Lso), the causal agent of devastating plant diseases of cultivated Solanaceae and Apiaceae. The recent detection of Bactericera cockerelli and Lso in Ecuador seriously threatens these crops in South America. There, neither the role of native psyllids in the Lso epidemiology nor the psyllid fauna of vegetables are known. With the aim to identify potential vectors and risk scenarios for the spread of Lso in South America, a survey of the psyllid fauna of Solanaceae and Apiaceae crops and associated weeds was conducted in Brazil. Samples were taken at 29 localities in four states. A total of 2857 specimens were sampled, representing at least 37 species of 23 genera and seven families. The most frequent species on carrot, chilli pepper and potato were Russelliana solanicola, R. capsici and Isogonoceraia divergipennis, respectively. Immatures of R. capsici were found on chilli pepper and of R. solanicola on carrot and potato, confirming these plants as hosts. The two psyllid species have been suspected previously to transmit plant pathogens of unknown identity. Russelliana solanicola is one of the few polyphagous species. Here the species is reported for the first time from carrot. Recent collections in Rio Grande do Sul suggest that Solanum laxum represents the original host of R. capsici, which subsequently shifted to chilli pepper. Both, adaptation to agricultural crops and the possibility of ability to transmit pathogens, make the two Russelliana species dangerous potential vectors of Lso and other plant pathogens in South America. Candidatus solanacearum Lso, , (Lso) America There known Brazil 2 states 285 sampled 3 families R divergipennis respectively hosts identity Both (Lso 28

Aphids are the most important vectors of viruses infecting potato (Solanum tuberosum). We focused on the response of the aphid vector Myzus persicae (Sulzer) to five commercial potatocultivars: Ágata, Jaette Bintje, Mondial, Monalisa and Santè, by traditional antibiosis and antixenosis tests and by the EPG (Electrical Penetration Graph) technique, as a step forward to the design of effective management practices. Our aim was to identify plant factors involved in resistance of these cultivars against M. persicae, both at the surface and in deeper plant tissues. Results from the antixenosis test confirmed a strong preference of M. persicae for the Mondial cultivar. The antibiosis study indicated a lower population development of the aphid in 'Monalisa' when compared to 'Ágata' and 'Jaette Bintje'. EPG assays indicated that 'Santè' inhibited the initial feeding process of M. persicae, whereas 'Monalisa' showed a physical-type of resistance as demonstrated by a very high number of short probes. The cultivar Mondial showed average values for all EPG variables analyzed. The behavior in 'Jaette Bintje' indicated this cultivar was an ideal host for aphid feeding and reproduction. Together, the EPG data revealed the existence of pre and post-phloematics factors in the cultivars under study, which have important implications on the efficiency of transmission and spread of virus in potato by M. persicae.

In some American countries, grapevines are affected by Pierce's 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.

A população de Hemiptera Auchenorrhyncha foi estudada em pomares de laranja doce (Citrus sinensis), cafezais (Coffea arabica) e floresta estacional semidecidual com fisionomia arbustiva, em Bebedouro (SP), com o objetivo de avaliar a influencia do ecossistema natural na composição de espécies do agroecossistemas. O monitoramento foi feito com cartões adesivos amarelos, os quais foram trocados a cada 15 dias, efetuando-se a contagem e identificação dos Auchenorrhyncha coletados. Capturou-se o total de sete famílias, 11 subfamílias e 98 espécies, sendo Cicadellidae o grupo mais abundante. A floresta nativa apresentou a maior riqueza, diversidade e equitabilidade de espécies de Auchenorrhyncha, demonstrando ser mais estável que os demais habitats. Os altos valores de similaridades obtidos entre os agroecossistemas e a floresta demonstram que grande parte das espécies de cigarrinhas que está ocorrendo nos habitats agrícolas também está ocorrendo na floresta, indicando que esta pode estar funcionando como reservatório de espécies. A abundância de grupos taxonômicos de Auchenorrhyncha coletados variou nos habitats avaliados, sendo Proconiini o mais abundante no cafezal próximo à floresta, Athysanini, Scaphytopiini, Neocoelidiinae e Coelidiinae no pomar de laranja e cafezal distante da floresta; Cicadellinae e Agalliinae não se relacionaram a nenhum dos habitats. A presença de insetos vetores e possíveis vetores de doenças de plantas cultivadas nos habitats avaliados indicam a necessidade da implantação do manejo de pragas nessa área.

