Utilização da Nanotecnologia para o desenvolvimento sustentável na indústria agro-alimentar

O crescimento populacional esperado para os próximos anos conduzirá à necessidade de aumentar a produção agrícola de modo a satisfazer o aumento da procura. Nos últimos anos tem-se assistido a uma evolução tecnológica nos sistemas de produção que tem permitido aumentar a produtividade agrícola, por vezes à custa de elevados consumos de energia e com práticas nem sempre ambientalmente corretas. Os desafios que se colocam atualmente são no sentido de melhorar a conservação de recursos escassos, como o solo e a água, de aumentar a eficiência de uso de fatores de produção, de encontrar novas culturas, do desenvolvimento da biotecnologia, da diminuição dos consumos energéticos e de melhorar ainda mais as tecnologias associadas à produção. De maneira a responder aos desafios emergentes da procura por alimentos, da escassez de terrenos agrícolas aráveis bem como da existência de pragas de insetos e de ervas daninhas, os pesticidas tem vindo a ser usados com maior frequência, tendo-se assistido a uma contaminação dos solos e águas subterrâneas, causando deste modo um risco para a saúde dos seres vivos. Neste sentido, vários fabricantes de pesticidas estão a desenvolver novas formulações contendo pesticidas encapsulados em nanopartículas como modo de aumentar a sua solubilidade em água, biodisponibilidade, volatilidade, estabilidade e eficácia. tendo por objetivo um desenvolvimento sustentável. Neste trabalho, procedeu-se ao estudo do encapsulamento do herbicida Oxadiargil (5-terc-butil-3-[2,4-dicloro-5-(2-propiniloxi)fenil]-1,3,4-oxadiazol-2(3H)-ona) com a 2-hidroxipropil-β-ciclodextrina (HP-β-CD). O estudo da formação do complexo de inclusão Oxadiargil - HP-β-CD foi realizado em diferentes meios, água desionizada, tampão acetato pH = 3,46 e pH = 5,34 e tampão fosfato pH = 7,45, com o objetivo de determinar e comparar a sua constante de estabilidade. Verificou-se, em qualquer dos casos, a ocorrência de uma relação linear entre o aumento da solubilidade do Oxadiargil e o aumento da concentração de HP-β-CD, com um declive inferior a um, o que indicia a formação de um complexo na proporção estequiométrica de 1:1. Os resultados obtidos permitiram concluir que o processo de complexação Oxadiargil - HP-β-CD não é muito influenciado pela constituição e pelo pH do meio. De facto, as constantes de estabilidade obtidas para a água desionizada e soluções-tampão pH = 3,46, pH = 5,34 e pH = 7,45 foram de 919 ± 25, 685 ± 13, 623 ± 17 e 753 ± 9, respetivamente. A solubilidade do complexo obtido nos estudos realizados, em diferentes meios, é cerca de 23 a 32 vezes superior à observada para o Oxadiargil livre. De forma a caracterizar o complexo Oxadiargil - HP-β-CD procedeu-se à sua síntese utilizando o método de “kneading”. O composto obtido foi caracterizado por Ressonância Magnética Nuclear (RMN) tendo-se confirmado a formação de um complexo de inclusão na proporção estequiométrica de 1:1. O complexo obtido é mais solúvel e porventura mais estável quimicamente. O encapsulamento permite uma redução da aplicação dos pesticidas diminuindo assim os custos e o impacto negativo no ambiente. Com a nanotecnologia é possível a libertação controlada dos pesticidas, aumentando a sua eficácia e fornecendo os meios necessários para um desenvolvimento sustentável.

Life cycle of Misumenops pallida (Araneae, Thomisidae)

Postembryonic development of Misumenops pallida (Keyserling) (Araneae, Thomisidae), one of the most abundant predator species in soybean fields in Buenos Aires Province (Argentina) was studied. The life cycle was observed in the laboratory from egg sacs collected in the field, and from egg sacs spined in the laboratory by gravid females collected in the field. Results indicated that instar length and feeding rate increased throughout the life cycle being higher in females than in males. Greater mortality was observed to third and fourth instars decreasing thereafter. These results may contribute to deternmine the efficiency of this species as a natural enemy of insect pests of soybean.

Dinàmica d'esporulació del fong Stemphylium vesicarium en perera i determinació de la viabilitat dels conidis en funció de paràmetres ambientals

L’objectiu del treball és per una banda determinar la dinàmica d’esporulació i emissió de conidis de Stemphylium vesicarium en finques comercials de perera, i per altra banda determinar la viabilitat de la capacitat infectiva i germinativa d’aquests conidis al llarg del temps segons diferents condicions ambientals

Contribució al coneixement del cicle biològic de la carpocapsa (Cydia pomonella (L.)) de pomes i peres a Girona: estimació de l’entrada en diapausa de la població de segona generació

Estudi de la Cydia pomonella (L.), corc de les pomes i de les peres que és una plaga molt important en tot l’àmbit estatal i del control que cal fer-ne per tal d’evitar la pèrdua total o parcial de la collita

Predicted effect of climate change on the invasibility and distribution of the Western corn root-worm

