The nanoencapsulation of botanical compounds (such as geraniol) is an important strategy that can be used to increase the stability and efficiency of these substances in integrated pest management. ...In this study, chitosan/gum arabic nanoparticles containing geraniol were prepared and characterized. In addition, evaluation was made of the biological activity of geraniol encapsulated in chitosan/gum arabic nanoparticles toward whitefly (Bemisia tabaci). The optimized formulation showed a high encapsulation efficiency (>90%) and remained stable for about 120 days. The formulation protected the geraniol against degradation by UV radiation, and the in vitro release was according to a diffusion mechanism that was influenced by temperature. An attraction effect was observed for Bemisia tabaci, indicating the potential of this type of system for use in pest management, especially in trap devices.
Spodoptera frugiperda is a pest of economic importance for several crops with resistance reports to Bt crops and pesticides. Eco-friendly Bt biopesticides may be an alternative to chemical ...insecticides due to their selectivity and specificity. However, the efficacy of Bt biopesticides may be influenced by the association with other chemicals, such as adjuvants. This study evaluated the compatibility and toxicity of Bt biopesticides mixed with adjuvants for the control of S. frugiperda. The treatments included the association of Dipel SC and Dipel PM with adjuvants. Compatibility tests were used to evaluate the Bt mixture. Bt suspensions obtained from mixtures of Bt and adjuvants at 10
and 3 × 10
spores/mL
were used to evaluate S. frugiperda mortality and distilled water was used as the control. The addition of the adjuvant LI increased growth and sporulation, indicating compatibility with Bt biopesticides. The other adjuvants were toxic to reducing Bt growth and sporulation. Only the mixture of Bt with LI and Bt alone was effective to S. frugiperda. The addition of adjuvants to Bt biopesticide affect the Bt sporulation, growth and mortality.
Anastrepha grandis (Macquart) is one of the main pests of cucurbits in the countries of Central and South America. Besides direct damage caused to fruits, A. grandis occurrence in producing regions ...can lead to export embargos. Despite its economic importance, little is known of the effects of temperature on its biology. This study investigated the development of A. grandis under different temperatures to estimate thermal requirements and then validated the model developed in the field. Development time was inversely proportional to temperature and greater fecundity and fertility were observed at 25 °C. Greater egg and pupa viabilities as well as a greater number of insects per fruit were also observed at 25 °C. The thermal threshold and the thermal constant for egg and pupal stages were 8.3 °C for both stages and 132.3 degree-days (DD) for the egg stage and 347.0 DD for the pupal stage. For the egg-to-adult period the values were 5.2 °C and 858.7 DD. Data collected in the field showed DD (937.9) and duration (79.7 d) values of the egg-to-adult period similar to those estimated in the laboratory. This information could support management of A. grandis, since the model for temperature requirements can be used to predict pest occurrence in crops and estimate the number of generations per year.
•The relationship between thermal conditions and A. grandis development was observed.•The work provides benefits for pest management in different regions and ecosystems.•The thermal requirements of A. grandis were established.
Currently the area with the inundative release of Cotesia flavipes (Cameron) in the country is approximately 3.5 million hectares per year in regions of tropical and subtropical climate, but there ...are questions about its efficiency since they are not considered the thermal requirements of the strains used. The objective of the study was to evaluate the biology in different thermal conditions of five C. flavipes strains, from different places of origin. Insects from Paraná (Strain PR), Minas Gerais (Strain MG), Alagoas (Strain AL) and two strains from São Paulo state (SPI and SPII strains) were submitted to different constant temperatures (10, 15, 18, 20, 22, 25, 30, and 32°C), relative air humidity of 70 ± 10% and 12-h photophase. The duration the egg-adult of C. flavipes was inversely proportional to the temperature in the thermal range of 18 to 30°C. No development occurred at temperatures of 10, 15, and 32°C. The highest survival of the biological cycle (egg-adult) (above 70%) occurred in the thermal range of 25 to 28°C. Also, temperatures from 28 to 30°C characterize significantly more females than males (sex ratio > 0.70). Based on the development of the biological cycle, the threshold temperature (Tt) was similar among the C. flavipes strains (ranging from 9.6 to 11.1°C), providing the thermal constants of 229.4 to 273.9 degree-days. The biological control of Diatraea saccharalis (Fabricius 1794) (Lepidoptera: Crambidae) may be more efficient to use C. flavipes strains more adapted to the thermal conditions of each region.
