Evaluation of parasitism and predation of Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) by Diglyphus isaea (Walker, 1838) (Hymenoptera: Eulophidae)

To evaluate an eventual parasitism and/or predation behaviour of the eulophid parasitoid Diglyphus isaea (Walker, 1838) on Tuta absoluta (Meyrick, 1917) larvae two assays were performed releasing adult parasitoids. The first assay was conducted in Petri dishes using tomato leaflets havig mines with T. absoluta larvae inside. The second, was performed on previously infested potted tomato plants. In both assays no parasitism but only predation was found. Predation was observed, mainly on L2 and L3 larvae which had moulted. Proportion of clearly preyed larvae reached 17% in Petri dishes and 38% in potted plants. Predation was attested by the presence of punctures done by the oviscapt of the female parasitoid. A significant higher proportion of dead larvae where it was not possible to see punctures occurred in the presence of the parasitoid females. Some of them probably were also preyed on by D. isaea femalesinfo:eu-repo/semantics/publishedVersio

Potential of plant products as protectants of stored maize against Sitophilus zeamais Motschulsky (Coleoptera:Curculionidae)

Laboratory studies were carried out to evaluate the effects of some formulations from Mentha pulegium, Lonchocarpus sericeus, Daphne gnidium, Laurus nobilis, Momordica charantia, Nerium oleander and Ptaeroxylon obliquum as protectants against adult insects of Sitophilus zeamais on stored maize. The dusts from leaves of L. nobilis at 30% w/w caused 86% mortality and reduced F1 progeny emergence up to 57%. At the same concentration, dusts of pink flowers from N. oleander and leaves from L. sericeus reduced the F1 progeny up to 68% and 70%, reduced the developmental index and prolonged the developmental period by 4 and 6 d, respectively. The suspensions (2% v/v) from M. charantia, N. oleander and P. obliquum reduced the F1 progeny emergence up to 58, 91 and 94% and the number of holes in grains by 75, 91 and 97%, respectively. The methanol extracts were more effective than n-hexane extracts and affected the F1 progeny emergence and the developmental index. Keywords: Sitophilus zeamais, Botanical insecticides, Repellence, Insect control agents

The use of essential oils to protect rice from storage fungi

Rice (Oryza sativa) is the main food of half of the population of our planet. The growth of fungi closely associated to the eventual occurrence of mycotoxins can be responsible for serious economic losses and public health risks. Knowledge about the origin of the growth of toxigenic fungi is a prerequisite to the establishment of mycotoxin control programs. Socio-economical and environmental factors led to an extreme reduction of rice availability, while the estimated rice production losses increased in all continents what increases the importance to develop new harmless strategies for the control of fungi affecting stored rice. Natural products from plant origin were screened for the control of main pernicious fungi.In this work we have collected rice samples from different origins (national and imported) and these samples were analysed for fungal infection. Several fungi taxa were isolated: Absidia, Alternaria, Aspergillus, Bipolaris, Botrytis, Chaetomium, Curvularia, Cunninghamela, Epicoccum, Fusarium, Geotrichum, Helicoma, Nigrospora, Penicillium, Pyricularia, Rhizopus, Scytalidium, Stemphylium, Sordaria, Trichoconiella, Trichoderma, Trichothecium and Ulocladium. Some of the fungi isolated are potentially mycotoxigenic. We also studied a way to control the growth of some of these fungi using plant extracts and essential oils from Syzyginum aromaticum and Laurus nobilis. Promising results were obtained.Keywords: Rice, Cereals, Fungi, Bio-pesticides, Plant extracts

A Statistical Approach for Multilingual Document Clustering and Topic Extraction from Clusters

2000 Mathematics Subject Classification: 62H30This paper describes a statistics-based methodology for document unsupervised clustering and cluster topics extraction. For this purpose, multiword lexical units (MWUs) of any length are automatically extracted from corpora using the LiPXtractor extractor - a language independent statistics-based tool. The MWUs are taken as base-features to describe documents. These features are transformed and a document similarity matrix is constructed. From this matrix, a reduced set of features is selected using an approach based on Principal Component Analysis. Then, using the Model Based Clustering Analysis software, it is possible to obtain the best number of clusters. Precision and Recall for document-cluster assignment range above 90%. Most important MWUs are extracted from each cluster and taken as document cluster topics. Results on new document classification will just be mentioned