1 Insect pests, biological invasions and climate change are considered to representmajor threats to biodiversity, ecosystem functioning, agriculture and forestry.Deriving hypothesis of contemporary and/or future potential distributions of insectpests and invasive species is becoming an important tool for predicting the spatialstructure of potential threats.2 The western corn rootworm (WCR) Diabrotica virgifera virgifera LeConte is apest of maize in North America that has invaded Europe in recent years, resultingin economic costs in terms of maize yields in both continents. The present studyaimed to estimate the dynamics of potential areas of invasion by the WCR under aclimate change scenario in the Northern Hemisphere. The areas at risk under thisscenario were assessed by comparing, using complementary approaches, the spatialprojections of current and future areas of climatic favourability of the WCR. Spatialhypothesis were generated with respect to the presence records in the native rangeof the WCR and physiological thresholds from previous empirical studies.3 We used a previously developed protocol specifically designed to estimatethe climatic favourability of the WCR. We selected the most biologicallyrelevant climatic predictors and then used multidimensional envelope (MDE) andMahalanobis distances (MD) approaches to derive potential distributions for currentand future climatic conditions.4 The results obtained showed a northward advancement of the upper physiologicallimit as a result of climate change, which might increase the strength of outbreaksat higher latitudes. In addition, both MDE and MD outputs predict the stability ofclimatic favourability for the WCR in the core of the already invaded area in Europe,which suggests that this zone would continue to experience damage from this pestin Europe.

Avaliação da infestação de insetos-praga associados à batata (Solanum tuberosum L.) sob efeito de nutrientes nitrogenados e potássicos e teores acumulados de aminoácidos livres nas cultivares Achat e Monalisa

Evaluation of insect-pest infestation associated to potato (Solanum tuberosum L.) under effect of nitrogen and potassium fertilizers and the accumulated amount of free aminoacids in Achat and Monalisa cultivars. The objective of this work was to evaluate the occurence of insect-pests on potato plants influenced by dosages of nitrogen and potassium accumulated in plant organs. A total of 169 plants of the Achat and Monalisa cultivars were evaluated to determine the presence-absence of Diabrotica speciosa Germar, 1824 and Agrotis ipsilon Hüfnagel, 1767. The experiment was carried out and executed at the Universidade Federal Fluminense, and the delineation was complete randomized block design, with four replication and nine treatments, using three fertilization level (0; 75 and 150 Kg/ha) with N-urea + KCl. The aminoacid levels were adjusted by the Leucine standard-curve (µg/l), using the Ninhydrin method, at 570 nm. The results showed that the tubercles of Monalisa accumulated high free aminoacid levels with 7,95% in the treatment N1K2 and 7,75% in the N2K1.These treatments, induced the infestation by D. speciosa larvae in 27,03%, when the aminoacid level was 2,01 ± 0,58% (X ± EP), with probability of 0,0196

Survey of ear flies (Diptera, Ulidiidae) in maize (Zea mays L.) and a new record of Euxesta mazorca Steyskal in Brazil

Survey of ear flies (Diptera, Ulidiidae) in maize (Zea mays L.) and a new record of Euxesta mazorca Steyskalin Brazil. Species of Euxesta (Diptera, Ulidiidae), known as silk flies or ear flies, are becoming increasingly important as maize insect pests in South America, although very little is known about them in Brazil. The larvae of some species of this genus initially damage female reproductive tissues, and then the developing kernels on the ear. As a result of feeding, fermentation and associated odors cause complete loss of the grain because it is no longer fit for human or livestock consumption. The main objective of this work was to evaluate the incidence of Euxesta spp. in Brazilian maize fields and to determine the most prevalent species using two different hydrolyzed protein foods attractants, BioAnastrepha® (hydrolyzed maize protein) and Torula, placed inside McPhail traps. The two species identified were E. eluta Loew and E. mazorca Steyskal, the latter being a new record from Brazil. Between the two species, E. eluta was the more abundant in maize fields. Both attractants were efficient in capturing the two species. However, BioAnastrepha® captured significantly more insects than Torula.

Effect of gossypol on survival and reproduction of the zoophytophagous stinkbug Podisus nigrispinus (Dallas)

Effect of gossypol on survival and reproduction of the zoophytophagous stinkbug Podisus nigrispinus (Dallas). Gossypol is a sesquiterpene aldehyde found in cotton plants conferring resistance against herbivory. Although the effect of this sesquiterpenoid on insect pests of cotton is known, the interaction of this compound with zoophytophagous predators such as Podisus nigrispinus (Dallas) (Hemiptera, Pentatomidae) has not been studied so far. Thus, the objective of this study was to evaluate the effect of the purified gossypol on nymphs and adults of P. nigrispinus. Nymphs and adults of this predator were fed on Tenebrio molitor pupae and supplemented with solutions of gossypol at concentrations of 0.00, 0.05, 0.10, and 0.20% (w/v) during the nymphal and adult stages or, only during the adult stage of P. nigrispinus. The nymphal stage of the predator was, on average, two days longer when suplemmented with gossypol. Emerged adults had lower fecundity and egg hatching, especially at the highest gossypol concentration (0.20%) ingested during the nymphal and adult stages. However, this predator was not affected when it ingested the compound only during the adult stage. P. nigrispinus can have delayed nymphal development and lower reproductive performance when ingesting the gossypol during the nymphal and adult stages, but only at higher concentrations of gossypol than that produced by cotton plants.

Hypatropis inermis (Hemiptera, Pentatomidae): first record on rice crops

This study reports for the first time the occurrence of Hypatropis inermis on upland rice crops (variety Cambará), in Novo Progresso, state of Pará, Brazil (7°07'45.71"S 55°23'21.13"W). The inventory of insect pests was conducted between November 2010 and March 2011 with entomological sweep nets and visual search on stems of rice plants. This record indicates that rice crops may represent important feeding and mating sites for this species.