The population of Hemiptera Auchenorrhyncha was studied in sweet citrus groves (Citrus sinensis), coffee plantations (Coffea arabica) and a semi-deciduous seasonal forest with shrub physiognomy in Bebedouro, SP, to evaluate the influence of the natural ecosystem on the species composition of the agroecosystems. Monitoring was carried out by using yellow stick cards, which were replaced every 15 days and all Auchenorrhyncha collected were counted and identified. Seven families, 11 subfamilies and 98 species were collected, with Cicadellidae being the most abundant. The native forest presented larger wealth, diversity and equitability of Auchenorrhyncha species, demonstrating to be more stable than the other habitats. The high values of similarities obtained between the agroecosystems and the forest demonstrated that great part of Auchenorrhyncha species occurring in the agricultural habitats was also occurring at the forest, indicating that the last may serve as reservoir of species. The abundance of the taxonomic groups of Auchenorrhyncha collected varied with the evaluated habitats, with Proconiini being the most abundant in the coffee plantation next to the forest, Athysanini, Scaphytopiini, Neocoelidiinae and Coelidiinae in the orange orchard and coffee plantation distant from the forest; Cicadellinae and Agalliinae were not related to any of the habitats. The presence of vector insects and possible vectors of plant diseases in the appraised habitats indicate the need of the implementation of strategies for landscape management.

O agente causal da clorose variegada dos citros, Xylella fastidiosa, é transmitido por cigarrinhas da subfamília Cicadellinae, cujas espécies variam regionalmente. O objetivo deste trabalho foi identificar potenciais vetores do patógeno em pomares cítricos do Litoral Norte da Bahia. Os levantamentos foram conduzidos de mar/2002 a fev/2003, em três propriedades no município de Rio Real, em pomares de laranjeira doce (Citrus sinensis) variedade Pêra, com sete a nove anos. Em cada pomar, 15 cartões adesivos amarelos foram dispostos a 40 m entre si, instalados a 1,5 m de altura em ramos da face norte, na periferia da copa, sendo substituídos quinzenalmente. Também foram realizadas amostragens com rede de varredura na vegetação rasteira dos pomares, em cinco pontos escolhidos aleatoriamente, efetuando-se 30 redadas por ponto. No total, foram coletados 1360 espécimes pertencentes a 49 espécies de Auchenorrhyncha, a maioria da família Cicadellidae (90,2%). A subfamília Cicadellinae, que inclui os vetores de X. fastidiosa, apresentou maior número de espécies (14) e de indivíduos coletados (84,8%). Entre as espécies de Cicadellinae, Acrogonia flagellata Young, A citrina Marucci & Cavichioli, Homalodisca spottii Takiya, Cavichioli & McKamey e uma espécie não-identificada de Cicadellini (espécie 1) foram dominantes na copa das plantas cítricas, enquanto que Hortensia similis (Walker) e Erythrogonia dubia (Medler) foram dominantes na vegetação rasteira. Entre os cicadelíneos já conhecidos como vetores de X. fastidiosa em citros, apenas A. citrina, Bucephalogonia xanthophis (Berg) e Ferrariana trivittata (Signoret) foram observados, sendo que as duas últimas espécies tiveram ocorrência acidental na vegetação rasteira.

The causal agent of citrus variegated clorosis, Xylella fastidiosa, is transmitted by leafhoppers of the subfamily Cicadellinae, whose species vary regionally. The goal of this study was to identify potential vectors of this pathogen in citrus groves of Bahia North Coast, Brazil. The survey was done from March/2002 to February/2003 in three seven- to nine-year-old sweet orange (Citrus sinensis, Pêra variety) groves located in Rio Real, BA. Fifteen yellow sticky cards (8.5x11.5 cm) were installed 40 m apart in each grove, hanged at 1.5 m high on the upper north side of citrus canopies, and replaced fortnightly. A sweep net was periodically used to sample leafhoppers on herbaceous weeds inside the groves, by selecting five points at random and performing 30 sweeps in each point. A total of 1,360 specimens of 49 Auchenorrhyncha species were collected in this study, mostly in the family Cicadellidae (90.2%). The subfamily Cicadellinae, which includes the sharpshooter vectors of X. fastidiosa, showed the largest number of species (14) and specimens (84.8%). Acrogonia flagellata Young, A. citrina Marucci & Cavichioli, Homalodisca spottii Takiya, Cavichioli & McKamey and an unidentified Cicadellini (species 1) were the dominant species trapped on citrus canopies, while Hortensia similis (Walker) and Erythrogonia dubia (Medler) were dominant in the weedy vegetation. Among the Cicadellinae species already known as vectors of X. fastidiosa in citrus, only A. citrina, Bucephalogonia xanthophis (Berg) e Ferrariana trivittata (Signoret) were found. The two latter species were accidentally trapped by sweep net in the weedy vegetation.