Influência da fertilização azotada na susceptibilidade de pessegueiro a Phomopsis amygdali - ensaio em vasos

A utilização de doses elevadas de fertilização azotada é frequente em agricultura, devido ao grande efeito que exerce sobre a vegetação das culturas, não sendo, no entanto, tão conhecido o seu efeito na susceptibilidade a parasitas. Para avaliação do efeito da fertilização azotada em pessegueiro na susceptibilidade que esta cultura apresenta a Phomopsis amygdali foi estabelecido um ensaio, que decorreu de Abril de 2003 a Abril de 2007, com pessegueiros da cultivar Springcrest, instalados em vasos e sujeitos a quatro níveis de fertilização azotada – N0 (sem fertilização azotada), N1 (fertilização deficiente), N2 (fertilização considerada adequada ou suficiente) e N3 (fertilização excessiva). No final de cada ciclo vegetativo, procedeu-se à inoculação das plantas com uma cultura de P. amygdali, sendo a avaliação da susceptibilidade quantificada através da medição do comprimento de cada cancro desenvolvido nos locais da infecção. A susceptibilidade a P. amygdali de pessegueiros da cv. Springcrest foi condicionada não só pela fertilização como pelas condições climáticas, nomeadamente a precipitação. A Análise de Correspondências Múltiplas permitiu associar os cancros de grandes dimensões a condições de precipitação mais elevada e doses excessivas de azoto, enquanto os cancros de menores dimensões estiveram associados a condições de precipitação mais baixa não sendo tão marcado o efeito da fertilização azotada

Floral visitors, their frequency, activity rate and Index of Visitation Rate in the strawberry fields of Ribatejo, Portugal : selection of potential pollinators : Part 1

Copyright © 2009 Universita degli Studi di Firenze.This study was carried out in one of the most important strawberry (Fragaria × ananassa Duch.) producing regions of Portugal, the Ribatejo, and aims to describe the quantitative component of visits by strawberry floral visitors under open field conditions. The main objectives were: (1) to assess the flower-visiting insects of the strawberry crop; (2) to evaluate the percentage of frequency (F) and activity rate (AR) in order to determine an Index of Visitation Rate (IVR) for the different categories of visitors. This study allowed us to access the vast spectrum of flower-visiting insects of the strawberry crop and to characterize their visits regarding parameters such as F and AR, used to calculate IVR. Based on the referred index it was possible to highlight three categories of insect visitors: Syrphidae (Diptera), Apis mellifera L. (Hymenoptera) and native bees (Hymenoptera). Other aspects were evaluated such as no. ind/flower throughout three different phases of the blooming period and field conditions. All the parameters allowed us to gather a set of information inherent to each of these categories, which will be useful for conservation and management procedures aiming at adequate pollination of the strawberry crop

Integrated pest management in Portugal: from policies to practices

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.info:eu-repo/semantics/publishedVersio

HISTOLOGICAL STUDIES ON THE STYLET PATHWAY, FEEDING SITES AND NATURE OF FEEDING DAMAGE BY PLANOCOCCUS CITRI (RISSO) (HOMOPTERA: PSEUDOCOCCIDAE) IN SWEET ORANGE

HISTOLOGICAL STUDIES ON THE STYLET PATHWAY, FEEDING SITES AND NATURE OF FEEDING DAMAGE BY PLANOCOCCUS CITRI (RISSO) (HOMOPTERA: PSEUDOCOCCIDAE) IN SWEET ORANGE. Histological studies on the stylet pathway, feeding sites and cell damage caused by the citrus mealybug, Planococcus citri (Risso), on sweet orange (Citrus sinensis (L.) Osbeck) fruit and leaves are described. The frequency of stylet pathways that were exclusively intercellular did not differ significantly from those that were both inter- and intracellular. Stylet track terminations were significantly more frequent in the phloem and its proximity than elsewhere, indicating that the phloem was the preferred feeding site in both fruits and leaves. None of the observed stylet tracks had multiple branches. The majority of plant cells surrounding the stylet tracks showed no detectable damage; only in the fruit did some cells appear slightly enlarged and had a different pigmentation, suggesting that the damage was caused by diffusion of saliva from the stylet. The pierced cells appeared otherwise healthy. Key words: feeding behaviou

