Symptoms of coffee leaf scorch (CLS) appear on young flushes of field plants as large marginal and apical scorched areas on recently mature leaves. Affected leaves drop, shoot growth is stunted, and apical leaves are small and chlorotic. Symptoms may progress to shoot dieback. Only scorched leaves which could not be related to other known agents consistently contained bacteria and bacterial agglomerates when observed with light microscopy. Only plants with these symptoms were positive in enzyme-linked immunosorbent assay (ELISA) tests using antiserum to Xylella fastidiosa Wells et al. The bacterium Xylella fastidiosa Wells et al. was isolated in November 1995 from coffee (Coffea arabica) leaves with scorch symptoms on supplemented periwinkle wilt medium. Colonies were circular, dome-shaped, white, and 0.5 to 1.5 mm in diameter. Two of 10 young coffee seedlings stem-inoculated with a suspension of the isolated X. fastidiosa in January 1996 showed leaf scorch symptoms 3 to 5 months later, contained bacteria in xylem extracts, and reacted positively in ELISA using antiserum to the citrus variegated chlorosis (CVC) strain of X. fastidiosa. ELISA-positive bacteria were reisolated from this plant. None of the symptomless plants, including controls, revealed bacteria on microscopic examinations, ELISA, or isolation attempts. Antisera developed against cultured bacteria from both CLS and CVC plants reacted positively against plant extracts of both diseases in dot immunobinding assays (DIBA). The level of detection was about 5 × 105 bacteria ml-1 for both homologous and heterologous reactions. The polymerase chain reaction amplification products produced by CLS and CVC strains of X. fastidiosa were indistinguishable. Geographical distribution of these strains is not the same. CLS is widespread and usually occurs if coffee is adjacent to CVC-affected citrus. However, CVC does not always occur when citrus is grown adjacent to CLS-affected coffee. The bacteria are closely related, if not identical.

Caracterização Geoestatística da Distribuição Espacial de Cigarrinhas Vetores de Xylella fastidiosa em CitrusRESUMO -A distribuição espacial das espécies de cigarrinhas (Dilobopterus costalimai Young, Acrogonia sp. e Oncometopia facialis Signoret), vetoras da Xylella fastidiosa, agente causal da Clorose Variegada dos Citros, foi estudada com o uso da geoestatística. As avaliações foram feitas em um pomar comercial de laranja 'Pêra' (Citrus sinensis [L.] Osb.), objetivando estabelecer meios para melhor controle dos vetores e da doença. O monitoramento da ocorrência das cigarrinhas no pomar foi feito através de amostragens mensais, utilizando-se armadilhas adesivas amarelas de 3" x 5", distribuídas uniformemente em 50 pontos na área, dispostas em laranjeiras à altura de 1,5 m do solo e substituídas mensalmente. Acrogonia sp. foi a espécie prevalente nas amostragens. Os resultados possibilitaram ajustar modelos aos semivariogramas da distribuição espacial das três espécies no pomar estudado. Durante os três anos consecutivos de amostragem, as populações de Acrogonia sp., D. costalimai e O. facialis apresentaram modelos de distribuição agregada somente nos meses de verão, inverno e primavera, respectivamente, mostrando a necessidade de monitoramento constante desses vetores para reduzir a sua população em épocas favoráveis ao seu desenvolvimento. Através de parâmetros geoestatísticos foi possível calcular a área de agregação das cigarrinhas no pomar. A espécie Acrogonia sp. apresentou área média de agregação PALAVRAS-CHAVE: Clorose Variegada dos Citros, Citrus sinensis, semivariograma, krigagemABSTRACT -The spatial distribution of the three principal species of sharpshooter (Dilobopterus costalimai Young, Acrogonia sp. e Oncometopia facialis Signoret), vectors of Xylella fastidiosa causal agent of Citrus Variegated Chlorosis, was studied by using geostatistics. The evaluations were carried out in a commercial 'Pera' sweet orange (Citrus sinensis [L.] Osb.) grove budded on Rangpur lime (Citrus limonia Osb.) located at Bebedouro, São Paulo state, aiming to establish better means for vector and disease control. The sharpshooters were monitored using with 50 uniformly distributed 3" x 5" yellow sticky traps hanging down in branches at 1.5 m up to the ground, which were replaced monthly. Acrogonia sp. was the prevalent species sampled. The results were used to adjust population models to semivariograms of the spatial distribution of the three sharpshooters species in the grove. During the three consecutive years of sampling, the population of Acrogonia sp., D. costalimai and O. facialis showed an aggregated distribution only during summer, winter and spring, respectively, showing that intensive monitoring of these vectors is necessary to control their population in periods favorable to their development. The aggregation area of the sharpshooters within the orange grove was determined using geostatistic parameters. Acrogonia sp. showed a mean aggregation area of 15,760 m 2 , whereas for O. facialis and D. costalimai, the...

