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Please use this identifier to cite or link to this item: http://hdl.handle.net/10400.5/2053

Title: As cochonilhas-algodão da vinha (Hemiptera: Pseudococcidae) na região do Oeste
Authors: Martins, António Jorge Antunes
Advisor: Silva, José Carlos Franco Santos
Keywords: Planococcus ficus
Pseudococcus viburni
mealybugs
vineyard
cochonilha-algodão
vinha
Região do Oeste
Portugal
Issue Date: 2009
Abstract: Mealybugs are major pests in many grapevine-growing regions in the world, including Mediterranean countries, South Africa and California. The damage caused by mealybugs is linked to sap uptake, honeydew secretion and associated sooty mold development, toxin injection and virus transmission, such as Grapevine Leaf Roll associated Virus-3. In this study we aimed at evaluating the pest-status of mealybugs on vineyards in the Oeste region of Portugal, identifying mealybug species and estimating their infestation level. Therefore, a survey was carried out in 71 grapevine plots, mainly at the counties of Alenquer, Arruda dos Vinhos and Torres Vedras. In the infested plots, samples of adult mealybug females were collected and preserved in 4 parts of 95% alcohol + 1 part of acetic acid for slide mounting and species identification. Information on pest history of mealybugs, possible factors involved on mealybug pest status, as well as on the adopted management strategies was obtained based a questionnaire answered by the farmers or technical managers. All sampled plots were qualitatively evaluated regarding the infestation level of mealybugs, using the following notation: 0 - No detected mealybugs; 1 – Low infestation level; 2 – Moderate infestation level; or 3 – High infestation level. A quantitative estimation of the infestation level was performed in eight selected grapevine plots. Mealybugs were detected on 76% of the sampled plots. Two mealybug species were identified: Planococcus ficus (Signoret) and Pseudococcus viburni (Signoret), in 36 and 22 plots, respectively. Both species were associated only in five plots. Planococcus ficus was the most frequent mealybug species in Alenquer and Arruda counties. On the other hand, Pseudococcus viburni was most frequent in Torres Vedras. About 38% of the farmers carried out at least one insecticide treatment to control mealybugs. Chlorpyriphos was the most used active ingredient. No apparent relationship was observed between grapevine varieties and crop susceptibility to mealybugs. Although, mealybug outbreaks have been more commonly associated with older vineyards, we observed several cases of very young grapevine plots with high levels of mealybug infestation. Possible causes are discussed. Low, moderate and high levels of mealybug infestation were recorded in 51%, 17% e 7% of the plots, respectively. The infestation level in the eight plots studied ranged between 2,2% and 39,9%. The infested plants, within each vine plot, showed a clumped pattern of spatial distribution.----------------------------Este estudo teve como objectivo avaliar a importância relativa das cochonilhas-algodão (CA) da vinha em 3 concelhos da região do Oeste, esclarecer a identidade das espécies existentes e estimar a respectiva intensidade de ataque. Para o efeito, foi realizada uma prospecção, em 71 parcelas, sobretudo, nos concelhos de Alenquer, Arruda dos Vinhos e Torres Vedras. Para além da recolha de amostras, para posterior identificação específica, foi efectuado um inquérito aos proprietários ou aos técnicos das explorações agrícolas, para conhecer o historial dos ataques e respectiva importância, eventuais factores de nocividade, bem como as estratégias de protecção adoptadas. A intensidade de ataque foi estimada qualitativamente em todas as parcelas, tendo-se procedido à estimativa quantitativa em oito parcelas. As CA foram detectadas em 76% das parcelas, tendo-se identificado as espécies Planococcus ficus (Signoret) e Pseudococcus viburni (Signoret), em 36 e 22 parcelas, respectivamente. Cerca de 38% dos inquiridos efectuaram, pelos, menos um tratamento insecticida contra CA, tendo o clorpirifos sido a substância activa mais utilizada. Registaramse ataques fracos, moderados e fortes de CA, em 51%, 17% e 7% das parcelas, respectivamente. A intensidade de ataque nas oito parcelas variou entre 2,2% e 39,9%. As cepas infestadas, dentro de cada parcela, apresentaram padrão de distribuição agregado.
Description: Mestrado em Engenharia Agronómica - Protecção de Plantas - Instituto Superior de Agronomia
URI: http://hdl.handle.net/10400.5/2053
Appears in Collections:BISA - Dissertações de Mestrado / Master Thesis

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