Anastrepha grandis (Macquart) (Diptera: Tephritidae) is one of the main pests of cucurbits in Brazil. Losses occur due to the damage caused to the fruits and the embargo on exports, as A. grandis is ...considered a quarantine pest in countries that import Brazilian cucurbits. This study aimed to evaluate the development of A. grandis in hosts of the Cucurbitaceae family. The hosts used were stem squash (Cucurbita pepo L.), squash (Cucurbita moschata Duchesne), chayote Sechium edule (Jacq.) Swartz, mini watermelon Citrullus lanatus (Thunb.) Matsum & Nakai, Spanish melon (Cucumis melo L.), hybrid squash “Tetsukabuto” (C. moschata × Cucurbita maxima Duchesne), and salad cucumber (Cucumis sativus L.). We evaluated the viability and duration of egg-to-pupa period, pupal weight, sex ratio, and average number of pupae per fruit under controlled conditions of temperature, relative humidity, and photophase. The preoviposition and oviposition periods, fecundity, fertility, and longevity of females were determined for adults. Hosts of the genus Cucurbita provided a better development of A. grandis in comparison with other hosts, and presented a greater number of insects on fruit as well as higher infestation rate. Fecundity and longevity were also higher for females that developed in hosts of the genus Cucurbita, although values of these biological parameters varied between stem squash, squash, hybrid squash “Tetsukabuto.”
Orientador: Ricardo Antonio Polanczyk
Resumo: A cana-de-açúcar possui grande destaque no cenário econômico mundial, por ser matéria prima para a produção de açúcar, etanol e uma diversidade de ...produtos secundários. Esta cultura vem se expandindo para novas áreas agricultáveis do Brasil e consequentemente fatores que limitam a produtividade também se fazem presente. Um dos fatores limitantes são os insetos-pragas. Para cana-de-açúcar estima-se que existam aproximadamente 80 espécies de insetos causando danos. Dentre estas espécies, Sphenophorus levis Vaurie, 1978 (Coleoptera: Curculionidae) é a principal praga de solo, causando perdas significativas na produção. O uso de fungos entomopatogênicos tem se mostrado promissor para o controle deste inseto-praga. Dentre estes fungos, Beauveria bassiana (Hypocreales: Cordycipitaceae) se apresenta como um agente promissor para o controle desta praga; porém é suscetível a fatores abióticos, como radiação UV, que reduzem a sua eficiência em campo. Outro fator limitante ao uso deste agente é a falta de conhecimento em relação compatibilidade com inseticidas químicos. Estas informações são úteis para o uso associado destes dois métodos de controle. Tendo em vista estas problemáticas, o presente estudo teve como objetivo realizar testes de compatibilidade com inseticidas químicos e o encapsulamento de um isolado de B. bassiana para diminuir os efeitos da radiação UV. O encapsulamento do fungo foi realizado pelo método de gelificação iônica, com uma suspensão de alginato de sódio conten... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Sugarcane has great prominence in the economic scenario worldwide, for being raw material to produce sugar, ethanol, and diversity of secondary products. This culture has been expanding to new agricultural areas in Brazil and, consequently, factors limiting productivity are present as well. One of the limiting factors is insect-pests. To estimate the amount of sugarcane in existence, approximately 80 insect species cause damage. Among these species, Sphenophorus levis Vaurie, 1978 (Coleoptera: Curculionidae) is one of the main soil pests, which leads to production losses. The use of entomopathogenic fungi is promising for controlling this pest. Among entomopathogenic fungi, Beauveria bassiana (Hypocreales: Cordycipitaceae), present itself as a promising agent for the control of this pest; however, it may be susceptible to abiotic factors such as UV radiation, which affect its efficiency under field conditions. Another limiting factor to the use of this agent is the lack of knowledge regarding the compatibility with chemical insecticides. This information is useful for the use of both control methods. Given these problems, the present study aimed to encapsulate a B. bassiana isolate to reduce the effects of UV radiation and compatibility with chemical insecticides. The encapsulation of the fungus was performed by the ionic gelation method, with a suspension of silicon alginate, or the fungus in a calcium chloride solution. Pathogenicity test was performed with dry and wet part... (Complete abstract click electronic access below)
Doutor
The use of biodiesel in compression ignition (CI) engines has great potential to reduce emissions and the dependence on fossil fuels. However, the complete adoption of biodiesel in CI engines is ...limited by several drawbacks. A promising solution to these problems is the addition of nanoparticles to biodiesel or diesel-biodiesel blends. Hence, this paper studies the impact of adding aluminum oxide (Al2O3) nanoparticles on the performance and emission characteristics of a diesel engine running on biodiesel and a mixture of diesel and biodiesel. Al2O3 nanoparticles were added at concentrations of 50, 100 and 150 ppm to biodiesel (B100) and a mixture of 50 % biodiesel and 50 % commercial diesel (B50). The results indicated an increase in fuel conversion efficiency and a reduction in specific fuel consumption. The highest fuel conversion efficiency was 26.5 % for B50 with 100 ppm of Al2O3, indicating an improvement of around 28.6 % compared to diesel fuel (B0). In general, CO emissions were reduced with the addition of nanoparticles, with a maximum reduction of 42.8 % for B100 with 50 ppm Al2O3 compared to B0. The highest reduction in NOX emissions was 30.3 % for B50 with 100 ppm Al2O3 compared to pure diesel B0.
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