Estudo da influência do diâmetero dos orifícios de armadilhas Olipe na luta contra a mosca-da-azeitona, Bactrocera oleae (Rossi).

A mosca-da-azeitona, Bactrocera oleae (Rossi) é praga chave da oliveira na maioria dos países mediterrânicos, sendo também um dos inimigos mais importantes da cultura em Trás-os-Montes. Esta praga pode provocar prejuízos elevados chegando, em alguns anos, a atingir mais de 80% das azeitonas. Em modo de produção biológico, a utilização de armadilhas do tipo Olipe, para captura em massa de adultos de B. oleae, tem sido um método frequentemente utilizado em diferentes regiões da Península Ibérica. Esta armadilha consiste numa garrafa de plástico com capacidade de 1,5 litros, onde são feitos 6 orifícios, a cerca de 1 O cm do topo, e em cujo interior é colocado um atractivo alimentar, em geral uma solução de fosfato biamónico a 3%. Apesar da facilidade de obtenção e do custo reduzido, a sua eficácia necessita de ser melhorada, considerando-se que o diâmetro dos orifícios, um dos aspectos a estudar. Assim, o objectivo do presente trabalho foi avaliar o efeito de diferentes diâmetros dos orifícios (4, 6, 8 e 1 O mm) das armadilhas Olipe na captura de mosca-da-azeitona e nos níveis de ataque nos frutos. O trabalho de campo decorreu em 2009 e 201 O, num olival em modo de produção biológico localizado próximo de Mirandela. O olival foi dividido em cinco blocos com cerca de um hectare. Em quatro dos cinco blocos foram colocadas as armadilhas, a razão de uma armadilha por árvore e por diâmetro de orifício, enquanto no quinto, funcionou como testemunha. O acompanhamento dos níveis populacionais da mosca-da-azeitona foi feito semanalmente através da contagem dos adultos em armadilhas cromotrópicas amarelas com feromona, enquanto para a avaliação dos níveis de ataque, quinzenalmente foram observados 25 frutos por árvore num total de 20 árvores, tendo-se registado o número de frutos e o estado de desenvolvimento do insecto quando este se encontrava presente. Os resultados obtidos mostram que de maneira geral as armadilhas Olipe diminuem os níveis populacionais de B. oleae e consequentemente o nível de ataque nos frutos. Verificou-se também que as armadilhas com diâmetros superiores (8 e 1 O mm) registaram maior número de capturas. Convém contudo registar que diâmetros superiores apresentam um maior impacto na fauna auxiliar dos olivais

SPI-based drought category prediction using loglinear models

Loglinear modeling for three-dimensional contingency tables was used with data from 14 rainfall stations located in Alentejo and Algarve region, southern of Portugal, for short term prediction of drought severity classes. Loglinear models were fitted to drought class transitions derived from Standardized Precipitation Index (SPI) time series computed in a 12-month time scale. Quasi-association loglinear models proved to be the most adequate in fitting all the 14 data series. Odds and respective confidence intervals were calculated in order to understand the drought evolution and to estimate the drought class transition probabilities. The validation of the predictions was performed for the 2004–2006 drought, particularly for periods when the drought was initiating and establishing, and when it was dissipating. Despite the contingency tables of drought class transitions present a strong diagonal tendency, results of three-dimensional loglinear modeling present good results when comparing predicted and observed drought classes with 1 and 2 months lead for those 14 sites. Only for a few cases predictions did not fully match the observed drought severity, mainly for 2-month lead and when the SPI values are near the limit of the severity class. It could be concluded that loglinear prediction of drought class transitions is a useful tool for short term drought warnin