The spatial dynamics of Citrus Variegated Chlorosis (CVC) was studied in a five-year old commercial orchard of 'Valencia' sweet orange (Citrus sp.) trees, located in the northern region of the state of São Paulo, Brazil. One thousand trees were assessed in 25 rows of 40 trees, planted at 8 x 5 m spacing. Disease incidence data were taken beginning in March 1994 and ending in January 1996, at intervals of four to five months. Disease aggregation was observed through the dispersion index analysis (Ib), which was calculated by dividing the area into quadrants. CVC spatial dynamics was examined using semivariogram analysis, which revealed that the disease was aggregated in the field forming foci of 10 to 14 m. For each well-fitted model, a kriging map was created to better visualize the distribution of the disease. The spherical model was the best fit for the data in this study. Kriging maps also revealed that the incidence of CVC increased in periods during which the trees underwent vegetative growth, coinciding with greater expected occurrence of insect vectors of the bacterium in the field.

Neotropical Entomology 30(4): 721-722 (2001) Diabrotica speciosa (Ger.) (Coleoptera: Chrysomelidae): Nova Praga em Uvas de Mesa RESUMO -Relata-se pela primeira vez a ocorrência de Diabrotica speciosa (Germar.) danificando cachos em florescimento em pomares de videira no Noroeste do estado do Paraná. Em meados de setembro de 2000, os insetos foram verificados alimentado-se dos estiletes, estigmas e eventualmente de porções do ovário. Foram observados até 15 adultos por cacho. A alimentação nos estigmas determinou abortamento de flores. Em áreas com altas populações, os cachos formados apresentaram baixo número de bagas, não se prestando à comercialização. PALAVRAS-CHAVE: Insecta, dano, surto, videira, Vitis vinifera L.ABSTRACT -We report for the first time the occurrence of Diabrotica speciosa (Ger.) damaging blooming clusters in grapevine orchards in Northwest Paraná State. On middle September, 2000, insects were found feeding on style, stigma and eventually on ovary. Up to 15 adults per cluster were observed. Insects feeding on stigma caused flowers aborting. In high population areas, clusters showed low number of fruits and were out of market standards.

A produção de mudas de lichieira (Litchi chinensis Soon.) por meio da estaquia, é uma alternativa promissora visando à redução do período de juvenilidade e à manutenção das características desejáveis da planta matriz. O objetivo deste trabalho foi avaliar o enraizamento de estacas semilenhosas de lichieira cv. Bengal, tratadas com ácido indolbutírico (AIB) em diferentes substratos. O delineamento experimental foi o inteiramente casualizado, em arranjo fatorial 3 x 2, correspondendo aos substratos: casca de arroz carbonizada, vermiculita e fibra de coco e duas concentrações de AIB, a 0 e 1.000 mg L-1 , com cinco repetições de 10 estacas por parcela. Não se constatou influência dos substratos e da concentração de AIB sobre a sobrevivência das estacas. As estacas enraizadas em fibra de coco apresentaram maior retenção foliar. A aplicação de AIB nas estacas na casca de arroz carbonizado e vermiculita resultou nas maiores médias de enraizamento. Obtiveram-se, para a massa seca de raízes, melhores resultados com a vermiculita e o AIB. A utilização de casca de arroz carbonizada e vermiculita-e a aplicação de 1.000 mg L-1 de AIB são as mais indicadas para o enraizamento de estacas de lichieira 'Bengal'.