Browsing by Author "Mexia, A."
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- Biodiversidade funcional: conservação de artrópodes auxiliares em culturas hortícolas protegidasPublication . Godinho, Maria; Figueiredo, E.; Mateus, C.; Rodrigues, S.; Valério, E.; Mexia, A.A biodiversidade funcional é uma componente importante na protecção das culturas em sistemas mediterrânicos. O conhecimento das espécies presentes e sua dinâmica populacional, assim como dos efeitos secundários dos pesticidas e dos factores que fomentam esta biodiversidade é crucial para o sucesso da protecção biológica assente ma conservação. Os objectivos dos trabalhos desenvolvidos por esta equipa centraram-se na inventariação da fauna auxiliar, definição da sua importância relativa no combate às principais pragas em perspectivar a melhoria da sua actuação baseada em tecnologia de protecção biológica, em particular na biodiversidade funcional.
- O contributo do GO FruitFlyProtect para melhorar a proteção contra a drosófila-de-asa-manchadaPublication . Figueiredo, E.; Godinho, Maria; Simões, M.; Alexandre, P.; Mendonça, T.; Oliveira, M.; Mateus, C.; Valério, Elsa; Mexia, A.Apresentam-se os resultados obtidos no GO FruitFlyProtect relativos às capturas de Drosophila suzukii em armadilhas (dispositivo e isco), para estimativa do risco ou para captura em massa. Utilizaram-se os dispositivos das marcas Econex, Koppert, Biobest, com o isco respetivo, e garrafa PET e dispositivo “Lasa”, construídos artesanalmente e iscados com composto de vinagre da empresa Mendes & Gonçalves Lda. Na armadilha “Lasa” usou-se ainda fermento de padeiro como isco adicional. Mais tarde, incluiu-se o dispositivo da Biobest e respectivo isco. A placa vermelha iscada da Econex nunca capturou D. suzukii. A garrafa PET apresentou capturas mais elevadas e a armadilha Koppert a maior especificidade. Expõem-se problemas detetados na identificação de D. suzukii, nomeadamente a possibilidade de confusão entre as formas de inverno desta espécie e as drosófilas do grupo D. obscura. Avaliou-se, também, a eficácia de três espécies de nemátodes entomopatogénicos no combate a D. suzukii: Steinernema carpocapsae, S. feltiae e Heterorhabditis bacteriophora, tendo S. carpocapsae induzido maior mortalidade que S. feltiae em placa de Petri. Não ocorreu mortalidade em pupas.
- Development of a Tomato spotted wilt virus (TSWV) risk evaluation methodology for a processing tomato regionPublication . Mateus, C.; Pequito, A.; Teixeira, S.; Godinho, Maria; Figueiredo, E.; Amaro, F.; Lacasa, A.; Mexia, A.A risk map for the Tomato spotted wilt virus (TSWV) was elaborated for the main Portuguese processing tomato producing region, the "Ribatejo e Península de Setúbal" region, where periodically this virus causes severe losses. Forty nine tomato fields were monitored. Risk factors for TSWV infection were identified and quantified according to their relative importance in TSWV incidence. The risk factors considered for each field were: (1) presence of TSWV in the crop plants; (2) presence of TSWV in weeds which are hosts of TSWV vectors; (3) presence of TSWV vector thrips; (4) presence of TSWV host crops previously (in the two years before), namely, tomato, potato and sweet pepper; (5) presence of greenhouses, urban areas or TSWV host crops next to the field (up to about 100m from its borders). A risk estimator was calculated for each field. Among the thrips (Thysanoptera) identified, belonging to 11 genera, four vector thrips species were detected: Frankliniella occidentalis (Pergande) and Thrips tabaci Lindman, the two most abundant ones, and F. intonsa (Trybom) and F. schultzei (Trybom). Blue sticky traps placed up to about 75 cm above the crop canopy caught F. occidentalis and T. tabaci more efficiently than the beating technique. The weeds Datura stramonium L., Arctotheca calendula (L.), and Conyza bonariensis (L.) were identified as TSWV winter repositories. This study proposes a methodology to be used by field technicians for the annual evaluation of TSWV risk at a regional level, for an improved planning of processing tomato crop in the following season.
- FruitFlyProtec - Melhorar o combate a moscas da fruta por monitorização e avaliação de eficácia de meios de proteção alternativos para Ceratitis capitata e Drosophila suzukii e avaliação do risco de introdução e distribuição potencial para Bactrocera dorsalisPublication . Alexandre, P.; Mendonça, T.; Godinho, Maria; Valério, Elsa; Figueiredo, E.; Mexia, A.; Soares, C.; Tomé, D.; Neto, E.; Lopes, H.; Pica, M.C.
- Integrated pest management in Portugal: from policies to practicesPublication . Costa1, C. A.; Godinho, Maria; Santos, J.L.; Mexia, A.; Amaro, P.Integrated pest management is an ecosystem approach to crop protection that combines different control methods to reduce pesticide use and to obtain safe food products with lower environmental impact. It has increased in Europe and since 2014, it is mandatory for farmers as a basis for their crop protection strategy. Using the Portuguese context as a case study, the evolution of integrated pest management adoption is analyzed. Country statistics and survey-based data are used to highlight technical differences among farmers, their motivations and attitudes that give rise to environmental benefits and food safety. A survey was applied to vineyards and apple and pear orchards in integrated pest management and in organic and conventional farming. The collected data were related with farmer profile, farm description, farmers’ motivations towards sustainable farming practices, technical itinerary and practices related to pesticide use. A total of 177 questionnaires were applied. Integrated pest management farmers are motivated to adopt biological, biotechnical and cultural solution, even if more expensive, and to give up toxic pesticides, to reduce agricultural impacts, while producing healthier and safer products. Practices that affect crop protection and soil conservation varied between agricultural systems, and can be used as lessons to improve their quality.
- Protecção biológica de conservação e gestão de largadas de auxiliaresPublication . Figueiredo, E.; Martins, J.; Godinho, Maria; Mateus, C.; Valério, E.; Silva, E. B.; Silva, R.; Gago, João; Seabra, S.; Rebelo, M.; Mexia, A.Os complexos de espécies de parasitóides e predadores que limitam as populações das principais pragas de culturas hortícolas protegidas, mosquinhas brancas, larvas mineiras, lagartas, afídeos e tripes, têm vindo a ser estudados na região Oeste desde há mais de 25 anos. A riqueza específica encontrada nestes complexos é elevada. Algumas das espécies identificadas são comercializadas para largadas. Estas largadas podem afectar as populações dos agentes de luta biológica presentes nas culturas, ao nível da composição específica dos complexos, da abundância populacional de cada espécie e na proporção relativa dos vários genótipos presentes nas populações. Está a decorrer uma operação/projecto ProDeR, medida 4.1, promovida por duas empresas agrícolas e três instituições de ensino superior público, que pretende definir regras de actuação no combate às pragas destas culturas face à intensidade de ataque observada e aos auxiliares autóctones presentes e sua abundância, com o objectivo de definir regras para eventuais tratamentos biológicos e analisar as consequências destes, de forma a melhor adequar as estratégias de protecção a adoptar.-------The species complexes of parasitoids and predators which control populations of the main pests of vegetable protected crops have been studied for the last 25 years in the Oeste region. Species richness found in the complexes which prey or parasitize the main pests found in these crops, such as whiteflies, leafminers, caterpillars, aphids and thrips is high. Some of the identified species are commercialized for biological control releases. These releases can affect populations of the naturally occurring biological control agents, regarding species composition of the complexes, species abundance and representativeness of the genotypes present in the populations. A ProDeR - measure 4.1 operation/project promoted by two enterprises and three higher education institutions is ongoing. The aim of this project is to define decision rules to control pests of protected crops taking into account pest attack severity, beneficial arthropod species present and their abundance, and through this to define rules for eventual commercial releases of beneficial arthropods and to analyse their consequences. This will lead to the adoption of more adequate plant protection control measures.
- Protecção integrada em tomate de indústriaPublication . Figueiredo, E.; Godinho, Maria; Mateus, C.; Stilweell, S.; Mexia, A.; Amaro, F.O Projecto Agro 189 –“ Protecção Integrada em Tomate de Indústria” visou o desenvolvimento de uma tecnologia de protecção integrada para o combate aos principais inimigos desta cultura. Um dos objectivos foi a definição de técnicas estimativas do risco que permite fundamentar a tomada de decisão. Os trabalhos foram desenvolvidos durante três anos, em campos de agricultores, tendo- se avaliado a robustez dos métodos de amostragem definidos e a eficácia dos meios de protecção utilizados. Apresentam-se sumariamente, os resultados finais do projecto relativos à estimativa do risco, para o Ribatejo e Península de Setúbal, para três inimigos chave: lagarta do tomate, míldio e TSWV, com base em contagem de ovos, modelo de previsão e mapeamento de zonas de risco, respectivamente.
- Risk assessment for tomato fruitworm in processing tomato crop-egg location and sequential samplingPublication . Figueiredo, E.; Gonçalves, C.; Duarte, S.; Godinho, Maria; Mexia, A.; Torres, L.The tomato fruitworm, Helicoverpa armigera, is a key pest of several crops. It can cause particularly extensive damage in crops of processing tomatoes. Risk assessment can be a tedious and costly task if sampling protocols require a large number of plants. Sequential sampling allows sampling of a reduced number of plants when population densities are much lower or much higher than the economic or control threshold. Additionally, for crop protection purposes, sampling for classification (to assess if population density is lower or higher than the economic threshold) is adequate and requires much less effort. We studied the preferred location of eggs found on plants and then described the spatial pattern of oviposition in processing tomatoes using Taylor's power law. Eggs were found more frequently in the exposed canopy in the upper and middle-upper strata, directly below open flower clusters, with an aggregated spatial pattern. A sequential plan was developed for 20 and 80 plants, as minimum and maximum sample sizes, respectively. This reduces sampling efforts and costs when compared to the fixed number sampling plan, and provides acceptable precision in decision-making for this pest in a processing tomato crop.Helicoverpa armigera is one of the key pests affecting processing tomatoes and many other crops. A three-year study was conducted to describe the oviposition preferences of this species on determinate tomato plants (mainly the stratum, leaf, leaflet, and leaf side) and the spatial pattern of the eggs in the field, to form a sequential sampling plan. Eggs were found mainly in the exposed canopy, on leaves a (upper stratum) and b (upper-middle stratum) and significantly fewer eggs on leaf c (middle-lower stratum) below flower clusters. This vertical pattern in the plant was found in all phenological growth stages. The spatial pattern was found to be aggregated, with a trend towards a random pattern at lower densities. A sequential sampling plan was developed, based on Iwao's method with the parameters of Taylor's power law, with minimum and maximum sample size of 20 and 80 sample units (plants), respectively (two leaves/plant). For its validation, operating characteristic (OC) and average sample number (ASN) curves were calculated by means of simulation with independent data sets. The beta-error was higher than desirable in the vicinity of the economic threshold, but this sampling plan is regarded as an improvement both in effort and precision, compared with the fixed sample plan, and further improvements are discussed.